Prognostic implication of intraoperative radiotherapy for unresectable pancreatic cancer.
346 Background: There is no established treatment strategy for unresectable pancreatic cancer, and the prognostic effect of intraoperative radiotherapy (IORT) is considered to be limited. Methods: We reviewed 614 surgical cases of pancreatic cancer and selected 198 cases that did not undergo pancreatectomy because of distant metastasis or locally advanced disease, at the Department of Surgery II, between July 1981 and June 2009. Liver metastasis was observed in 70 patients and peritoneal metastasis in 44. Treatment for those who were feasible consisted of IORT and/or postoperative chemotherapy. Overall survival and prognostic factors were evaluated for all patients and for each pattern of disease spread. Results: IORT was performed in 120 patients (61%), and chemotherapy was indicated in 80 (40%). Overall survival in the non-treatment group was significantly inferior to that for IORT alone and IORT plus gemcitabine (GEM)-based chemotherapy (median survival time: 3.2 months vs. 6.1 and 7.9 months; P = 0.0001 and <0.0001, respectively). After multivariate analysis, IORT and GEM-based chemotherapy were identified as independent prognostic factors [hazard ratio (HR) = 0.51, P < 0.001; HR = 0.43, P < 0.001]. IORT was an independent prognostic determinant for patients with peritoneal metastasis (HR = 0.24, P = 0.011), whereas it was not for those with liver metastasis (HR = 0.78, P = 0.381). Conclusions: The prognostic value of IORT is most prominent in the peritoneal disease. IORT followed by GEM-based chemotherapy is possibly one of the most recommended treatment strategies in unresectable pancreatic cancer. No significant financial relationships to disclose.