The authors have read the journal’s policy and have the following conflicts: Thomas Eigentler and Claus Garbe have received honoraria and travel support from Roche, Ulrike Leiter received travel support. Additionally, Claus Garbe participated in advisory board meetings and received further research support from Roche. This does not alter our adherence to all the PLOS ONE policies on sharing data and materials.
Conceived and designed the experiments: PB CG BW. Performed the experiments: DM SR JB. Analyzed the data: DM UK SR PB CG BW. Contributed reagents/materials/analysis tools: UK SR UL TE JB AP CG. Wrote the paper: DM UK SR UL TE JB AP PB CG BW.
The impact of
We analyzed the mutational status and overall survival of 215 patients receiving treatment with dacarbazine or temozolomide. All patients who started first-line treatment at our institution between 2000 and 2010 were included to prevent selection and bias due to thereafter arising therapeutic options.
No patient received
No differences in prognosis were observed according to the
The aim of the present study was to investigate the prognostic impact of
All patients had given their written informed consent to have clinical data recorded by the Central Malignant Melanoma Registry (CMMR) registry. The institutional ethics committee Tübingen approved the study (ethic vote 047/2013BO2).
Patients with invasive cutaneous melanoma treated at the University Department of Dermatology Tübingen (Germany) were identified in the Central Malignant Melanoma Registry (CMMR) database. Of 319 patients who received first-line systemic treatment with dacarbazine or temozolomide between 2000 and 2010, formalin-fixed paraffin-embedded tumor tissue was available in 219 patients. Data obtained for each patient included gender, age, site of distant metastasis according to the American Joint Committee on Cancer (soft tissue metastasis vs. pulmonary involvement vs. other visceral sites), presence of brain metastasis, serum LDH level (normal vs. >upper limit of normal [ULN]) and the date and cause of death, if applicable. Moreover, time points of initiation of first-line chemotherapy and last follow-up were collected. All patients had given their written informed consent to have their data recorded by the CMMR. The aims and methods of data collection by the CMMR have previously been reported in detail
Microdissection of formalin-fixed paraffin-embedded tumor tissue was performed to obtain at least 50% tumor cells. After digestion by proteinase K an amplicon containing the
Overall survival time was calculated from the first application of temozolomide or dacarbazine to the date of last follow-up or death; only deaths due to melanoma were considered, whereas patients who died from other causes were censored at the date of death. Estimates of cumulative survival probabilities according to Kaplan-Meier were described together with 95%-confidence intervals and compared using log rank tests. Cox regression analyses were used to determine the independent effects of prognostic factors. All variables were considered in Cox regression analyses and patients with missing data were excluded. Models were established using backward and forward stepwise procedures. Remaining non-significant factors were assessed for potential confounding effects. Changes in the estimates of factors in a model by more than 5% were taken as indicative for confounding. Results of the Cox regression models were described by hazard ratios (HR) together with 95%-confidence intervals, and p-values were based on the Wald test. All Chi square tests were performed 2-sided using Fisher’s exact tests. Throughout the analysis, p-values of less than 0.05 were considered statistically significant. All analyses were carried out using SPSS Version 21 (IBM SPSS, Chicago, Illinois, USA).
