Impact of specific modes of circumferential resection margin involvement in rectal cancer local recurrence: A retrospective study.

PURPOSE: To compare the local recurrence rate and overall survival between patients with circumferential resection margin (CRM) involvement by direct tumor spread and by a tumor within a lymph node. METHODS: A total of 776 patients diagnosed with rectal cancer underwent rectal resection. Patients with CRM involvement by direct tumor spread were named group A. CRM involvement by tumor within a lymph node formed group B. Patient data, including sex, age, pT, pN, stage I-III versus IV, neoadjuvant radiotherapy, adjuvant chemotherapy, carcinoembryonic antigen, primary tumor location, lymph node retrieval, and need for abdominoperineal resection, were compared between both groups. RESULTS: In total, 10.5% of the patients had CRM involvement. Of these, in 57 cases (7.3%), it was by direct tumor spread and in 19 cases (2.4%) by tumor within a lymph node. Other types of CRM involvement were found in six patients. With a mean follow-up of 32.9 months, 18 patients from group A (31.5%) and one patient from group B (5.2%) suffered a local recurrence. Local recurrence-free survival was significantly higher in patients from group B (P = 0.049). Patients in stage I-III (P = 0.037) and from group B ( P = 0.049) had better overall survival. CONCLUSION: Patients with CRM involvement by tumor within a lymph node have a low risk of local recurrence and better overall survival than patients with CRM involvement by direct tumor spread.