LOW RECTAL-CANCER - IMPACT OF RADIATION AND CHEMOTHERAPY ON SURGICAL-TREATMENT

INTRODUCTION: The aim of this study was to evaluate the impact of comb ined radiotherapy and chemotherapy (leucovorin and 5-fluorouracil) on the treatment of potentially resectable low rectal cancer using the fo llowing end points: 1) toxicity of this combined modality regimen; 2) clinical and pathologic response rate and local control; 3) down-stagi ng of the tumor and its influence on the number of sphincter-saving op erations; 4) disease-free interval, patterns of relapse, and overall s urvival. METHODS: From 1991 to 1996, 118 patients with potentially res ectable cases of histologically proven adenocarcinoma and no distant m etastases were enrolled into this protocol. All patients were evaluate d by clinical and proctologic examination, abdominal computed tomograp hy, transrectal ultrasound, and chest radiography. Therapy consisted o f 5,040 cGy (6 weeks) and concurrent leucovorin (20/mg/m(2)/day) with bolus doses of 5-fluorouracil administered intravenously at 425 mg/m(2 )/day for three consecutive days on the first and last three days of r adiation therapy. After two months, all patients underwent repeat eval uation and biopsy of any suspected residual lesions or scar tissue. RE SULTS: Median follow-up was 36 months. Toxicity of chemotherapy regime n was minimum. Thirty-six patients (30.5 percent) were classified as b eing complete responders. In six of these patients, complete response was confirmed by the absence of tumor in the surgical specimens (3 abd ominoperineal resections and 3 proctosigmoidectomies with coloanal ana stomosis). In the remaining 30 patients, confirmation of a complete re sponse was made by the absence of symptoms, negative findings on physi cal examination, and biopsy, transrectal ultrasound, and pelvic comput ed tomographic test results during follow-up. Eighty-two patients (69. 4 percent) were considered incomplete responders. Residual lesions had already been identified during the first examination in 74 patients. In the other eight patients, residual tumor was only identified after 3 to 14 months. All patients underwent surgical treatment, except one patient who refused surgery. Eighty-seven patients underwent 90 surgic al procedures: local excision, 9; coloanal anastomosis, 36; abdominope rineal resection, 4; Hartmann's procedure, 1. Isolated local recurrenc es occurred in five patients (4.3 percent) and combined local and dist ant failure in eight patients (6.7 percent). Ninety patients are alive and disease-free at a median follow-up of 36 months. CONCLUSIONS: Com bined up-front chemoradiotherapy was associated with tolerable and acc eptable side effects. A significant number of patients had complete di sappearance of their tumors (30.5 percent) within a median follow-up o f 36 months. This regimen spared 26.2 percent of patients from surgica l treatment and allowed sphincter-saving management in 38.1 percent of patients who may have required abdominoperineal resection. Preliminar y results of this trial suggests a seduction in the number of local re currences and reinforces the concept that infiltrative low rectal canc er may be initially treated by chemoradiotherapy.