Poster Abstracts

Abstract

Purpose: Pre-operative TNM stratification of colon cancer on computed tomography (CT) at present does not identify patients at high risk of recurrence that could be selected for pre-operative treatment. In this study, we aimed to identify an optimal method of predicting colon cancer recurrence by pre-operative CT staging. Methods: Preoperative CT scans of 414 patients with sigmoid colon cancer between were re-staged using 3 CT classification systems for poor prognosis disease. "CT-TNM": T3-4 tumours; "CT-T3 substage": T3 tumours with extramural depth over 5 mm and T4 tumours. "CT-TDV": tumours with extramural venous invasion (EMVI) or discontinuous tumour deposits. Kaplan Meier survival plots and Cox multi-regression analysis were performed. Results: Among the 414 patients included with sigmoid cancer with a median follow up of 61 months, 122 patients developed recurrence (29.5%). On multivariate analysis, nodal disease was not prognostic and only TDs (HR 1.90) and EMVI (HR 1.97) on CT were associated with recurrence. Significant differences in DFS were found by CT-T3 substage classification (HR 1.88, 95% CI(1.32-2.68)) but not CT-TNM (HR 1.55, 95% CI(0.94-255)). The presence of EMVI or TDs on CT (HR 2.45, 95% CI(1.68-3.56)) best identified poor outcome. Conclusion: T3 substage and detection of TDs or EMVI on CT were prognostic for DFS, whereas TNM and nodal staging on CT held no prognostic value. TDV staging of sigmoid colon cancer is superior to TNM on CT and could be used to pre-operatively identify patients at high risk of recurrence. 6 Meta-analysis of oncological outcomes of sigmoid cancers: a hidden epidemic of R1 "palliative" resections