Biomarker expression and survival in patients with non-small cell lung cancer receiving adjuvant chemotherapy in Denmark

Tapashi Dalvi; Mette Nørgaard; Jon P. Fryzek; Naimisha Movva; Lars Pedersen; Hanh Pham Hansen; Jill Walker; Anita Midha; Norah Shire; Anne-Marie Boothman; James Rigas; Anders Mellemgaard; Torben R. Rasmussen; Stephen Hamilton-Dutoit; Deirdre Cronin-Fenton

doi:10.1371/journal.pone.0284037

Abstract

Introduction

Programmed cell death ligand-1 (PD-L1) expression may help identify patients with non-small cell lung cancer (NSCLC) who would benefit from immunotherapy. We assessed PD-L1 expression, and epidermal growth factor receptor (EGFR) and V-Ki-Ras2 Kirsten rat sarcoma (KRAS) mutations in NSCLC patients receiving adjuvant chemotherapy.

Methods

Data for stage IB/II/IIIA NSCLC patients (diagnosed: 2001–2012) were retrieved from Danish population-based registries. Tumor tissue samples were tested for PD-L1 expression using VENTANA PD-L1 (SP263) Assay in tumor cells (TC) at ≥25% cutoff and immune cells (IC) at ≥1% and ≥25% cutoffs. KRAS and EGFR mutations were tested using PCR-based assays. Follow-up began 120 days after diagnosis until death/emigration/January 1, 2015, whichever came first. Using Cox proportional hazard regression, hazard ratios (HRs) were computed for overall survival (OS) for each biomarker, adjusting for age, sex, histology, comorbidities, and tissue specimen age.

Results

Among 391 patients identified, 40.4% had stage IIIA disease, 49.9% stage II, and 8.7% stage IB. PD-L1-TC was observed in 38% of patients, EGFR mutations in 4%, and KRAS mutations in 29%. KRAS mutations were more frequent among patients with PD-L1 TC≥25% versus TC<25% (37% versus 24%). OS was not associated with PD-L1 TC≥25% versus TC<25% (stage II: adjusted HR = 1.15 [95% confidence interval: 0.66–2.01]; stage IIIA: 0.72 [0.44–1.19]). No significant association was observed with OS and PD-L1-IC ≥1% and ≥25%. EGFR and KRAS mutations were not associated with a prognostic impact.

Conclusion

A prognostic impact for NSCLC patients receiving adjuvant chemotherapy was not associated with PD-L1 expression, or with EGFR and KRAS mutations.

Citation: Dalvi T, Nørgaard M, Fryzek JP, Movva N, Pedersen L, Pham Hansen H, et al. (2023) Biomarker expression and survival in patients with non-small cell lung cancer receiving adjuvant chemotherapy in Denmark. PLoS ONE 18(4): e0284037. https://doi.org/10.1371/journal.pone.0284037

Editor: Afsheen Raza, Abu Dhabi University, UNITED ARAB EMIRATES

Received: September 1, 2022; Accepted: March 22, 2023; Published: April 11, 2023

Copyright: © 2023 Dalvi et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Data Availability: Danish law does not allow researchers to share raw data from the registries with third parties. Data can be accessed by researchers through application to the Danish Data Protection Agency (dt@datatilsynet.dk) and the Danish Health Data Authority (kontakt@sundhedsdata.dk). Permission to access, handle, and analyze the data for the present study was obtained from the Danish Data Protection Agency via reporting to Aarhus University (journal number 2016-051-000001, case number 24).

Funding: This work was funded by AstraZeneca research grants to EpidStat Institute (now EpidStrategies) to manage and administer the work. Aarhus University, Denmark, received funds from EpidStat Institute to conduct the work. The funder provided support in the form of salaries for authors Tapashi Dalvi, Jill Walker, Anita Midha, Norah Shire, Anders Mellemgaard, and Anne Marie Boothman. The specific roles of these authors are articulated in the ‘author contributions’ section. The authors had the final responsibility for the decision to submit the manuscript for publication. The funder was involved in the study design and preparation of the manuscript. This does not alter our adherence to PLOS ONE policies on sharing data and materials.

Competing interests: Tapashi Dalvi, Jill Walker, Anita Midha, Norah Shire, Anders Mellemgaard, and Anne Marie Boothman are employees of AstraZeneca. Tapashi Dalvi, Jill Walker, Anita Midha, and Anne Marie Boothman own stock in AstraZeneca. Jon P. Fryzek and Naimisha Movva are employees of EpidStrategies. James Rigas was an employee of AstraZeneca during the study period. This does not alter our adherence to PLOS ONE policies on sharing data and materials. However, Danish law does not allow researchers to share raw data from the registries with third parties. Data can be accessed by researchers through application to the Danish Data Protection Agency and the Danish Health Data Authority. This does not alter our adherence to PLOS ONE policies on sharing data and materials.

Introduction

Lung cancer is the leading cause of cancer-related mortality, with 1.8 million deaths estimated worldwide in 2018, representing 18.4% of total deaths from cancer [1]. The 5-year survival rates for lung cancer for the years 1999–2007 were 13.0% in Europe and 10.3% in Denmark [2]. Survival rates have improved over time, with more recent data (2012–2016) from Denmark indicating age-standardized 5-year relative survival rates for lung cancer of 14% in men and 20% in women [3].

Non-small cell lung cancer (NSCLC) accounts for approximately 85% of all lung cancer cases [4]. The European Society for Medical Oncology recommends surgery for the treatment of patients with early-stage, resectable NSCLC [5]. Patients with stage II/III NSCLC receiving adjuvant chemotherapy have an overall absolute survival improvement of 4%–5% at 5 years compared with those undergoing surgery alone [6]. Despite surgical resection with curative intent, approximately half of the patients with early-stage NSCLC experience disease relapse [6,7], and approximately 30%–55% of patients die from relapse [8]. Multiple immunotherapy agents targeting the programmed cell death-1 (PD-1)/programmed cell death ligand-1 (PD-L1) pathway have demonstrated clinical benefit and are approved for the treatment of patients with locally advanced/metastatic NSCLC [9,10]. For instance, pembrolizumab, a humanized anti-PD-1 antibody, in combination with pemetrexed and platinum chemotherapy demonstrated a survival benefit compared with pemetrexed and platinum chemotherapy plus placebo (median overall survival (OS): not reached versus 11.3 months) at a median follow-up of 10.5 months [11]. Similarly, durvalumab, an anti-PD-L1 antibody, prolonged median OS compared with placebo (not reached versus 28.7 months; median follow-up: 25.2 months) in patients with stage III, unresectable NSCLC and no disease progression after concurrent chemoradiotherapy [12].

PD-L1 expression on tumor cells (TCs) correlates with poor survival in melanoma, and urothelial, pancreatic, hepatocellular, and ovarian carcinomas [13–17]. In addition to being a prognostic marker, PD-L1 may also be useful for predicting patients who might benefit from anti-PD-1/PD-L1 therapies.

NSCLC tumors also harbor mutations in genes such as epidermal growth factor receptor (EGFR) and V-Ki-Ras2 Kirsten rat sarcoma (KRAS) [18,19]. Along with PD-L1 expression, such mutations can help further characterize patient populations. Mutant forms of EGFR upregulate PD-L1 expression in NSCLC, providing a direct link between oncogenic drivers and immune blockade [20]. Clinical data examining the association of PD-L1 expression and EGFR and KRAS biomarkers with survival in NSCLC may help elucidate the interplay between these biomarkers and any potential effect on patient prognosis.

