Rectal cancers with microscopic circumferential resection margin involvement (R1 resections): Survivals, patterns of recurrence, and prognostic factors.

Background and Objectives: We have reviewed our series of rectal cancer patients with circumferential resection margin involvement (R1) with particular regard to survival and prognostic factors. Methods: R1 rectal cancer patients undergoing surgery at the Leicester Royal Infirmary between 1998 and 2008. Age, gender, radiological, and pathological tumor characteristics, neoadjuvant and adjuvant therapies were examined as prognostic factors on the overall survival (OS) and disease-free survival (DFS) at 5-year follow-up. Results: A total of 885 rectal cancers were reviewed. Six hundred ninety-nine patients underwent a mesorectal excision and 71 of them were R1 resections (12.9%). OS was 43.7% (CI95% 33.5-53.8%; median survival 39 months). DFS was 57.4% (CI95% 43.0-71.8%; median survival 31 months). Pelvic recurrence rate occurred in 16 patients (26.2%, CI95% 16.5-36.0%), systemic recurrence rate in 23 patients (37.7%, CI95% 25.5-49.9%). At Cox-regression LNR and adjuvant chemotherapy were associated with both OS and DFS. No significant association was found between OS or DFS and adjuvant radiotherapy. Conclusions: In our series of R1 patients, the rates of local recurrence and OS at 5 years were 26.2% and 43.7%, respectively. Factors influencing systemic recurrences (LNR, adjuvant chemotherapy) are more associated with OS and DFS than those potentially affecting locoregional recurrences (adjuvant radiotherapy). (C) 2016 Wiley Periodicals, Inc.