Circumferential resection margin as a prognostic marker in the modern multidisciplinary management of rectal cancer.

Abstract

A positive circumferential resection margin has been associated with a high risk of local recurrence and a decrease in survival in patients who have rectal cancer. The purpose of this study was to analyze the involvement of circumferential resection margin in local recurrence and survival in a multidisciplinary population-based setting by using tailored oncological therapy and surgery with total mesorectal excision. Data were collected in a prospective database and retrospectively analyzed. Between 1996 and 2009, 448 patients with rectal cancer underwent a curative bowel resection. Population-based data were collected at a single institution in the county of Västmanland, Sweden. Preoperative radiotherapy was delivered to 334 patients (74%); it was delivered to 35 patients (8%) concomitantly with preoperative chemotherapy. In 70 patients (16%), en bloc resections of the prostate and vagina were performed. Intraoperative perforations were seen in 7 patients (1.6%). The mesorectal fascia was assessed as complete in 117/118 cases. In 32 cases (7%), the circumferential resection margin was 1 mm or less. After a median follow-up of 68 months, 5 (1.1%) patients developed a local recurrence; one of them had circumferential resection margin involvement. The 5-year overall survival was 77%. In the multivariate analysis, the circumferential resection margin was not an independent factor for disease-free survival. Mesorectal fascia was not assessed before 2007. The findings might be explained by a type II error but, from a clinical perspective, enough patients were included to motivate the conclusion of the study. Circumferential resection margin is an important measurement in rectal cancer pathology, but the correlation to local recurrence is much less than previously stated, probably because of oncological treatment and surgery that respects the mesorectal fascia and, when required, en bloc resections. Circumferential resection margin should not be used as a prognostic marker in the modern multidisciplinary management of rectal cancer.