Using a cohort of patients with stage IB/II/IIIA NSCLC receiving adjuvant chemotherapy, identified through population-based and medical registries in Denmark, we characterized PD-L1 expression in conjunction with EGFR and KRAS mutations, and their association with survival. Our primary objective was to assess PD-L1 expression in tumors by stage. Our secondary objectives were to evaluate OS by PD-L1 expression level on TCs, and by KRAS and EGFR mutation status, and by overlap between PD-L1 expression and EGFR and/or KRAS mutations. OS by PD-L1 expression on immune cells (ICs) and by percent of tumor-infiltration with ICs were evaluated as exploratory objectives. Understanding the prevalence and role of PD-L1, EGFR, and KRAS in adjuvant chemotherapy will provide a historical context for researchers, regulators, physicians, and payers as new trials are being designed and new drugs are being approved.

Methods

Study design and patients

We ascertained data on patients, formalin-fixed, paraffin-embedded (FFPE) tumor tissue availability, clinical characteristics, and vital status through the following Danish registries linked on an individual-level via the civil personal registration (CPR) number: the Danish Cancer Registry of mandatory cancer reporting [21,22]; the Danish Lung Cancer Registry of all lung cancers diagnosed in Denmark since 2000 [23]; the Danish National Patient Registry [24,25], which contains inpatient, outpatient, and emergency room visit information; the Danish National Pathology Registry, which contains detailed nationwide records of all pathology specimens analyzed in Denmark [26]; and the Civil Registration System, an administrative register that includes sex and dates of birth and death [27] (S1 Fig). The study was granted ethical approval by the Scientific Ethical Committee of the Central Denmark Region (reference number: 1-10-72-14-15). The use of registry-based data in this study was based on the General Data Protection Regulation Art. 9 (2), j), Art. 6 (1), e); and the Danish Data Protection Law §11. Due to the use of archival tissue and registry-based data, informed consent was not required. We had access to CPR numbers for data linkage purposes. No other personally identifiable information was used.

We included Danish citizens (aged ≥18 years) with NSCLC diagnosed between 2001 and 2012 and FFPE primary tumor tissue available from pathology archives [26] for the analysis of molecular markers. Receipt of adjuvant chemotherapy was defined as surgery within the first 60 days of diagnosis of stage IB/II/IIIA NSCLC and initiation of chemotherapy within 120 days of diagnosis. No other clinical or biological criteria were used for patient selection. We selected eligible patients from 2012 backwards until the target number of patients were enrolled.

Tumor samples and biomarker assessment

Using the Danish National Pathology Registry, we identified FFPE tumor tissue samples from study patients, comprising diagnostic biopsies or surgical resection specimens. Representative tissue blocks were obtained from the pathology archives of hospitals throughout Denmark. FFPE blocks, which are routinely used for immunohistochemistry (IHC) analyses, were sectioned at a thickness of 4–5 μm and mounted on positively charged slides. The study pathologist reviewed a hematoxylin and eosin–stained section to confirm the original NSCLC diagnosis and to ensure that specimens contained ≥100 TCs per section. Labeled slides were shipped at ambient temperature to Hematogenix Laboratory Services (Tinley Park, IL) for the staining and scoring of PD-L1 expression levels using the VENTANA PD-L1 (SP263) Assay (Ventana Medical Systems Pvt. Ltd., Tucson, AZ) according to the manufacturer’s instructions and a predefined scoring algorithm by manufacturer-trained pathologists [28,29]. We evaluated PD-L1 expression levels on the TC membrane and on tumor-associated ICs at cutoffs of 25% and 1% (TC ≥25%, IC ≥25%, and IC ≥1%) based on the clinical trial protocols [30] at that time and the VENTANA PD-L1 assay limitations. Tumor infiltration by immune cells, irrespective of PD-L1 expression, was provided as a percent of total tumor-associated ICs. We detected mutations in the KRAS (exons 2 and 3: codon 12, codon 13, or codon 61 mutations) and EGFR (exons 18–21: G719X, S768I, T790M, L858R, exon 19 deletion, or exon 20 insertion) genes in tumor tissues using the Cobas^® polymerase chain reaction (PCR)-based system (Roche Molecular Systems Inc, Branchburg, NJ, USA; CE-IVD 5852170190, CE-IVD 6471463190). We extracted and purified tumor DNA using the Cobas® DNA Sample Preparation Kit (Roche Molecular Systems Inc., Branchburg, NJ) for FFPE tumor tissue specimens according to the manufacturer’s instructions.

Study variables and covariates

Registry covariates of interest included tissue specimen age, patient age at diagnosis (as a continuous variable), sex, American Joint Committee on Cancer stage at diagnosis (7^th edition), tumor site, histology (adenocarcinoma or other [i.e. squamous, large-cell, adenosquamous, and non-small carcinomas, and carcinoids]), Eastern Cooperative Oncology Group performance status (ECOG PS), comorbidities (recorded up to 10 years before NSCLC diagnosis and registered in the Danish National Patient Registry) using Charlson Comorbidity Index, and smoking status.

Statistical analysis

We provided descriptive statistics for all covariates of interest and constructed Kaplan-Meier curves for each survival outcome stratified by PD-L1 expression level category and EGFR and KRAS mutation status. OS was defined as the time from 120 days after primary diagnosis to death due to any cause. We used Cox proportional hazard regression analysis to compute hazard ratios (HRs) and associated 95% confidence intervals (CIs) adjusting for age, sex, comorbidities, tissue specimen age, and adenocarcinoma histology (versus other). The Breslow and Efron methods for Cox regression were used for handling ties. Follow-up began 120 days after diagnosis and continued until death, emigration, or the end of follow-up (January 1, 2015), whichever came first. Patients without an event during follow-up were censored at the end of the follow-up period. For patients with stage IB NSCLC, the numbers were too small to conduct multivariable analyses and not described further.

Results

Our study cohort included 391 patients with NSCLC who received adjuvant chemotherapy (Fig 1). Overall, 40% of patients were diagnosed with stage IIIA disease, 50% with stage II, and 9% with stage IB.

Download:

Fig 1. Patient disposition.

EGFR, epidermal growth factor receptor; FFPE, formalin-fixed, paraffin-embedded; KRAS, V-Ki-Ras2 Kirsten rat sarcoma; NSCLC, non-small cell lung cancer; PD-L1, programmed cell death ligand-1.

https://doi.org/10.1371/journal.pone.0284037.g001

PD-L1 expression

PD-L1 TC ≥25% and TC <25% was observed in 38% and 62% of patients, respectively (Table 1). Patients with PD-L1 TC ≥25% compared with those with PD-L1 TC <25% were more likely to be <65 years old (62.0% versus 52%), female (55% versus 49%), and smokers (59% versus 47%). ECOG PS was better for patients with PD-L1 TC ≥25% compared with those with TC <25% (41% versus 28% were fully active without restrictions [ECOG PS grade 0]). Adenocarcinoma was the most common histological subtype across all patients, irrespective of their PD-L1 expression levels (approximately 60%).

Download:

Table 1. Baseline demographics, disease characteristics, and medical history of patients with NSCLC receiving adjuvant chemotherapy by PD-L1 expression level, EGFR mutation, and KRAS mutation.

https://doi.org/10.1371/journal.pone.0284037.t001

Overall Survival by PD-L1 expression level

Median OS was not yet reached at the end of follow-up for patients with stage II NSCLC (Fig 2A). Among patients with stage IIIA NSCLC, median OS was 56 months (95% CI: 26.1–not reached) for patients with PD-L1 TC <25% and was not reached for those with PD-L1 TC ≥25%.

Download:

Fig 2.

