Quality of preoperative pelvic computed tomography (CT) and magnetic resonance imaging (MRI) for rectal cancer in a region in Ontario: A retrospective population-based study

Abstract

Background and objectives: Treatment decisions for rectal cancer rely on preoperative staging with CT and MRI scans. We assessed the quality of such scans in a region of Ontario.

Methods: We retrospectively collected data for patients undergoing rectal cancer surgery between July 2011 and December 2014. We measured three aspects of quality: use; comprehensiveness of reporting T-category, N-category, mesorectal fascia (MRF) status; and in non-radiated patients sensitivity and specificity of reports for relevant elements.

Results: A total of 559 patients underwent major rectal cancer surgery. Preoperative staging with CT and MRI was performed in 93% and 50% of patients. CT scan reports provided information on T-category, N-category, and MRF status in 41%, 92%, and 16% of cases. These same elements were reported on MRI in 88%, 93%, and 62% of cases. CT scan sensitivity and specificity was 80% and 80% for T-category, and 85% and 39% for N-category. MRI sensitivity and specificity was 75% and 81% for T-category, 79% and 37% for N-category, and 33% and 89% for MRF status.

Conclusion: In this region of Ontario, pre-operative MRI was underutilized, CT reporting of MRF status was low, and when reported sensitivity and specificity of T- and N-category were similar for CT and MRI.

Keywords: CT; MRI; rectal cancer; staging; surgery.