Prognostic Implications of Intraoperative Radiotherapy for Unresectable Pancreatic Cancer

Background/Aims: To assess the prognostic effect of intraoperative radiotherapy (IORT) in unresectable pancreatic cancer. Methods: We reviewed 198 patients with unresectable pancreatic cancer, which was found during experimental laparotomy. Liver metastasis was observed in 70 patients, peritoneal metastasis in 44, liver and peritoneal metastasis in 23 and locally advanced tumor in 61. Treatment consisted of IORT with or without postoperative chemotherapy. Overall survival (OS) and prognostic factors were evaluated for each pattern of disease spread. Results: IORT was performed in 120 patients, and chemotherapy was administered in 80. Sixty patients did not receive either treatment. OS in the untreated group was significantly inferior to that for IORT alone and IORT plus gemcitabine (GEM)-based chemotherapy. IORTand 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) but not for those with liver metastasis (HR = 0.78, p = 0.381). Conclusion: IORT followed by GEM-based chemotherapy is the recommended treatment strategy in unresectable pancreatic cancer.