Kaplan-Meier curves for OS in patients with stage II and stage IIIA NSCLC receiving adjuvant chemotherapy according to PD-L1 expression (A), EGFR mutation status (B) and KRAS mutation status (C). ^aNeither the survival estimate nor the upper confidence limit reached the 50^th percentile. CI, confidence interval; EGFR, epidermal growth factor receptor; KRAS, V-Ki-Ras2 Kirsten rat sarcoma; NR, not reached; NSCLC, non-small cell lung cancer; OS, overall survival; PD-L1, programmed cell death ligand-1; TC, tumor cell.

https://doi.org/10.1371/journal.pone.0284037.g002

Adjusted survival analyses for PD-L1 TC ≥25% compared with PD-L1 TC <25% yielded an HR of 1.15 (95% CI: 0.66–2.01) in stage II and 0.72 (95% CI: 0.44–1.19) in stage IIIA. Analyses of PD-L1 IC expression levels at IC ≥25% yielded adjusted HRs of 0.78 (95% CI: 0.39–1.56) and 0.76 (95% CI: 0.43–1.34) in stages II and IIIA, respectively. PD-L1 expression levels at IC ≥1% yielded similar HRs in stages II and IIIA (0.72 [95% CI: 0.35–1.48] and 0.68 [95% CI: 0.38–1.22], respectively; Table 2). The percent of tumor infiltration by ICs was associated with an adjusted HR of 0.96 (95% CI: 0.92–1.00) in stage II and 0.97 (95% CI: 0.94–1.00) in stage IIIA (Table 2). Median survival was not reached, but the Kaplan-Meier estimate of 25% survival (i.e., the timepoint where 25% of the study population survived) was greater in patients with stage II NSCLC with PD-L1 TC<25% compared with those with PD-L1 TC ≥25%; however, among patients with stage IIIA NSCLC, those with PD-L1 TC ≥25% demonstrated longer survival (S1 Table).

Download:

Table 2. Adjusted HR for OS by biomarker status in patients with stage II or stage IIIA NSCLC receiving adjuvant chemotherapy.

https://doi.org/10.1371/journal.pone.0284037.t002

EGFR mutation status

Few patients (3.6%) had a tumor with an EGFR mutation (Table 1). Patients with EGFR wild-type tumors compared with those with EGFR-mutated tumors were more likely to be ≥65 years old (45% versus 36%) and less likely to be female (51% versus 64%). Tumors with EGFR mutations were more likely to be associated with an adenocarcinoma histology compared with EGFR wild-type tumors (79% versus 61%).

KRAS mutation status

Twenty-nine percent of patients had tumors with ≥1 KRAS mutation (Table 1). Patients with KRAS-mutated tumors were more likely to be female (67% versus 45%) and smokers (55% versus 50%) compared with patients without the mutation. Adenocarcinoma was the most common histology among patients with a KRAS mutation (88%). For KRAS wild-type tumors, adenocarcinoma (50%) and squamous (43%) histology were equally likely.

Overall Survival by EGFR and KRAS mutations

Median OS among stage II patients with EGFR wild-type and mutated tumors and in stage IIIA patients with EGFR mutated tumors was not reached (Fig 2B). Adjusted survival analyses for EGFR-mutated tumors compared with wild-type tumors yielded an HR of 0.91 (95% CI: 0.22–3.79) in stage II and 0.58 (95% CI: 0.08–4.30) in stage IIIA (Table 2). Given the low frequency of patients with EGFR mutations, we were unable to draw conclusions regarding the association of EGFR mutations with survival. Median OS among patients with KRAS-mutated and wild-type tumors was not reached in stage II; however, for stage IIIA, median OS was 44 months (95% CI: 21.9–not reached) and 113.2 months (95% CI: 26.8–not reached), respectively (Fig 2C). Adjusted survival analyses for patients with KRAS-mutated tumors compared with wild-type tumors yielded an HR of 1.54 (95% CI: 0.81–2.93) and 0.88 (95% CI: 0.50–1.53) in stages II and IIIA, respectively (Table 2).

Association of PD-L1 expression levels with EGFR and KRAS mutations

No associations were observed between PD-L1 expression in TCs at 25% cutoff and EGFR mutations (PD-L1 TC ≥25% versus PD-L1 TC <25%, <3% versus 5%, respectively). Patients with PD-L1 TC ≥25% were more likely to have tumors with a KRAS mutation than those with PD-L1 TC <25% (37% versus 24%; Table 3). Similar results were seen when patients were grouped by stage for KRAS-mutated tumors (38% versus 24% for stage II tumors); the numbers were too small to report for EGFR-mutated tumors by stage (S2 Table).

Download:

Table 3. PD-L1 expression level by EGFR and KRAS mutation status in patients with NSCLC receiving adjuvant chemotherapy^a.

https://doi.org/10.1371/journal.pone.0284037.t003

Discussion

In tumors from patients with NSCLC who received adjuvant chemotherapy, a prognostic impact was not observed with PD-L1 expression at TC ≥25%/IC ≥25%/IC ≥1% cutoffs, or with KRAS mutations. However, tumors from patients who had PD-L1 TC ≥25%, were more likely to harbor KRAS mutations compared with those with PD-L1 TC<25%. Additionally, we observed no OS benefit with increasing tumor membrane infiltration with immune cells. Due to the low prevalence of patients with EGFR mutations, we could not evaluate their association with survival.

The NSCLC stage distribution in our study population was similar to that in the LuCaBIS (Lung Cancer Burden of Illness Study) population [31]. Most study patients smoked tobacco, as is observed in the general Danish population [32]. Notably, a history of smoking was more likely to be associated with PD-L1 TC ≥25% expression compared with PD-L1 TC <25%. However, no association between smoking and PD-L1 expression has been reported in patients with surgically resected early-stage or advanced NSCLC [33–35]. Previous reports indicate no consensus regarding a possible association between PD-L1 expression levels and tumor histology. One study showed PD-L1 expression to be associated with adenocarcinomas [36], while a second study reported an association with squamous carcinomas [37]. In contrast, consistent with our findings, two other studies of 204 [38] and 109 [39] patients each, with advanced NSCLC found no association between PD-L1 expression and tumor histology.

While we found PD-L1 expression at TC ≥25% in approximately one-third of study tumors, comparison with findings from other studies was challenging due to varying PD-L1 expression thresholds. In an observational study including 2634 patients with locally advanced/metastatic NSCLC from 18 countries, the percentage of tumors with PD-L1 expression at TC ≥50% was approximately 22% [40]. In a pooled analysis of tumor tissue samples from three KEYNOTE clinical trials assessing pembrolizumab efficacy and safety in patients with advanced NSCLC, PD-L1 expression at TC ≥50% was found in 28% of tumors [41]. However, in a study in Australia in patients with surgically resected early stage NSCLC (stages I–III), high PD-L1 expression (defined as tumors with ≥50% cells showing positive membrane staining with a monoclonal anti-PD-L1 antibody) was observed in only 7.4% of tumors; though PD-L1 staining in ≥1% of TCs and ≥5% of TCs was identified in 28% and 20% of cases [42]. Taken together, despite varying cutoffs, these reports suggest variability in PD-L1 expression, which may be related to the techniques used to measure PD-L1 levels or inherent variability in PD-L1 expression among different NSCLC cohorts.

