Intraoperative and external beam irradiation with or without resection: Mayo pilot experience.

At our institution, intraoperative radiation therapy (IORT) with an electron beam has been administered as a single boost dose of 1,000 to 2,000 cGy (rad) in combination with 4,500 to 5,000 cGy (rad) of fractionated external beam irradiation. From April 1981 to July 1983, 50 patients received such treatment, and results are analyzed in detail in this article. All patients had locally advanced disease (initially unresectable for cure, residual after resection, or recurrent), and the main disease sites were gastrointestinal (pancreatic, colorectal, and biliary tumors) and soft tissue (sarcomas). Disease-free survival to date has been excellent in our colorectal and biliary subsets of patients. Although local progression has not been a major problem in patients with unresectable pancreatic lesions, failures in the liver and peritoneal cavity have been excessive, and treatment strategies have been altered in an attempt to decrease the frequency of such failures. Although both short-term and long-term morbidity are acceptable, pilot trials with use of radiation-dose modifiers are planned to determine whether the therapeutic ratio of local control to associated complications can be improved even further.