Perineal effects of postoperative treatment for adenocarcinoma of the rectum.
Nine (4%) first recurrences that involved the perineum were identified in a randomized study of 202 patients treated by no further therapy, chemotherapy only, radiotherapy only, combined radiotherapy and chemotherapy, following complete surgical excision of adenocarcinoma of the rectum. Six of these were in unirradiated patients and in two of the three irradiated patients the perineum was included in the treatment volume. Eight of the nine patients were male and all nine had received abdominoperineal resection (APR). Our quality assurance procedures identified 22 of 96 irradiated patients in whom the perineum was grossly outside the fields. Sixteen of these had undergone APR. As only one of these 16 relapsed in the perineum no definite effect of the surgical procedure on the likelihood of perineal recurrence could be demonstrated. Examination of the pathology reports revealed that 28 patients undergoing APR had tumors within 2 cm of the anorectal junction (pectinate line). Five (17.8%) developed perineal recurrence compared with 4 (3.6%) of 110 patients whose tumors were more than 2 cm from the anus (p less than 0.02-Fisher exact test). No survival differences could be demonstrated between those receiving perineal irradiation and those not but perineal irradiation was associated with toxicity with at least nine (12.2%) out of 74 developing severe complications directly related to the perineum. The routine inclusion of the perineum in postoperative pelvic irradiation fields for all cases of adenocarcinoma of the rectum is questioned. Our current policy following APR includes optional coverage of the perineum for those tumors more than 5 cm from the anorectal junction.