We found no association between PD-L1 expression on TCs or ICs and OS across stages. This is in contrast to findings in an Australian study of patients with surgically resected early-stage NSCLC (n = 681), that high PD-L1 tumor expression (TC ≥50%) was associated with longer OS compared with low PD-L1 tumor expression (113.2 months versus 85.5 months) [42]. Of note, only a subset of patients in the latter study was expected to have received adjuvant chemotherapy. Conflicting findings have also been observed in advanced NSCLC. In a recent review of patients with advanced/metastatic NSCLC, PD-L1-TC expression was found to be associated with shorter OS in most of the studies evaluated [33]. Conversely, a study in advanced NSCLC populations from Denmark observed no association between PD-L1 expression (TC ≥50%) and OS [38]. The discrepancy in the survival outcomes with PD-L1 expression may be because of the differences in the patient populations and assay antibodies used in the studies. While analytical comparisons have demonstrated a reasonable agreement among most of the available PD-L1 detection assays (VENTANA PD-L1 [SP263] Assay, Dako PD-L1 IHC 22C3 pharmDx, and Dako PD-L1 IHC 28–8 pharmDx) [28], lower sensitivity has been reported with the VENTANA PD-L1 (SP142) Assay for determining tumor proportion scores on TCs in comparison with other assays [43]. However, none of the published studies have used the VENTANA PD-L1 (SP263) Assay, and in the current study, this assay had a very low failure rate (<1%), potentially because of the stringent requirements for adequate TC content in the tumor tissue samples tested.

Unlike in the current study, a few reports [36,44], including one in an NSCLC patient population specifically selected for EGFR mutations [44], have found an association between EGFR mutations and PD-L1 expression. As the prevalence of EGFR mutations in the current study population was low (3.6%), the study did not detect any potential associations between PD-L1 and EGFR. While we found that 29% of tumors had KRAS mutations, in other studies of surgically resected early-stage NSCLC, KRAS mutations have been reported at a lower frequency of 17%–20% [45]. A pooled analysis of studies among patients with resected early-stage NSCLC treated with adjuvant chemotherapy identified KRAS mutations in 19% of patient specimens [46]. We extended these findings by also evaluating the association of KRAS mutations with PD-L1 expression and found that KRAS mutations were more likely to be present in tumors with PD-L1 TC ≥25%.

Earlier reports indicate that the presence of tumor infiltration with lymphocytes favors a positive prognosis and improved survival in cancer, including patients with NSCLC in the adjuvant chemotherapy setting [47,48]. In the current exploratory analyses, increasing tumor infiltration with ICs was associated with a modest per-unit prognostic impact among patients requiring adjuvant chemotherapy for stage II and IIIA disease.

Our study had some limitations. Owing to the small number of patients with EGFR or KRAS mutations or those expressing PD-L1 above the cutoffs, careful interpretation of the biomarker status and related outcomes is warranted. Furthermore, there were too few patients with stage IB NSCLC receiving adjuvant therapy to draw any firm conclusions. Detailed information on adjuvant chemotherapy regimens was not available from the registry. PD-L1 TC was scored at a 25% TC cutoff only, therefore limiting comparison with other studies. The survival analyses were not adjusted for ECOG PS and smoking status because of a large proportion of missing data. Additionally, during the follow-up period, neither checkpoint inhibitors nor EGFR tyrosine kinase inhibitors were approved as adjuvant therapy. Only first-generation EGFR-targeting therapies were approved for the treatment of metastatic disease at the time of the study.

This study exhibits several strengths. Danish health registries are some of the world’s oldest registry systems and are used extensively for research [49]. Advantages of using these registries include a nationalized, free healthcare system with uniform disease and procedure registration and coding, and the ability to link and collect data on a given patient from multiple registries, resulting in a complete and unbiased follow-up for all cohort members [49].

Findings from this observational study suggest that OS of patients with NSCLC who received adjuvant chemotherapy is not associated with PD-L1 expression in TCs or ICs. KRAS mutations were more likely to be present in tumors with PD-L1 TC ≥25% compared with those with PD-L1 TC <25%, however, there was no prognostic impact observed with the presence of KRAS or EGFR mutations.

Supporting information

S1 Fig. Network of population-based medical registries linkable on an individual level via the CPR number.

https://doi.org/10.1371/journal.pone.0284037.s001

(DOCX)

S1 Table. Kaplan-Meier estimates of 25% survival (months, 95% CI) by biomarker status in patients with stage II or stage IIIA NSCLC receiving adjuvant chemotherapy.

https://doi.org/10.1371/journal.pone.0284037.s002

(DOCX)

S2 Table. PD-L1 expression level by EGFR and KRAS mutation status in patients with stages II, and IIIA NSCLC receiving adjuvant chemotherapy.

https://doi.org/10.1371/journal.pone.0284037.s003

(DOCX)

Acknowledgments

The authors thank Suzanne Booth, Nicola Lawson, and Noolie Gregory for their valuable contribution to the study.

Medical writing support, in accordance with the Good Publication Practice (GPP3) guidelines, was provided by Kaveri Sidhu, PhD, of Cactus Life Sciences (part of Cactus Communications Pvt. Ltd.), Mumbai, India and funded by AstraZeneca.

