Continuous Effect of Radial Resection Margin on Recurrence and Survival in Rectal Cancer Patients Who Receive Preoperative Chemoradiation and Curative Surgery: A Multicenter Retrospective Analysis

Abstract

To elucidate the proper length and prognostic value of resection margins in rectal cancer patients who received preoperative chemoradiotherapy (CRT) followed by curative total mesorectal excision (TME). A total of 1476 rectal cancer patients staging cT3-4N0-2M0 were analyzed. All patients received radiation dose of 50.4Gy in 28 fractions with concurrent 5-fluorouracil or capecitabine. Total mesorectal excision was performed 4 to 8weeks after radiation therapy. The recurrence-free survival (RFS) at 5years showed a significant difference between 3 groups: patients with circumferential resection margin (CRM) ≤1mm, CRM 1.1 to 5mm, and CRM >5mm (46.2% vs 68.6% vs 77.5%, P<.001). Patients with CRM ≤1mm showed a significantly higher cumulative incidence of locoregional recurrence (P<.001) and distant metastasis (P<.001) at 5years compared with the other 2 groups. Patients with CRM 1.1 to 5mm showed a significantly higher cumulative incidence of distant metastasis (P<.001), but not locoregional recurrence (P=.192), compared with those with CRM >5mm. Distal resection margin (≤5 vs>5mm) did not show any significant difference in cumulative incidence of locoregional recurrence (P=.310) and distant metastasis (P=.926). Rectal cancer patients with CRM ≤1mm are a high-risk group, with the lowest RFS. Patients with CRM 1.1 to 5mm may be at intermediate risk, with moderately increased distant recurrence. Distal resection margin was not significantly associated with RFS in rectal cancer after neoadjuvant CRT and total mesorectal excision.