Assessment of extent and completeness of mesorectal excision for rectal cancer by histopathology and MRI

Abstract

Introduction: High quality of total mesorectal excision (TME) surgical technique and critical feedback regarding its completeness by pathologist and a radiologist has been shown to influence the quality of surgery in patients with rectal cancer. In this study, we tried to audit the quality of TME by 2 independent observers, a consultant pathologist and radiologist. TME was performed for all patients with rectal tumors located <12 cm from the anal verge. Main Outcome Measures: TME specimens were examined for completeness by experienced single consultant pathologist to avoid interobserver bias. Postoperatively magnetic resonance imaging was done that was interpreted by a single consultant radiologist to avoid interobserver bias in the study. Discussion: Of total 103 patients, TME assessment was done in 53 patients. TME was complete in 35 cases (66%), near complete in 14 cases (26%), and incomplete in 4 cases (8%) (P<0.05). Twenty-eight cases were subjected to radiologic assessment of TME. Complete TME was found in 19 (67%) and residual mesorectum was found in 9 (32%). The radiologic findings co-related with pathology findings in these 28 cases as 17 cases were confirmed TME complete by both magnetic resonance imaging and histopathology, 4 cases were confirmed incomplete by both and out of 7 near complete TME by pathology, 2 were labeled as complete on radiology while 5 were labeled as incomplete (P<0.05). Seven (13.2%) cases had positive circumferential resection margin. Distal resection margin was >2 cm in about 81.1%, <2 cm in 15% and involved in 3.7% of cases. The lymph node yield was of 4–21 with an average of 11.5 nodes; with 54.7% having adequate nodal harvest (>12 lymph nodes). Conclusions: Pathologist’s and radiologist’s constructive criticism will always help a surgeon to improve his quality of TME.