Distal margins in radical resections for rectal cancer after chemoradiation therapy: how short is long enough?

The purpose of our study was to assess the impact of distal margin length on outcome in patients with rectal cancer treated with neoadjuvant chemoradiation therapy (CRT) followed by radical resection.

Fifty-three consecutive patients were evaluated. The selection criteria included: adenocarcinoma of the mid- or distal rectum, locally advanced stage, absence of distant metastases, and preoperative CRT followed by proctectomy with total mesorectal excision. The operations included low anterior resection in 33 patients (62%) and abdominoperineal resection in 20 (38%). The outcome measures were: tumor regression, complete pathologic response, length of distal resection margins, status of radial margins and recurrence rate.

Forty-eight patients (91%) had tumor regression, and 11 (21%) had a complete pathologic response. Distal resection margins were tumor-free in all patients, ranging in length from 0.1 to 7.4 cm (mean = 2.2). Follow-up (mean = 48.8 months) was current in 50 of 53 patients (94%). There was no locoregional recurrence.

Distal resection margins shorter than 1-2 cm appear to be equivalent to longer margins in patients who undergo CRT followed by proctectomy with total mesorectal excision. These findings may lead to greater utilization of sphincter-saving procedures in rectal cancer.