Prognostic significance of circumferential resection margin following total mesorectal excision and adjuvant chemoradiotherapy in patients with rectal cancer

Background: This study was designed to evaluate the prognostic value of circumferential resection margin (CRM) in rectal cancer patients who underwent curative resection with adjuvant chemoradiotherapy (CRT). Methods: We studied 504 patients who underwent total mesorectal excision with adjuvant CRT for rectal cancer between 1997 and 2001. The patients were divided into two groups: a negative CRM group (CRM > 1 mm) and a positive CRM group (CRM <= 1 mm). The survival rates, local recurrence rates, and systemic recurrence rates were compared between groups. Results: The negative CRM group had 460 patients and the positive CRM group had 44 patients. The 5-year local and systemic recurrence rates were 11.3 and 25.3%, respectively, in the negative CRM group and 35.2 and 60.8% in the positive CRM group, respectively. The cancer-specific 5-year survival rates for the two groups were 72.5 and 26.9% (P < .001), respectively. CRM was found to be an independent prognostic factor by multivariate analyses which were adjusted for known outcome predictors (P < .001). Conclusion: Oncological outcome for patients in the positive CRM group is less favorable than for those in the negative CRM group. Adjuvant CRT is not a definite treatment modality that can be used to compensate for a positive CRM following TME and adjuvant CRT in patients with TNM stage II or III rectal cancer.