EFFECT OF RADIOTHERAPY ON ANORECTAL FUNCTION IN PATIENTS WITH CERVICAL-CANCER

PURPOSE: The acute and long-term effects of pelvic radiation on defeca tion were studied. METHOD: Anorectal function was assessed based on ma nometry and subjective symptoms in 31 patients with. cervical cancer t reated by radiotherapy alone. Sixteen of 31 patients were examined per iodically before, during, and after radiotherapy (early group). Fiftee n others were examined more than six months after completion of radiot herapy (late group). RESULTS: One-third of patients in both groups had symptoms, mainly diarrhea and increased stool frequency. Patients in the late group also suffered from disturbed gas-stool discrimination, urgency, a sense of residual stool, and soiling. Anal canal resting pr essure was significantly higher after radiotherapy (47 +/- 15.5 mmHg) than before radiotherapy (36.3 +/- 12.5 mmHg; P < 0.05). The maximum t olerable volume decreased with radiation, from 163.3 +/- 45 before to 119.2 +/- 41.4 ml during, 112.7 +/- 36.6 ml immediately after, and 94. 6 +/- 34.4 ml in the late group (P < 0.01). Rectal compliance also dec reased over time and was lower in the early group (before, 5.7 +/- 1.3 ml/mmHg; P < 0.01; during, 4.6 +/- 2.2 ml/mmHg, P < 0.01; after, 3.7 +/- 1.4 ml/mmHg; P < 0.05) than the late group (2.1 +/- 1.5 ml/mmHg) a nd lower before than after in the early group (P < 0.01). Although rec tal pressure initiating continuous desire to defecate did not change, the maximum tolerable pressure was significantly higher in the late gr oup (81 +/- 19.5 mmHg) than during (59 +/- 16.8 mmHg) or after (59.9 /- 16.9 mmHg) radiotherapy in the early group (P < 0.05). CONCLUSION: Radiation reduces the capacity of the rectal reservoir, even in asympt omatic patients. These changes develop during radiotherapy and progres s over time.