215 of 219 patients with successful sequencing (98.2%) were further analyzed. Median age was 64 years and 55% were male. The majority of patients (66.0%) were classified as M1c stage according to AJCC at start of systemic treatment (24.2% M1b and 9.8% M1a, respectively). During follow-up, 191 (88.8%) died from melanoma. Median follow-up was 9 months for patients who died and 46 months for those who were alive at the last follow-up. None of the patients received treatment with
After stratification according to the
n | % | Mutational rate | % within |
% within |
p |
1-year survival rate | [95%-CI |
p$ | |
215 | 100% | 41.4% | 43.5% | [36.8; 50.2] | |||||
0.966 | |||||||||
Present | 89 | 41.4% | 43.5% | [33.1; 53.9] | |||||
Absent | 126 | 58.6% | 43.5% | [34.7; 52.3] | |||||
0.071 | 0.071 | ||||||||
Male | 119 | 55.3% | 47.1% | 62.9% | 50.0% | 39.2% | [30.4; 48.0] | ||
Female | 96 | 44.7% | 34.4% | 37.1% | 50.0% | 48.9% | [38.7; 59.0] | ||
0.004 | 0.938 | ||||||||
<50 years | 47 | 21.9% | 59.6% | 31.5% | 15.1% | 39.7% | [25.5; 53.8] | ||
50–59 years | 41 | 19.1% | 51.2% | 23.6% | 15.9% | 45.4% | [30.0; 60.8] | ||
60–69 years | 52 | 24.2% | 34.6% | 20.2% | 27.0% | 45.2% | [31.5; 58.9] | ||
≥70 years | 75 | 34.9% | 29.3% | 24.7% | 42.1% | 43.6% | [32.3; 54.9] | ||
0.008 | 0.146 | ||||||||
Dacarbazine | 143 | 66.5% | 35.0% | 56.2% | 73.8% | 46.3% | [38.1; 54.5] | ||
Temozolomide | 72 | 33.5% | 54.2% | 43.8% | 26.2% | 37.8% | [26.4; 49.2] | ||
0.642 | <0.001 | ||||||||
Elevated | 63 | 32.5% | 38.1% | 30.4% | 33.9% | 23.7% | [12.9; 34.4] | ||
Normal | 131 | 67.5% | 42.0% | 69.6% | 66.1% | 49.1% | [40.5; 57.7] | ||
Missing | 21 | ||||||||
0.307 | <0.001 | ||||||||
Yes | 45 | 20.9% | 48.9% | 24.7% | 18.3% | 18.7% | [7.1; 30.3] | ||
No | 170 | 79.1% | 39.4% | 75.3% | 81.7% | 50.0% | [42.4; 57.6] | ||
0.128 | <0.001 | ||||||||
Soft tissue | 28 | 13.0% | 35.7% | 11.2% | 14.3% | 59.5% | [41.0; 78.0] | ||
Only lung | 59 | 27.4% | 52.5% | 34.8% | 22.2% | 49.2% | [36.4; 61.9] | ||
Other visceral | 128 | 59.5% | 37.5% | 53.9% | 63.5% | 37.4% | [29.0; 45.8] |
95%-CI = 95% confidence interval;
*p-values are results of Fishers exact tests $ p-values are results of log rank tests excluding cases with missing values.
Additionally, correlations were observed between the treatment with temozolomide and younger age (p = 0.001) and between treatment with temozolomide and the presence of brain metastases (p<0.001).
Median overall survival probability according to Kaplan-Meier was 9 months. The presence of brain metastases (
Kaplan Meier survival curves according to (A) the presence of brain metastasis, (B) serum lactate dehydrogenase (LDH) or (C) the
In Cox regression analysis (
Prognostic factor | Sample size (n = 194) | % Dead | Relative risk (95%-CI |
p-value |
Brain metastasis | ||||
No | 153 (78.9%) | 86.3% | 1 | |
Yes | 41 (21.1%) | 95.1% | 2.5 (1.6, 3.8) | P<0.001 |
Lactate Dehydrogenase | ||||
Normal | 63 (32.5%) | 87.0% | 1 | |
Elevated | 131 (67.5%) | 90.5% | 2.3 (1.6, 3.2) | P<0.001 |
95%-CI = 95% confidence interval;
*21 patients had unknown values for LDH and were excluded; the model was adjusted for the confounding effects of the site of distant metastasis; no significant interaction was detected.
Due to the observed correlations, we additionally performed the survival analysis separately for 170 patients without brain involvement (
Univariate Analysis | Multivariate Analysis* | ||||||||
n | % | % dead | 1-year survival rate | [95%-CI#] (%) | p | Relative risk | [95%-CI#] | p | |
170 | 53.8 | 87.1 | 50.0 | [42.4; 57.6] | |||||
0.714 | |||||||||
Present | 67 | 39.4 | 91.0 | 52.2 | [40.2; 64.2] | ||||
Absent | 103 | 60.6 | 84.5 | 48.5 | [38.7; 58.3] | ||||
0.123 | |||||||||
Male | 92 | 54.1 | 90.2 | 45.3 | [35.1; 55.5] | ||||
Female | 78 | 45.9 | 83.3 | 55.6 | [44.4; 66.8] | ||||
0.878 | |||||||||
<50 years | 33 | 19.4 | 90.9 | 48.5 | [31.4; 65.6] | ||||
50–59 years | 32 | 18.8 | 84.4 | 52.1 | [34.5; 69.7] | ||||
60–69 years | 41 | 24.1 | 87.8 | 47.6 | [32.1; 63.1] | ||||
≥70 years | 64 | 37.6 | 85.9 | 51.2 | [38.9; 63.5] | ||||
0.962 | |||||||||
Dacarbazine | 132 | 77.6 | 85.6 | 49.4 | [40.8; 58.0] | ||||
Temozolomide | 38 | 22.4 | 92.1 | 51.9 | [35.8; 68.0] | ||||
<0.001 | |||||||||
Elevated | 49 | 32.0 | 89.8 | 29.3 | [16.4; 42.2] | 2.3 | [1.6; 3.4] | <0.001 | |
Normal | 104 | 68.0 | 84.6 | 56.2 | [46.6; 65.8] | 1.0 | |||
Missing | 17 | ||||||||
0.161 | |||||||||
Soft tissue | 28 | 16.5 | 82.1 | 59.5 | [41.1; 77.9] | ||||
Only lung | 59 | 34.7 | 96.6 | 49.2 | [36.5; 61.9] | ||||
Other visceral | 83 | 48.8 | 81.9 | 47.4 | [36.6; 58.2] |
# 95%-CI = 95% confidence interval; * 17 patients had unknown values for LDH and were excluded; the model was adjusted for the confounding effects of the site of distant metastasis; no significant interaction was detected.
