Prognostic implications of circumferential location of distal rectal cancer

This study evaluated the prognostic importance of circumferential tumour position of mid and low rectal cancers.

All uT2, uT3 and uT4 tumours of the middle and lower rectum that underwent total mesorectal excision (TME) with curative intent between 1996 and 2006 were included. The predominant circumferential tumour position (anterior, posterior or circumferential) was defined on preoperative endorectal ultrasound examination (ERUS). The relationships between tumour position and other characteristics and recurrence were explored.

Two hundred and five patients with distal rectal cancer were operated on for a uT2-T4 tumour. Median follow up was 49 months. The location of the tumour was predominantly anterior, posterior or circumferential in 128, 49 and 27 patients, respectively. Anterior tumours were more likely to receive neoadjuvant therapy (P = 0.016) and perioperative blood transfusion (P = 0.012). No significant differences were observed between circumferential position and pT or pN stage, circumferential resection margin involvement or mesorectal excision quality. Sixty-three (30.7%) patients developed recurrence, which was local only in 16 (7.8%). Although tumours involving 360° of the rectal wall had a higher risk of local recurrence (P = 0.048), those with a predominant anterior or posterior position were not related to a higher risk of local or overall recurrence.

Anterior rectal tumours do not differ in pathological characteristics from posterior tumours, and their prognosis is no worse when circumferential resection is complete.