HIGH-DOSE PREOPERATIVE EXTERNAL-BEAM AND INTRAOPERATIVE IRRADIATION FOR LOCALLY ADVANCED PANCREATIC-CANCER

Purpose: To analyze results of high-dose preoperative external beam irradiation followed by surgical exploration and intraoperative radiation therapy in patients with unresectable pancreatic cancer. Methods and Materials: From December 1983 through December 1990, 27 patients with primary unresectable but localized pancreatic adenocarcinoma received high-dose (50 to 54 Gy) external beam irradiation with or without concomitant bolus 5-fluorouracil followed by surgical exploration and intraoperative electron beam irradiation (20 Gy) at the Mayo Clinic. Results: Local control was achieved in 21 of 27 (78%) patients. Actuarial local control at 1, 2, and 5 years was 86%, 68%, and 45%, respectively. In 19 (70%) of the 27 patients, distant metastasis developed, and peritoneal or liver progression (or both) was found in 14 (52%). The actuarial distant metastasis rate at 2 and 5 years was 69% and 83%, respectively. Median survival from the date of diagnosis was 14.9 months. Actuarial 2- and 5-year overall survival was 27% and 7%, respectively. These survival rates are higher (p = 0.001) than the 6% and 0% actuarial 2- and 5-year survival observed in 56 patients who underwent intraoperative radiation therapy followed by post-operative high-dose external beam treatment at our institution. Conclusion: Administering the full component of external beam irradiation before exploration and intraoperative radiation therapy may be more appropriate because it allows better patient selection. Unfortunately, altered patient selection was not effective in decreasing the relative risk of abdominal failure. Because effective systemic chemotherapy does not currently exist, whole abdominal irradiation alone or in combination with chemotherapy warrants evaluation.