References

1. Bray F, Ferlay J, Soerjomataram I, et al. Global cancer statistics 2018: GLOBOCAN estimates of incidence and mortality worldwide for 36 cancers in 185 countries. CA Cancer J Clin. 2018;68: 394–424. pmid:30207593
- View Article
- PubMed/NCBI
- Google Scholar
2. De Angelis R, Sant M, Coleman MP, et al; EUROCARE-5 Working Group. Cancer survival in Europe 1999–2007 by country and age: results of EUROCARE—5-a population-based study. Lancet Oncol. 2014;15: 23–34. pmid:24314615
- View Article
- PubMed/NCBI
- Google Scholar
3. Danckert B, Ferlay J, Engholm G, et al. NORDCAN: Cancer Incidence, Mortality, Prevalence and Survival in the Nordic Countries, Version 8.2 (26.03.2019). Association of the Nordic Cancer Registries. Danish Cancer Society. https://www-dep.iarc.fr/NORDCAN/english/frame.asp. Accessed 15 June 2020.
4. Herbst RS, Morgensztern D, Boshoff C. The biology and management of non-small cell lung cancer. Nature. 2018;553: 446–454. pmid:29364287
- View Article
- PubMed/NCBI
- Google Scholar
5. Postmus PE, Kerr KM, Oudkerk M, et al; ESMO Guidelines Committee. Early and locally advanced non-small-cell lung cancer (NSCLC): ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up. Ann Oncol. 2017;28(suppl 4): iv1–iv21. pmid:28881918
- View Article
- PubMed/NCBI
- Google Scholar
6. Rud AK, Borgen E, Mælandsmo GM, et al. Clinical significance of disseminated tumour cells in non-small cell lung cancer. Br J Cancer. 2013;109: 1264–1270. pmid:23942067
- View Article
- PubMed/NCBI
- Google Scholar
7. Pisters KM, Le Chevalier T. Adjuvant chemotherapy in completely resected non-small-cell lung cancer. J Clin Oncol. 2005;23: 3270–3278. Erratum in: J Clin Oncol. 2008;26: 2238. pmid:15886314
- View Article
- PubMed/NCBI
- Google Scholar
8. Uramoto H, Tanaka F. Recurrence after surgery in patients with NSCLC. Transl Lung Cancer Res. 2014;3: 242–249. pmid:25806307
- View Article
- PubMed/NCBI
- Google Scholar
9. Mielgo-Rubio X., et al. Immunotherapy in non-small cell lung cancer: Update and new insights. J Clin Transl Res. 2021 Jan 20;7(1): 1–21. http://dx.doi.org/10.18053/jctres.07.202101.001. pmid:34104805
- View Article
- PubMed/NCBI
- Google Scholar
10. Rocco D., et al. Pharmacodynamics of current and emerging PD-1 and PD-L1 inhibitors for the treatment of non-small cell lung cancer. Review Expert Opin Drug Metab Toxicol. 2020 Feb;16(2): 87–96. pmid:31978315
- View Article
- PubMed/NCBI
- Google Scholar
11. Gandhi L, Rodríguez-Abreu D, Gadgeel S, et al. Pembrolizumab plus chemotherapy in metastatic non–small-cell lung cancer. N Engl J Med. 2018;378: 2078–2092. pmid:29658856
- View Article
- PubMed/NCBI
- Google Scholar
12. Antonia SJ, Villegas A, Daniel D, et al. Overall survival with durvalumab after chemoradiotherapy in stage III NSCLC. N Engl J Med. 2018;379: 2342–2350. pmid:30280658
- View Article
- PubMed/NCBI
- Google Scholar
13. Nakanishi J, Wada Y, Matsumoto K, et al. Overexpression of B7-H1 (PD-L1) significantly associates with tumor grade and postoperative prognosis in human urothelial cancers. Cancer Immunol Immunother. 2007;56: 1173–1182. pmid:17186290
- View Article
- PubMed/NCBI
- Google Scholar
14. Nomi T, Sho M, Akahori T, et al. Clinical significance and therapeutic potential of the programmed death-1 ligand/programmed death-1 pathway in human pancreatic cancer. Clin Cancer Res. 2007;13: 2151–2157. pmid:17404099
- View Article
- PubMed/NCBI
- Google Scholar
15. Zeng Z, Shi F, Zhou L, et al. Upregulation of circulating PD-L1/PD-1 is associated with poor post-cryoablation prognosis in patients with HBV-related hepatocellular carcinoma. PLoS One. 2011;6: e23621. pmid:21912640
- View Article
- PubMed/NCBI
- Google Scholar
16. Hino R, Kabashima K, Kato Y, et al. Tumor cell expression of programmed cell death-1 ligand 1 is a prognostic factor for malignant melanoma. Cancer. 2010;116: 1757–1766. pmid:20143437
- View Article
- PubMed/NCBI
- Google Scholar
17. Hamanishi J, Mandai M, Iwasaki M, et al. Programmed cell death 1 ligand 1 and tumor-infiltrating CD8+ T lymphocytes are prognostic factors of human ovarian cancer. Proc Natl Acad Sci U S A. 2007;104: 3360–3365. pmid:17360651
- View Article
- PubMed/NCBI
- Google Scholar
18. Pao W, Girard N. New driver mutations in non-small-cell lung cancer. Lancet Oncol. 2011;12: 175–180. pmid:21277552
- View Article
- PubMed/NCBI
- Google Scholar
19. Suda K, Onozato R, Yatabe Y, et al. EGFR T790M mutation: a double role in lung cancer cell survival? J Thorac Oncol. 2009;4: 1–4. pmid:19096299
- View Article
- PubMed/NCBI
- Google Scholar
20. Ota K, Azuma K, Kawahara A, et al. Induction of PD-L1 expression by the EML4-ALK oncoprotein and downstream signaling pathways in non-small cell lung cancer. Clin Cancer Res. 2015;21: 4014–4021. pmid:26019170
- View Article
- PubMed/NCBI
- Google Scholar
21. Gjerstorff ML. The Danish Cancer Registry. Scand J Public Health. 2011;39: 42–45. pmid:21775350
- View Article
- PubMed/NCBI
- Google Scholar
22. Storm HH, Michelsen EV, Clemmensen IH, et al. The Danish Cancer Registry—history, content, quality and use. Dan Med Bull. 1997;44: 535–539. pmid:9408738
- View Article
- PubMed/NCBI
- Google Scholar
23. Jakobsen E, Rasmussen TR. The Danish Lung Cancer Registry. Clin Epidemiol. 2016;8: 537–541. pmid:27822096
- View Article
- PubMed/NCBI
- Google Scholar
24. Schmidt M, Schmidt SA, Sandegaard JL, et al. The Danish National Patient Registry: a review of content, data quality, and research potential. Clin Epidemiol. 2015;7: 449–490. pmid:26604824
- View Article
- PubMed/NCBI
- Google Scholar
25. Andersen TF, Madsen M, Jørgensen J, et al. The Danish National Hospital Register. A valuable source of data for modern health sciences. Dan Med Bull. 1999;46: 263–268. pmid:10421985
- View Article
- PubMed/NCBI
- Google Scholar
26. Erichsen R, Lash TL, Hamilton-Dutoit SJ, et al. Existing data sources for clinical epidemiology: the Danish National Pathology Registry and Data Bank. Clin Epidemiol. 2010;2: 51–56. pmid:20865103
- View Article
- PubMed/NCBI
- Google Scholar
27. Schmidt M, Pedersen L, Sørensen HT. The Danish Civil Registration System as a tool in epidemiology. Eur J Epidemiol. 2014;29: 541–549. pmid:24965263
- View Article
- PubMed/NCBI
- Google Scholar
28. Hirsch FR, McElhinny A, Stanforth D, et al. PD-L1 immunohistochemistry assays for lung cancer: results from phase 1 of the Blueprint PD-L1 IHC Assay Comparison Project. J Thorac Oncol. 2017;12: 208–222. pmid:27913228
- View Article
- PubMed/NCBI
- Google Scholar
29. Rebelatto MC, Midha A, Mistry A, et al. Development of a programmed cell death ligand-1 immunohistochemical assay validated for analysis of non-small cell lung cancer and head and neck squamous cell carcinoma. Diagn Pathol. 2016;11: 95. pmid:27717372
- View Article
- PubMed/NCBI
- Google Scholar
30. ClinicalTrials.gov. Double Blind Placebo Controlled Controlled Study of Adjuvant MEDI4736 In Completely Resected NSCLC. ClinicalTrials.gov Identifier: NCT02273375. https://clinicaltrials.gov/ct2/show/NCT02273375. Accessed May 04, 2022.
31. Chouaid C, Danson S, Andreas S, et al. Adjuvant treatment patterns and outcomes in patients with stage IB-IIIA non-small cell lung cancer in France, Germany, and the United Kingdom based on the LuCaBIS burden of illness study. Lung Cancer. 2018;124: 310–316. pmid:30119925
- View Article
- PubMed/NCBI
- Google Scholar
32. Osler M, Prescott E, Gottschau A, et al. Trends in smoking prevalence in Danish adults, 1964–1994. The influence of gender, age, and education. Scand J Soc Med. 1998;26: 293–298. pmid:9868755
- View Article
- PubMed/NCBI
- Google Scholar
33. Brody R, Zhang Y, Ballas M, et al. PD-L1 expression in advanced NSCLC: insights into risk stratification and treatment selection from a systematic literature review. Lung Cancer. 2017;112: 200–215. pmid:29191596
- View Article
- PubMed/NCBI
- Google Scholar
34. Yang CY, Lin MW, Chang YL, et al. Programmed cell death-ligand 1 expression in surgically resected stage I pulmonary adenocarcinoma and its correlation with driver mutations and clinical outcomes. Eur J Cancer. 2014;50: 1361–1369. pmid:24548766
- View Article
- PubMed/NCBI
- Google Scholar
35. Zhang Y, Wang L, Li Y, et al. Protein expression of programmed death 1 ligand 1 and ligand 2 independently predict poor prognosis in surgically resected lung adenocarcinoma. Onco Targets Ther. 2014;7: 567–573. pmid:24748806
- View Article
- PubMed/NCBI
- Google Scholar
36. D’Incecco A, Andreozzi M, Ludovini V, et al. PD-1 and PD-L1 expression in molecularly selected non-small-cell lung cancer patients. Br J Cancer. 2015;112: 95–102. pmid:25349974
- View Article
- PubMed/NCBI
- Google Scholar
37. Sun JM, Zhou W, Choi YL, et al. Prognostic significance of PD-L1 in patients with non-small cell lung cancer: a large cohort study of surgically resected cases. J Thorac Oncol. 2016;11: 1003–1011. pmid:27103510
- View Article
- PubMed/NCBI
- Google Scholar
38. Sorensen SF, Zhou W, Dolled-Filhart M, et al. PD-L1 expression and survival among patients with advanced non-small cell lung cancer treated with chemotherapy. Transl Oncol. 2016;9: 64–69. pmid:26947883
- View Article
- PubMed/NCBI
- Google Scholar
39. Zhang J, Gao J, Li Y, et al. Circulating PD-L1 in NSCLC patients and the correlation between the level of PD-L1 expression and the clinical characteristics. Thorac Cancer. 2015;6: 534–538. pmid:26273411
- View Article
- PubMed/NCBI
- Google Scholar
40. Dietel M, Savelov N, Salanova R, et al. Real-world prevalence of PD-L1 expression in locally advanced or metastatic non-small cell lung cancer (NSCLC): the global, multicentre EXPRESS study. J Thorac Oncol. 2018;13(suppl): S74–S75. https://doi.org/10.1016/S1556-0864(18)30404-0.
- View Article
- Google Scholar
41. Aggarwal C, Rodriguez Abreu D, Felip E, et al. Prevalence of PD-L1 expression in patients with non-small cell lung cancer screened for enrollment in KEYNOTE-001, -010, and -024. Ann Oncol. 2016;27(suppl 6): 1060P. https://doi.org/10.1093/annonc/mdw378.14.
- View Article
- Google Scholar
42. Cooper WA, Tran T, Vilain RE, et al. PD-L1 expression is a favorable prognostic factor in early stage non-small cell carcinoma. Lung Cancer. 2015;89: 181–188. pmid:26024796
- View Article
- PubMed/NCBI
- Google Scholar
43. Tsao MS, Kerr KM, Kockx M, et al. PD-L1 immunohistochemistry comparability study in real-life clinical samples: results of Blueprint phase 2 project. J Thorac Oncol. 2018;13: 1302–1311. pmid:29800747
- View Article
- PubMed/NCBI
- Google Scholar
44. Rojas L, Cardona AF, Arrieta O, et al. PD expression in metastatic non-small cell lung cancer patients from Colombia (CLICAP). J Thorac Oncol. 2014;9(suppl 3): S199–S200.
- View Article
- Google Scholar
45. Pan W, Yang Y, Zhu H, et al. KRAS mutation is a weak, but valid predictor for poor prognosis and treatment outcomes in NSCLC: a meta-analysis of 41 studies. Oncotarget. 2016;7: 8373–8388. pmid:26840022
- View Article
- PubMed/NCBI
- Google Scholar
46. Shepherd FA, Domerg C, Hainaut P, et al. Pooled analysis of the prognostic and predictive effects of KRAS mutation status and KRAS mutation subtype in early-stage resected non-small-cell lung cancer in four trials of adjuvant chemotherapy. J Clin Oncol. 2013;31: 2173–2181. https://doi.org/10.1200/JCO.2012.48.1390.
- View Article
- Google Scholar
47. Gooden MJ, de Bock GH, Leffers N, et al. The prognostic influence of tumour-infiltrating lymphocytes in cancer: a systematic review with meta-analysis. Br J Cancer. 2011;105: 93–103. pmid:21629244
- View Article
- PubMed/NCBI
- Google Scholar
48. Ishii H, Azuma K, Kawahara A, et al. Programmed cell death-ligand 1 expression and immunoscore in stage II and III non-small cell lung cancer patients receiving adjuvant chemotherapy. Oncotarget. 2017;8: 61618–61625. pmid:28977890
- View Article
- PubMed/NCBI
- Google Scholar
49. Epidemiology Frank L. When an entire country is a cohort. Science. 2000;287: 2398–2399. https://doi.org/10.1126/science.287.5462.2398.
- View Article
- Google Scholar

