Computerized Tomography Criteria as a Tool for Simplifying the Assessment of Locally Advanced Rectal Cancer

Abstract

Rectal cancer represents a leading cause of mortality worldwide. Staging defines the local and distant extent of the disease, guides management, and predicts prognosis. Different modalities are available for staging including TRUS (transrectal ultrasound), CT (computed tomography), and MRI (magnetic resonance imaging). The objective of this study was to screen and isolate CT imaging parameters suggestive of advanced rectal cancer and its utility as a tool in simplifying the staging protocol making further imaging studies unnecessary. Retrospective, single center study. Seventy-five patients with rectal carcinoma were included and were divided into two groups according to their T score and nodal involvement status, as diagnosed by TRUS. Group 1 (n = 15) "local disease" (T1/T2 N0) and group 2 (n = 60) "locally advanced disease" are both eligible for neoadjuvant treatment (N/any T or T3/any N). For each patient, three CT imaging parameters that represent locally advanced disease, i.e., perirectal fat infiltration, local lymphadenopathy, and rectal wall thickening, were evaluated and compared between the two groups. The capability of CT imaging to accurately predict locally advanced rectal carcinoma. Rectal wall thickening on CT was found to have 92% PPV and perirectal lymphadenopathy 96% PPV for predicting a locally advanced stage. A combination of those two parameters results in a predictive PPV of 98%. This was a single center retrospective study, with a relatively small cohort. CT is a valuable tool in the assessment and management of rectal carcinoma as it can identify locally advanced rectal cancer. This enables treatment without any further unnecessary evaluation.