Results of external beam radiotherapy alone for incompletely resected carcinoma of rectosigmoid or rectum: Peter MacCallum Cancer Institute experience 1981-1990

Purpose: To study the results of external beam radiotherapy treatment for i ncompletely resected nonmetastatic rectosigmoid and rectal carcinoma. Methods and Materials: A retrospective review was carried out of all patien ts (57)presenting to Peter MacCallum Cancer Institute from 1981 to 1990 wit h incompletely resected nonmetastatic rectosigmoid or rectal cancer who wer e treated with external beam radiotherapy. Three radiotherapy schedules wer e used: radical (50 to 60 Gy, 27 patients), high-dose palliative (45 Gy, 25 patients), and low-dose palliative (less than 45 Gy, 5 patients). Symptoma tic response, overall survival, and the effect of prognostic factors on tre atment outcome were evaluated. The median follow-up period for survivors wa s 49 months. Results: Symptomatic response rates were 83% and 79% for the radical and hi gh-dose palliative groups respectively. The estimated median survival time from presentation for all patients was 16.4 months (radical 26.1 months, hi gh-dose palliative 15.7 months). Patients with microscopic residual disease survived significantly longer than patients with macroscopic residual dise ase (estimated median survival time 30.7 months vs. 14.3 months,p = 0.013). Conclusions: No dose response effect was seen between the radical group and high-dose palliative group. Microscopic residual disease at presentation w as the only significant predictor of better survival. The conventionally fr actionated course of 50 to 60 Gy was not significantly better in terms of p alliation and overall survival than a shorter palliative course of 45 Gy. I n future, preoperative chemoradiation should improve outcome by reducing th e number of patients with incompletely resected cancer. (C) 1999 Elsevier S cience Inc.