Treatment of rectal adenocarcinoma with endocavitary and external beam radiotherapy: Results for 199 patients with localized tumors

Purpose: Endocavitary radiation (RT) provides a conservative alternative to proctectomy. Although most suitable for small, mobile lesions, patients wi th less favorable tumors are often referred if they are poor surgical candi dates. Knowing the extent to which radiation can control such tumors can be an important factor in making clinical decisions. Methods and Materials: One hundred ninety-nine patients, who received endoc avitary RT with or without external beam RT (EBRT) during 1981 through 1995 , were followed for disease status for a median of 70 months, including dea ths from intercurrent causes. In the early years of the study, 21 patients were treated with endocavitary RT alone, the remainder of the patients rece ived pelvic EBRT (usually 45 Gy in 25 fractions) 5-7 weeks before endocavit ary RT. Results: Overall, 141 patients (71%) had local control with RT alone. Salva ge surgery rendered an additional 20 patients disease free, for an ultimate local control rate of 81%. On multivariate analysis for local control (exc luding surgical salvage), the most significant factors were mobility to pal pation, use of EBRT, and whether pretreatment debulking of all macroscopic disease had been done (generally a piecemeal, nontransmural procedure). Of 77 cases staged by transrectal ultrasonography, the local control rate with RT alone was 100% for uT1 lesions, 85% (90% with no evidence of disease af ter salvage) for freely mobile uT2 lesions, and 56% (67% with no evidence o f disease after salvage) for uT3 lesions and uT2 lesions that were not free ly mobile. Conclusions: Patients with small mobile tumors that are either uT1 or have only a sear after debulking achieve control with endocavitary RT. About 15% of mobile uT2 tumors fail RT; therefore, careful excellent local control w ith endocavity RT. About 15% of mobile uT2 tumors fail RT; therefore, caref ul follow-up is critical. Small uT3 tumors are appropriate for this treatme nt only if substantial contraindications to proctectomy are present. (C) 20 01 Elsevier Science Inc.