Accuracy of CT prediction of poor prognostic features in colonic cancer

Abstract

Whilst imaging of poor prognostic features in rectal cancers has assisted pre-operative treatment stratification, such features have yet to be evaluated in colonic cancers. This study aims to develop criteria for identifying poor prognostic features in colonic tumours and assess the accuracy of CT prediction against histopathology. Criteria were developed for predicting T-stage and N-stage, the presence of extramural vascular invasion and involvement of the retroperitoneal surgical margin (RSM). These criteria were tested on 33 patients with colonic cancer who underwent pre-operative high-resolution CT of their tumour. Two radiologists (Obs 1 and Obs 2) identified independently these poor prognostic features and the results were compared with the final histopathological results. Histological agreement and interobserver variation were calculated using the kappa test. Accuracy of CT prediction of tumour extension beyond muscularis propria was 82% (Obs 1) and 70% (Obs 2). Correct prediction of RSM involvement was 76% (95% confidence interval (CI): 57.8-88.9%) and 79% (95%CI: 61.1-91%) for Obs1 and Obs 2, respectively, with significant agreement between observers (kappa = 0.455, p = 0.050). Prognosis was correctly predicted using CT in 82% (95%CI: 61.5-81.2%) (Obs1) and 85% (95%CI: 68.1-94.9%) (Obs2) with moderate agreement (kappa = 0.459, kappa = 0.527, respectively) with histology. In conclusion, CT has potential as the imaging modality of choice in the pre-operative prediction of poor prognostic features in colonic cancers and could play a role in future treatment stratification.

The role of multidetector CT in local staging and evaluation of retroperitoneal surgical margin involvement in colon cancer

“…Our study has the largest series in which RSM was evaluated radiologically and compared pathologically, in the literature. Similar to Burton et al (11), DA was found to be 79% in the evaluation of RSM involvement. Agreement with pathology was not very good in both studies.…”

“…In T staging, the agreement between the observers was slight in our study (ĸ=0.351) and similarly it was slight (ĸ= 0.214) in a study performed by Burton et al (11). On the other hand, in Anderson et al (16), agreement between three observers was moderate to substantial (ĸ=0.523, 0.540, and 0.712) when staging was performed on axial images.…”

“…Thirty-three patients were included in that study and pathologically proven RSM involvement was reported in 3% of patients (11). The sensitivity and specificity of CT in the detection of RSM involvement in that study were 33% and 83% respectively.…”

“…Our findings are quite similar in the evaluation of EMI (sensitivity, 81% and 87%; specificity, 50% and 75%; DOR, 6.58 and 13.13). In a study of 33 patients Burton et al (11) reported 86% sensitivity, 75% specificity, and DOR=18 for the detection of EMI.…”

Local staging and assessment of colon cancer with 1.5-T magnetic resonance imaging

“…16 The accuracy of MRI in this study for the identification of EMVI was again good at 74% for Reader 1 and 69% for Reader 2. The accuracy of CT for the identification of EMVI is reported in three previous studies; Burton et al reported an accuracy of 55% for Observer 1 and 61% for Reader 2, 31 Dighe et al 32 reported an accuracy of 70% and Rollven et al reported an accuracy of 78% for Reader 1 and 69% for Reader 2. Rollven et al also reported the accuracy of MRI of 78% and 82%.…”