Local excision and postoperative radiation therapy for rectal adenocarcinoma.

Abstract

Sixty-seven patients with early-stage adenocarcinoma of the rectum who had lesions thought to be unsuitable for either local excision alone or endocavitary irradiation were treated with local excision followed by postoperative radiation therapy. The purpose of this study was to evaluate the effectiveness of local excision followed by radiation therapy for treatment of rectal adenocarcinoma. The patients were treated between 1974 and 1999; follow-up time was 6 to 273 months (median, 65 months). All living patients had follow-up for at least 2 years. The indications for postoperative irradiation included equivocal or positive margins, invasion of the muscularis propria, endothelial-lined space invasion, poorly differentiated histology, and perineural invasion. Cox proportional hazards regression analysis was performed using six explanatory variables including tumor size, configuration (exophytic vs. ulcerative), histologic differentiation, pathologic T stage, endothelial-lined space invasion, and margin status. The time interval between treatment and development of recurrent disease was in the range of 11 to 48 months. The 5-year results were as follows: local-regional control, 86%; ultimate local-regional control, 93%; distant metastasis-free survival, 93%; absolute survival, 80%; and cause-specific survival, 90%. When the Cox proportional hazards regression analysis was performed for these endpoints, margin status influenced absolute survival (P = 0.0074), cause-specific survival (P = 0.0405), and ultimate local-regional control (P = 0.0439). Tumor configuration marginally influenced cause-specific survival (P = 0.0577). None of the variables had an influence on the endpoints' local-regional control, ultimate local-regional control with sphincter preservation, or distant metastasis. Five patients (7%) had severe complications; no complication was fatal. Local excision and postoperative radiation therapy results in a high probability of local-regional control and survival for selected patients with relatively early-stage rectal adenocarcinoma. Patients with ulcerative tumors may have a lower likelihood of cause-specific survival.