Sphincter preservation following preoperative radiotherapy for rectal cancer: report of a randomised trial comparing short-term radiotherapy vs. conventionally fractionated radiochemotherapy.

BACKGROUND AND PURPOSE: The aim was to verify whether preoperative conventionally fractionated chemoradiation offers an advantage in sphincter preservation in comparison with preoperative short-term irradiation.

PATIENTS AND METHODS: Patients with resectable T3-4 rectal carcinoma without sphincters' infiltration and with a lesion accessible to digital rectal examination were randomised into: preoperative 5x5Gy short-term irradiation with subsequent total mesorectal excision (TME) performed within 7 days or chemoradiation to a total dose of 50.4Gy (1.8Gy per fraction) concomitantly with two courses of bolus 5-fluorouracil and leucovorin followed by TME after 4-6 weeks. Surgeons were obliged to base the type of operation on the tumour status at the time of surgery.

RESULTS: Between 1999 and 2002, 316 patients from 19 institutions were enrolled. The sphincter preservation rate was 61% in the 5x5Gy arm and 58% in the radiochemotherapy arm, P = 0.57. The tumour was on average 1.9 cm smaller (P < 0.001) among patients treated with chemoradiation compared with short-term schedule. For patients who underwent sphincter-preserving procedure, the surgeons generally followed the rule of tailoring the resection according to tumour downsizing; the median distal bowel margin was identical (2 cm) for both randomised groups. However, in the chemoradiation group, five patients underwent abdominoperineal resection despite clinical complete response.

CONCLUSIONS: Despite significant downsizing, chemoradiation did not result in increased sphincter preservation rate in comparison with short-term preoperative radiotherapy. The surgeons' decisions were subjective and based on pre-treatment tumour volume at least in clinical complete responders.