[ref1] 1. Bray F, Ferlay J, Soerjomataram I, et al. Global cancer statistics 2018: GLOBOCAN estimates of incidence and mortality worldwide for 36 cancers in 185 countries. CA Cancer J Clin. 2018;68: 394–424. pmid:30207593
View Article
PubMed/NCBI
Google Scholar

[2] View Article

[3] PubMed/NCBI

[4] Google Scholar

[ref2] 2. De Angelis R, Sant M, Coleman MP, et al; EUROCARE-5 Working Group. Cancer survival in Europe 1999–2007 by country and age: results of EUROCARE—5-a population-based study. Lancet Oncol. 2014;15: 23–34. pmid:24314615
View Article
PubMed/NCBI
Google Scholar

[6] View Article

[7] PubMed/NCBI

[8] Google Scholar

[ref3] 3. Danckert B, Ferlay J, Engholm G, et al. NORDCAN: Cancer Incidence, Mortality, Prevalence and Survival in the Nordic Countries, Version 8.2 (26.03.2019). Association of the Nordic Cancer Registries. Danish Cancer Society. https://www-dep.iarc.fr/NORDCAN/english/frame.asp. Accessed 15 June 2020.

[ref4] 4. Herbst RS, Morgensztern D, Boshoff C. The biology and management of non-small cell lung cancer. Nature. 2018;553: 446–454. pmid:29364287
View Article
PubMed/NCBI
Google Scholar

[11] View Article

[12] PubMed/NCBI

[13] Google Scholar

[ref5] 5. Postmus PE, Kerr KM, Oudkerk M, et al; ESMO Guidelines Committee. Early and locally advanced non-small-cell lung cancer (NSCLC): ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up. Ann Oncol. 2017;28(suppl 4): iv1–iv21. pmid:28881918
View Article
PubMed/NCBI
Google Scholar

[15] View Article

[16] PubMed/NCBI

[17] Google Scholar

[ref6] 6. Rud AK, Borgen E, Mælandsmo GM, et al. Clinical significance of disseminated tumour cells in non-small cell lung cancer. Br J Cancer. 2013;109: 1264–1270. pmid:23942067
View Article
PubMed/NCBI
Google Scholar

[19] View Article

[20] PubMed/NCBI

[21] Google Scholar

[ref7] 7. Pisters KM, Le Chevalier T. Adjuvant chemotherapy in completely resected non-small-cell lung cancer. J Clin Oncol. 2005;23: 3270–3278. Erratum in: J Clin Oncol. 2008;26: 2238. pmid:15886314
View Article
PubMed/NCBI
Google Scholar

[23] View Article

[24] PubMed/NCBI

[25] Google Scholar

[ref8] 8. Uramoto H, Tanaka F. Recurrence after surgery in patients with NSCLC. Transl Lung Cancer Res. 2014;3: 242–249. pmid:25806307
View Article
PubMed/NCBI
Google Scholar

[27] View Article

[28] PubMed/NCBI

[29] Google Scholar

[ref9] 9. Mielgo-Rubio X., et al. Immunotherapy in non-small cell lung cancer: Update and new insights. J Clin Transl Res. 2021 Jan 20;7(1): 1–21. http://dx.doi.org/10.18053/jctres.07.202101.001. pmid:34104805
View Article
PubMed/NCBI
Google Scholar

[31] View Article

[32] PubMed/NCBI

[33] Google Scholar

[ref10] 10. Rocco D., et al. Pharmacodynamics of current and emerging PD-1 and PD-L1 inhibitors for the treatment of non-small cell lung cancer. Review Expert Opin Drug Metab Toxicol. 2020 Feb;16(2): 87–96. pmid:31978315
View Article
PubMed/NCBI
Google Scholar