Univariate Analysis | Multivariate Analysis |
||||||||
n | % | % dead | 1-year survival rate | [95%-CI |
p | Relative risk | [95%-CI |
p | |
45 | 100.0 | 95.6 | 18.7 | [7.1; 30.3] | |||||
0.575 | |||||||||
Present | 22 | 48.9 | 90.9 | 15.6 | [0.0; 31.5] | ||||
Absent | 23 | 51.1 | 100.0 | 21.7 | [4.8; 38.6] | ||||
0.344 | |||||||||
Male | 27 | 60.0 | 96.3 | 18.5 | [3.8; 33.2] | ||||
Female | 18 | 40.0 | 94.4 | 18.3 | [0.0; 36.7] | ||||
0.373 | |||||||||
<50 years | 14 | 31.1 | 92.9 | 17.8 | [0.0; 37.6] | ||||
50–59 years | 9 | 20.0 | 88.9 | 22.2 | [0.0; 49.4] | ||||
60–69 years | 11 | 24.4 | 100.0 | 36.4 | [8.0; 64.8] | ||||
≥70 years | 11 | 24.4 | 100.0 | 0.0 | na |
||||
0.618 | |||||||||
Dacarbazine | 11 | 24.4 | 100.0 | 9.1 | [0.0; 26.2] | ||||
Temozolomide | 34 | 75.6 | 94.1 | 21.8 | [7.7; 35.9] | ||||
0.007 | |||||||||
Elevated | 14 | 34.1 | 92.9 | 0.0 | na |
2.3 | [1.2; 4.9] | 0.014 | |
Normal | 27 | 65.9 | 96.3 | 22.2 | [6.5; 37.9] | 1.0 | |||
Missing | 4 |
95%-CI = 95% confidence interval;
na = not available.
*4 patients had unknown values for LDH and were excluded; no confounding effects were detected.
Within both groups LDH remained the only independent factor according to Cox regression analysis and the relative risk do die from disease was still 2.3-fold increased in case of elevated LDH (p = 0.014 and p<0.001 for patients with or without brain metastasis, respectively). The slight trend for a better survival of patients treated by dacarbazine compared to temozolomide, which was observed in the entire cohort (p = 0.146), was completely lost in these additional analyses performed separately for both groups of patients.
In the present study, we did not observe any difference in survival after start of first-line chemotherapy according to the
Conflicting results about prognostic impact of
Moreover, these
The only decisive factors for prognosis according to our analysis were LDH and the kind of visceral involvement. Cerebral involvement was more powerful than the visceral involvement according to AJCC to predict prognosis as described by others
In our study we found several correlations between analyzed factors which have to be discussed in more detail. The strong correlation between the treatment schedule and the
This unexpected correlation observed in the present study (grey broken arrow) can be explained as an indirect consequence of the appliance of institutional guidelines for treatment selection and established correlations (black arrows) between the rate of
The trend (p = 0.145) for a worse survival of patients treated with temozolomide is also explained by the appliance of these guidelines. In our cohort, 47.2% temozolomide treated patients but only 7.7% dacarbazine treated patients had cerebral involvement. If patients with brain metastases are excluded the difference in survival according to the used agent is no longer observed (p = 0.962). Moreover, no impact of the BRAF status on survival was found in patients with (p = 0.575) or without (p = 0.714) brain metastases if analyzed separately according to cerebral involvement.
In conclusion, survival of melanoma patients receiving first line treatment with either dacarbazine or temozolomide is associated with the serum LDH level and cerebral involvement but not dependent on the tumor