The influence of circumferential resection margins on survival following rectal cancer surgery.

Background And Aims: A negative (R0) circumferential resection margin (CRM) is described as one of the most important factor that decrease the rate of local recurrence in rectal cancer. The primary outcome of the study was the status of the CRM, while the secondary outcomes were local recurrence and overall survival.

Methods: Study includes 192 patients with rectal cancer operated between January 2012 and December 2013 in our Institute. The incidence of positive CRM and its impact on the survival rates after oncologic surgical resection were investigated along with factors that determine positive CRM. R1 was defined as a distance of ≤ 1 mm between the tumor and the resection margin.

Results: The R1 rate was 3.6 % (7 cases). Nine patients (4.68%) developed local recurrence during a median followup period of 720 days. A positive CRM was found to be a risk factor of local recurrence (p-value = 0.031) and it decreased the overall survival (p-value=0.001). pT4 stage (p-value=0.008) and vascular invasion (p-value=0.005) are factors that play significant roles in determining CRM positivity. In case of inferior rectal tumours abdomino-perineal resection (APR) determines significantly higher (p-value=0.048) rates of positive CRM than anterior resection (AR) of the rectum.

Conclusions: Positive CRM affects overall survival and local recurrence in rectal cancer. pT4 stage and vascular invasion play determinant roles in determine CRM status. APR is a risk factor for positive CRM in inferior rectal tumors.

Key Words: Abdomino-perineal resection, Circumferential resection margins, Local recurrence, Rectal cancer, Overall survival.