Table 1.
Clinical and histological features of 126 patients with colorectal cancer.
Fig 1.
Volume measurement using CT colonography.
a, b. Eccentric enhancing wall thickening (arrow) of the sigmoid colon is well demonstrated on axial CT images in prone position. Regions of interest (ROIs) (red line) are drawn covering abnormal wall thickening on every contiguous CT slices. Volume (cm3) is calculated by multiplying areas (cm2) and reconstruction interval (cm).
Table 2.
Mean and standard deviations of tumor volumes in each TNM stage.
Table 3.
Az value, optimal cut-off value, sensitivity, and specificity to differentiate TNM Staging.
Fig 2.
A 56-year old man with a T4b cancer at the descending colon.
(a) A huge low attenuating mass (arrows, red line) is well depicted on axial CT images in prone position. Tumor volume was 297.20 cm3. The mass closely abuts the small bowel loops (S) anteriorly. However, the radiologist considered this lesion as T4a stage with a confidence level of 2 (probably ≤ T4a). On operative field, tumor directly invaded into the ileum; therefore, en bloc resection including descending, sigmoid colons and attached ileum was performed. (b) A photograph of gross specimen after left hemicolectomy shows a bulky ulceroinfiltrative mass (*) at the colon with direct invasion to the adjacent ileum (arrowheads). Final histopathology confirmed a mucinous adenocarcinoma with pT4bN1bM0 stage (not shown).
Fig 3.
Receiver operating characteristic (ROC) curves of CT volumetry and conventional CT staging by radiologist to predict ≥ T2 (a), ≥ T3 (b), ≥ T4a (c), and T4b (d) stage of colorectal cancer. d. To predict T4b stage, the area under the ROC curve (Az, 0.780) of CT volumetry is significantly larger than that (0.591) of the radiologist (P = 0.004). For other T stages, Az values of CT volumetry and radiologist are not significantly different.
Fig 4.
Receiver operating characteristic (ROC) curves of CT volumetry and conventional CT staging by radiologist to predict ≥ N1 (a), ≥ M1 (b), and M1b (c) stage of colorectal cancer. a. To predict ≥ N1 stage, the area under the ROC curve (Az, 0.683) of the radiologist is significantly larger than that (0.532) of CT volumetry (P = 0.015). c. To predict M1b stage, Az value (0.857) of CT volumetry was greater than that (0.690) of the radiologist, albeit not significant (P = 0.238).
Table 4.
Comparative results of receiver operating characteristics analysis to determine TNM staging between CT volumetry and radiologist.
Fig 5.
Kaplan-Meier plots for the estimated proportional survival after colorectal cancer surgery according to the type of surgery (a), T (b), N (c), M (d) staging, and tumor volume (e) groups. Smaller tumor volume < 12.85 cm3 as well as lower T (≤ T3), N (N0) and M (M0) stage were significantly associated with good prognosis after CRC surgery (P<0.05). Vertical blips on curves = censored patients.
Table 5.
Results of Kaplan-Meier and log-rank analysis of factors associated with survival after colorectal cancer surgery.