The future of external beam irradiation as initial treatment of rectal cancer.

Several trials have demonstrated that pre-operative irradiation for rectal cancer decreases significantly the incidence of pelvic recurrence. However, this method is far from being generally accepted. It is now possible to enhance the effectiveness of external beam irradiation and to use it to extend the field of sphincter-saving and conservative procedures. Our protocol consists of a split-course regimen with a short course of cobalt-60 arc rotation (3000 cGy in 12 days). After 2 months rest, the second stage of treatment depends upon the pressure of residual disease and the site of the tumour. It consists of either radical surgery (82 cases) or conservative treatment by intracavitary irradiation in the event of a favourable initial response or in the case of poor risk patients (73 cases). In the radiotherapy-surgical group, the subsequent operative specimens were tumour free in 17 per cent of cases and assigned to Dukes' A category in 32 per cent of cases. Of 91 patients with T2 or T3 tumour involving the lower third of the rectum (followed up for more than 3 years) 72 (84 per cent) had no recurrence. Thirty-three of these patients (46 per cent) underwent a colostomy while 39 (54 per cent) had normal anal function. These results demonstrate the major place that a properly planned external beam irradiation can have in the curative management of cancers of the low rectum.