Comparison of Risk Factors for Locally Advanced Lower Rectal Cancer Recurrence Evaluated by Magnetic Resonance Imaging and Pathological Factors Analysed by Longitudinal Slicing Method.

Background/aim We compared the risk factors for locally advanced lower rectal cancer (LALRC) recurrence evaluated by preoperative magnetic resonance imaging (MRI) and pathological factors analysed via the longitudinal slicing method to identify high risk groups for recurrence. Patients and methods This retrospective single-institution cohort study analysed 45 consecutive patients who underwent curative surgery for LALRC. Data were analysed by an experienced radiologist and pathologist. Results Final preoperative extramural venous invasion (EMVI) and extramural depth of invasion (EMD) determined via MRI were significantly associated with EMVI and EMD determined via pathological analysis. The log-rank test for disease-free survival based on initial preoperative factors showed significantly poor prognoses for circumferential resection margin (CRM)-positive, EMVI-positive, and EMD-positive patients. Conclusion Final preoperative EMVI and EMD determined via MRI correlated with pathological EMVI and EMD, especially in patients who did not undergo preoperative treatment. CRM, EMVI, and EMD determined via preoperative MRI were significant risk factors for recurrence.