Preoperative irradiation affects functional results after surgery for rectal cancer: results from a randomized study

The Swedish Rectal Cancer Trial has unequivocally demonstrated that preoperative high-dose (5 x 5 Gy) radiotherapy reduces local failure rates and improves overall survival. This will have an impact on the primary treatment of rectal cancer. This study investigates the effect of preoperative high-dose radiotherapy on long-term bowel function in patients treated with anterior resection.

A questionnaire was answered by 92 percent (203/220) of patients who were included in the Swedish Rectal Cancer Trial and who were alive after a minimum of five years. Thirty-two patients were excluded, mainly because of postoperative stomas and dementia, which left 171 for analysis.

Median bowel frequency per week was 20 in the irradiated group (n = 84) and 10 in the surgery-alone group (n = 87; P < 0.001). Incontinence for loose stools (P < 0.001), urgency (P < 0.001), and emptying difficulties (P < 0.05) were all more common after irradiation. Sensory functions such as "discrimination between gas and stool" and "ability to safely release flatus" did not, however, differ between groups. Thirty percent of the irradiated group stated that they had an impaired social life because of bowel dysfunction, compared with 10 percent of the surgery-alone group (P < 0.01).

The study indicates that high-dose radiotherapy influences long-term bowel function, thus emphasizing the need for finding predictive factors for local recurrence to exclude patients with a very high probability for cure with surgery alone and to use optimized radiation techniques.