Abstract:

Objective To explore the higher risk factors for positive circumferential resection margin (CRM) in rectal cancer. Methods The patients with rectal cancer undergoing surgery in Fudan University Shanghai Cancer Center between January 2006 to April 2018 were collected, and 71 patients with positive CRM were included in positive group in this study. One hundred forty-two patients with negative CRM as negative group were matched by random number method with a ratio of 2∶1. Clinicopathologic analysis was done for positive group compared with negative group. Uni and multifactorial analysis assessed the risk factors for positive CRM. Results It was shown by univariate analysis of two groups that significantly different factors were distance of tumor to the anal verge (P<0.001), surgery type (P<0.001), differentiation extent (P<0.001), lymphovascular invasion P=0.001), perineural invasion (P<0.001), T stage (P<0.001), N stage (P=0.001), TNM stage (P<0.001), and neoadjuvant chemoradiotherapy (P=0.049). Patients in CRM positive group had higher locoregional recurrence rate(P=0.001), higher distant metastases rate (P<0.001) and less overall survival (P<0.001) compared with those in negative group. Multifactorial analysis demonstrated that poor differentiation (OR=4.415; 95% CI: 1.906-10.224; P=0.001), perineural invasion (OR=3.344; 95% CI: 1.431-7.817; P=0.005) and T₃-T₄ in pathological stage (OR=3.225; 95% CI: 1.026-10.142; P=0.045) were independent higher risk factors for positive CRM. Conclusions Positive CRM predicted a worse clinical outcome. Poor differentiation, perineural invasion and T₃-T₄ of pathological stage were higher risk factors for positive CRM in rectal cancer patients after curative surgery.

Key words: Rectal cancer, Circumferential resection margin, Higher risk factor