[35] View Article

[36] PubMed/NCBI

[37] Google Scholar

[ref11] 11. Gandhi L, Rodríguez-Abreu D, Gadgeel S, et al. Pembrolizumab plus chemotherapy in metastatic non–small-cell lung cancer. N Engl J Med. 2018;378: 2078–2092. pmid:29658856
View Article
PubMed/NCBI
Google Scholar

[39] View Article

[40] PubMed/NCBI

[41] Google Scholar

[ref12] 12. Antonia SJ, Villegas A, Daniel D, et al. Overall survival with durvalumab after chemoradiotherapy in stage III NSCLC. N Engl J Med. 2018;379: 2342–2350. pmid:30280658
View Article
PubMed/NCBI
Google Scholar

[43] View Article

[44] PubMed/NCBI

[45] Google Scholar

[ref13] 13. Nakanishi J, Wada Y, Matsumoto K, et al. Overexpression of B7-H1 (PD-L1) significantly associates with tumor grade and postoperative prognosis in human urothelial cancers. Cancer Immunol Immunother. 2007;56: 1173–1182. pmid:17186290
View Article
PubMed/NCBI
Google Scholar

[47] View Article

[48] PubMed/NCBI

[49] Google Scholar

[ref14] 14. Nomi T, Sho M, Akahori T, et al. Clinical significance and therapeutic potential of the programmed death-1 ligand/programmed death-1 pathway in human pancreatic cancer. Clin Cancer Res. 2007;13: 2151–2157. pmid:17404099
View Article
PubMed/NCBI
Google Scholar

[51] View Article

[52] PubMed/NCBI

[53] Google Scholar

[ref15] 15. Zeng Z, Shi F, Zhou L, et al. Upregulation of circulating PD-L1/PD-1 is associated with poor post-cryoablation prognosis in patients with HBV-related hepatocellular carcinoma. PLoS One. 2011;6: e23621. pmid:21912640
View Article
PubMed/NCBI
Google Scholar

[55] View Article

[56] PubMed/NCBI

[57] Google Scholar

[ref16] 16. Hino R, Kabashima K, Kato Y, et al. Tumor cell expression of programmed cell death-1 ligand 1 is a prognostic factor for malignant melanoma. Cancer. 2010;116: 1757–1766. pmid:20143437
View Article
PubMed/NCBI
Google Scholar

[59] View Article

[60] PubMed/NCBI

[61] Google Scholar

[ref17] 17. Hamanishi J, Mandai M, Iwasaki M, et al. Programmed cell death 1 ligand 1 and tumor-infiltrating CD8+ T lymphocytes are prognostic factors of human ovarian cancer. Proc Natl Acad Sci U S A. 2007;104: 3360–3365. pmid:17360651
View Article
PubMed/NCBI
Google Scholar

[63] View Article

[64] PubMed/NCBI

[65] Google Scholar

[ref18] 18. Pao W, Girard N. New driver mutations in non-small-cell lung cancer. Lancet Oncol. 2011;12: 175–180. pmid:21277552
View Article
PubMed/NCBI
Google Scholar

[67] View Article

[68] PubMed/NCBI

[69] Google Scholar

[ref19] 19. Suda K, Onozato R, Yatabe Y, et al. EGFR T790M mutation: a double role in lung cancer cell survival? J Thorac Oncol. 2009;4: 1–4. pmid:19096299
View Article
PubMed/NCBI
Google Scholar

[71] View Article

[72] PubMed/NCBI

[73] Google Scholar

[ref20] 20. Ota K, Azuma K, Kawahara A, et al. Induction of PD-L1 expression by the EML4-ALK oncoprotein and downstream signaling pathways in non-small cell lung cancer. Clin Cancer Res. 2015;21: 4014–4021. pmid:26019170
View Article
PubMed/NCBI
Google Scholar

[75] View Article

[76] PubMed/NCBI

[77] Google Scholar

[ref21] 21. Gjerstorff ML. The Danish Cancer Registry. Scand J Public Health. 2011;39: 42–45. pmid:21775350
View Article
PubMed/NCBI
Google Scholar

[79] View Article

[80] PubMed/NCBI

[81] Google Scholar

[ref22] 22. Storm HH, Michelsen EV, Clemmensen IH, et al. The Danish Cancer Registry—history, content, quality and use. Dan Med Bull. 1997;44: 535–539. pmid:9408738
View Article
PubMed/NCBI
Google Scholar

[83] View Article

[84] PubMed/NCBI

[85] Google Scholar

[ref23] 23. Jakobsen E, Rasmussen TR. The Danish Lung Cancer Registry. Clin Epidemiol. 2016;8: 537–541. pmid:27822096
View Article
PubMed/NCBI
Google Scholar

[87] View Article

[88] PubMed/NCBI

[89] Google Scholar

[ref24] 24. Schmidt M, Schmidt SA, Sandegaard JL, et al. The Danish National Patient Registry: a review of content, data quality, and research potential. Clin Epidemiol. 2015;7: 449–490. pmid:26604824
View Article
PubMed/NCBI
Google Scholar

[91] View Article

[92] PubMed/NCBI

[93] Google Scholar

[ref25] 25. Andersen TF, Madsen M, Jørgensen J, et al. The Danish National Hospital Register. A valuable source of data for modern health sciences. Dan Med Bull. 1999;46: 263–268. pmid:10421985
View Article
PubMed/NCBI
Google Scholar

[95] View Article

[96] PubMed/NCBI

[97] Google Scholar

[ref26] 26. Erichsen R, Lash TL, Hamilton-Dutoit SJ, et al. Existing data sources for clinical epidemiology: the Danish National Pathology Registry and Data Bank. Clin Epidemiol. 2010;2: 51–56. pmid:20865103
View Article
PubMed/NCBI
Google Scholar

[99] View Article

[100] PubMed/NCBI

[101] Google Scholar

[ref27] 27. Schmidt M, Pedersen L, Sørensen HT. The Danish Civil Registration System as a tool in epidemiology. Eur J Epidemiol. 2014;29: 541–549. pmid:24965263
View Article
PubMed/NCBI
Google Scholar

[103] View Article

[104] PubMed/NCBI

[105] Google Scholar

[ref28] 28. Hirsch FR, McElhinny A, Stanforth D, et al. PD-L1 immunohistochemistry assays for lung cancer: results from phase 1 of the Blueprint PD-L1 IHC Assay Comparison Project. J Thorac Oncol. 2017;12: 208–222. pmid:27913228
View Article
PubMed/NCBI
Google Scholar

[107] View Article

[108] PubMed/NCBI

[109] Google Scholar

[ref29] 29. Rebelatto MC, Midha A, Mistry A, et al. Development of a programmed cell death ligand-1 immunohistochemical assay validated for analysis of non-small cell lung cancer and head and neck squamous cell carcinoma. Diagn Pathol. 2016;11: 95. pmid:27717372
View Article
PubMed/NCBI
Google Scholar

[111] View Article

[112] PubMed/NCBI

[113] Google Scholar

[ref30] 30. ClinicalTrials.gov. Double Blind Placebo Controlled Controlled Study of Adjuvant MEDI4736 In Completely Resected NSCLC. ClinicalTrials.gov Identifier: NCT02273375. https://clinicaltrials.gov/ct2/show/NCT02273375. Accessed May 04, 2022.

