THE IMPACT OF 5-FLUOROURACIL AND INTRAOPERATIVE ELECTRON-BEAM RADIATION-THERAPY ON THE OUTCOME OF PATIENTS WITH LOCALLY ADVANCED PRIMARY RECTAL AND RECTOSIGMOID CANCER

Objective To analyze the effects of 5-fluorouracil (5-FU) chemotherapy combined with preoperative irradiation and the role of intraoperative electron beam irradiation (IOERT) on the outcome of patients with pri mary locally advanced rectal or rectosigmoid cancer. Methods From 1978 to 1996, 145 patients with locally advanced rectal cancer underwent m oderate- to high-dose preoperative irradiation followed by surgical re section. Ninety-three patients received 5-FU as a bolus for 3 days dur ing the first and last weeks of radiation therapy (84 patients) or as a continuous infusion throughout irradiation (9 patients). At surgery, IOERT was administered to the surgical bed of 73 patients with persis tent tumor adherence or residual disease in the pelvis. Results No dif ferences in sphincter preservation, pathologic downstaging, or resecta bility rates were observed by 5-FU use. However, there were statistica lly significant improvements in 5-year actuarial local control and dis ease-specific survival in patients receiving 5-FU during irradiation c ompared with patients undergoing irradiation without 5-FU. For the 73 patients selected to receive IOERT, local control and disease-specific survival correlated with resection extent. For the 45 patients underg oing complete resection and IOERT, the 5-year actuarial local control and disease-specific survival were 89% and 63%, respectively. These fi gures were 65% and 32%, respectively, for the 28 patients undergoing I OERT for residual disease. The overall 5-year actuarial complication r ate was 11%. Conclusions Treatment strategies using 5-FU during irradi ation and IOERT for patients with locally advanced rectal cancer are b eneficial and well tolerated.