Importance:
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.
Objective:
To evaluate the prognostic importance of CT imaging features of sigmoid colon cancer.
Design:
Retrospective database analysis performed April 2019.
Setting
Tertiary centre receiving international and national referrals for colorectal cancer.
Participants:
Patients undergoing bowel resection for sigmoid colon cancer between 2006 and 2015.
Main Outcome and Measures:
Cox regression analysis was performed to investigate CT risk factors associated with recurrence. Kaplan Meier survival plots were calculated for disease free survival (DFS) using CT staging systems.
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.
Conclusions and Relevance:
T3 substaging and detection of TDs or EMVI on CT were prognostic factors 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.