[ref31] 31. Chouaid C, Danson S, Andreas S, et al. Adjuvant treatment patterns and outcomes in patients with stage IB-IIIA non-small cell lung cancer in France, Germany, and the United Kingdom based on the LuCaBIS burden of illness study. Lung Cancer. 2018;124: 310–316. pmid:30119925
View Article
PubMed/NCBI
Google Scholar

[116] View Article

[117] PubMed/NCBI

[118] Google Scholar

[ref32] 32. Osler M, Prescott E, Gottschau A, et al. Trends in smoking prevalence in Danish adults, 1964–1994. The influence of gender, age, and education. Scand J Soc Med. 1998;26: 293–298. pmid:9868755
View Article
PubMed/NCBI
Google Scholar

[120] View Article

[121] PubMed/NCBI

[122] Google Scholar

[ref33] 33. Brody R, Zhang Y, Ballas M, et al. PD-L1 expression in advanced NSCLC: insights into risk stratification and treatment selection from a systematic literature review. Lung Cancer. 2017;112: 200–215. pmid:29191596
View Article
PubMed/NCBI
Google Scholar

[124] View Article

[125] PubMed/NCBI

[126] Google Scholar

[ref34] 34. Yang CY, Lin MW, Chang YL, et al. Programmed cell death-ligand 1 expression in surgically resected stage I pulmonary adenocarcinoma and its correlation with driver mutations and clinical outcomes. Eur J Cancer. 2014;50: 1361–1369. pmid:24548766
View Article
PubMed/NCBI
Google Scholar

[128] View Article

[129] PubMed/NCBI

[130] Google Scholar

[ref35] 35. Zhang Y, Wang L, Li Y, et al. Protein expression of programmed death 1 ligand 1 and ligand 2 independently predict poor prognosis in surgically resected lung adenocarcinoma. Onco Targets Ther. 2014;7: 567–573. pmid:24748806
View Article
PubMed/NCBI
Google Scholar

[132] View Article

[133] PubMed/NCBI

[134] Google Scholar

[ref36] 36. D’Incecco A, Andreozzi M, Ludovini V, et al. PD-1 and PD-L1 expression in molecularly selected non-small-cell lung cancer patients. Br J Cancer. 2015;112: 95–102. pmid:25349974
View Article
PubMed/NCBI
Google Scholar

[136] View Article

[137] PubMed/NCBI

[138] Google Scholar

[ref37] 37. Sun JM, Zhou W, Choi YL, et al. Prognostic significance of PD-L1 in patients with non-small cell lung cancer: a large cohort study of surgically resected cases. J Thorac Oncol. 2016;11: 1003–1011. pmid:27103510
View Article
PubMed/NCBI
Google Scholar

[140] View Article

[141] PubMed/NCBI

[142] Google Scholar

[ref38] 38. Sorensen SF, Zhou W, Dolled-Filhart M, et al. PD-L1 expression and survival among patients with advanced non-small cell lung cancer treated with chemotherapy. Transl Oncol. 2016;9: 64–69. pmid:26947883
View Article
PubMed/NCBI
Google Scholar

[144] View Article

[145] PubMed/NCBI

[146] Google Scholar

[ref39] 39. Zhang J, Gao J, Li Y, et al. Circulating PD-L1 in NSCLC patients and the correlation between the level of PD-L1 expression and the clinical characteristics. Thorac Cancer. 2015;6: 534–538. pmid:26273411
View Article
PubMed/NCBI
Google Scholar

[148] View Article

[149] PubMed/NCBI

[150] Google Scholar

[ref40] 40. Dietel M, Savelov N, Salanova R, et al. Real-world prevalence of PD-L1 expression in locally advanced or metastatic non-small cell lung cancer (NSCLC): the global, multicentre EXPRESS study. J Thorac Oncol. 2018;13(suppl): S74–S75. https://doi.org/10.1016/S1556-0864(18)30404-0.
View Article
Google Scholar

[152] View Article

[153] Google Scholar

[ref41] 41. Aggarwal C, Rodriguez Abreu D, Felip E, et al. Prevalence of PD-L1 expression in patients with non-small cell lung cancer screened for enrollment in KEYNOTE-001, -010, and -024. Ann Oncol. 2016;27(suppl 6): 1060P. https://doi.org/10.1093/annonc/mdw378.14.
View Article
Google Scholar

[155] View Article

[156] Google Scholar

[ref42] 42. Cooper WA, Tran T, Vilain RE, et al. PD-L1 expression is a favorable prognostic factor in early stage non-small cell carcinoma. Lung Cancer. 2015;89: 181–188. pmid:26024796
View Article
PubMed/NCBI
Google Scholar

[158] View Article

[159] PubMed/NCBI

[160] Google Scholar

[ref43] 43. Tsao MS, Kerr KM, Kockx M, et al. PD-L1 immunohistochemistry comparability study in real-life clinical samples: results of Blueprint phase 2 project. J Thorac Oncol. 2018;13: 1302–1311. pmid:29800747
View Article
PubMed/NCBI
Google Scholar

[162] View Article

[163] PubMed/NCBI

[164] Google Scholar

[ref44] 44. Rojas L, Cardona AF, Arrieta O, et al. PD expression in metastatic non-small cell lung cancer patients from Colombia (CLICAP). J Thorac Oncol. 2014;9(suppl 3): S199–S200.
View Article
Google Scholar

[166] View Article

[167] Google Scholar

[ref45] 45. Pan W, Yang Y, Zhu H, et al. KRAS mutation is a weak, but valid predictor for poor prognosis and treatment outcomes in NSCLC: a meta-analysis of 41 studies. Oncotarget. 2016;7: 8373–8388. pmid:26840022
View Article
PubMed/NCBI
Google Scholar

[169] View Article

[170] PubMed/NCBI

[171] Google Scholar

[ref46] 46. Shepherd FA, Domerg C, Hainaut P, et al. Pooled analysis of the prognostic and predictive effects of KRAS mutation status and KRAS mutation subtype in early-stage resected non-small-cell lung cancer in four trials of adjuvant chemotherapy. J Clin Oncol. 2013;31: 2173–2181. https://doi.org/10.1200/JCO.2012.48.1390.
View Article
Google Scholar

[173] View Article

[174] Google Scholar

[ref47] 47. Gooden MJ, de Bock GH, Leffers N, et al. The prognostic influence of tumour-infiltrating lymphocytes in cancer: a systematic review with meta-analysis. Br J Cancer. 2011;105: 93–103. pmid:21629244
View Article
PubMed/NCBI
Google Scholar

[176] View Article

[177] PubMed/NCBI

[178] Google Scholar

[ref48] 48. Ishii H, Azuma K, Kawahara A, et al. Programmed cell death-ligand 1 expression and immunoscore in stage II and III non-small cell lung cancer patients receiving adjuvant chemotherapy. Oncotarget. 2017;8: 61618–61625. pmid:28977890
View Article
PubMed/NCBI
Google Scholar

[180] View Article

[181] PubMed/NCBI

[182] Google Scholar

[ref49] 49. Epidemiology Frank L. When an entire country is a cohort. Science. 2000;287: 2398–2399. https://doi.org/10.1126/science.287.5462.2398.
View Article
Google Scholar

[184] View Article

[185] Google Scholar

Figures

Abstract

Introduction

Methods

Results

Conclusion

Introduction

Methods

Study design and patients

Tumor samples and biomarker assessment

Study variables and covariates

Statistical analysis

Results

PD-L1 expression

Overall Survival by PD-L1 expression level

EGFR mutation status

KRAS mutation status

Overall Survival by EGFR and KRAS mutations

Association of PD-L1 expression levels with EGFR and KRAS mutations

Discussion

Supporting information

S1 Fig. Network of population-based medical registries linkable on an individual level via the CPR number.

S1 Table. Kaplan-Meier estimates of 25% survival (months, 95% CI) by biomarker status in patients with stage II or stage IIIA NSCLC receiving adjuvant chemotherapy.

S2 Table. PD-L1 expression level by EGFR and KRAS mutation status in patients with stages II, and IIIA NSCLC receiving adjuvant chemotherapy.

Acknowledgments

References