Local excision and post-operative radiation therapy for rectal carcinoma.

PURPOSE: To assess the patterns of failure and outcome following conservative surgery and post-operative radiation therapy for rectal cancer.

METHODS AND MATERIALS: Twenty-five patients underwent post-operative radiation therapy (50 Gy in 20 fractions over 4 weeks) following local excision or electrocoagulation for carcinoma of the rectum. None of the patients had palpable residual disease following surgery. Selection factors for post-operative radiation therapy were refusal of a permanent colostomy, excessive operative risk of an abdominal perineal resection and concern regarding local control with conservative surgery alone.

RESULTS: Six of 25 patients developed failure at the primary site. There was no lymph node failure. All five patients with primary failure alone underwent abdominal perineal resection and 2 remained free of recurrence. With a median follow-up of 6 years, 20 of 25 patients remained alive and free of disease. There was no apparent influence of age, sex, type of surgery, tumor size, distance of tumor from anal verge, tumor configuration, resection margins, integrity of the resected tissue, depth of invasion, differentiation, presence of lymphatic or vascular channel invasion, radiation dose or field size on local control and survival. One of 15 patients failed locally when the overall treatment time was 30 days or less, whereas 5 of 10 patients developed local failure when the overall treatment time exceeded 30 days. Sixteen of 20 patients in whom cancer did not recur retained normal anorectal function. All four patients with grade 3 early morbidity and the only patient with Grade 3 late morbidity were amongst the group of 13 patients treated with large AP-PA fields (mean: 15 x 19 cm2).

CONCLUSION: In selected patients who are at high risk of local recurrence following local excision alone, and who refuse a colostomy or are at high operative risk from radical surgery, post-operative radiation therapy is an alternative to radical surgery.