Long-term results of Intraoperative electron beam irradiation (IOERT) for patients with unresectable pancreatic cancer

Background Data: To analyze the effects of a treatment program of intraoperative electron beam radiation therapy (IOERT) and external beam radiation therapy and chemotherapy on the outcome of patients with unresectable or locally advanced pancreatic cancer. Methods: From 1978 to 2001, 150 patients with unresectable and nonmetastatic pancreatic cancer received IOERT combined with external beam radiation therapy and 5-fluorouracil-based chemotherapy for definitive treatment. Results: The 1-, 2-, and 3-year actuarial survival rates of all 150 patients were 54%, 15%, and 7%, respectively. Median and mean survival rates were 13 and 17 months, respectively. Long-term survival has been observed in 8 patients. Five patients have survived beyond 5 years and 3 more between 3 and 4 years. There was a statistically significant correlation of survival to the diameter of treatment applicator (a surrogate for tumor size) used during IOERT. For 26 patients treated with a small-diameter applicator (5 cm or 6 cm), the 2- and 3-year actuarial survival rates were 27% and 17%, respectively. In contrast, none of the I I patients treated with a 9-cm-diameter applicator survived beyond IS months. Intermediate survival rates were seen for patients treated with a 7- or 8-cm-diameter applicator. Operative mortality was 0.6%. and postoperative and late complications were 20% and 15%, respectively. Conclusions: A treatment, strategy employing IOERT has resulted in long-term survival in 8 of 150 patients with unresectable pancreatic cancer. Survival benefit was limited to patients with small tumors. Enrollment of selected patients with small tumors into innovative protocols employing this treatment approach is appropriate.