Analysis of the clinical benefit of intraoperative radiotherapy in patients undergoing macroscopically curative resection for pancreatic cancer

PURPOSE: To determine the survival of pancreatic cancer patients treated with intraoperative radiotherapy (IORT) and/or external beam radiation therapy (EBRT) following macroscopically curative resection. METHODS AND MATERIALS: One hundred and thirty-eight patients with pancreatic cancer who had undergone potentially curative total or regional pancreatectomy between 1980 and 1997 were retrospectively analyzed. Among the 138 patients, 98 had a pathologically negative surgical margin and the remaining 40 patients had a positive surgical margin. The usual EBRT dose was 45-55 Gy with a daily fraction of 1.5-2.0 Gy. The median IORT dose was 25 Gy in a single fraction. RESULTS: The 2-year cause-specific survival rate of patients with pathologically negative surgical margins was 19%, and that of patients with positive margins was 4% (p < 0.005). Although the median survival time (MST) of patients with negative margins treated with IORT and EBRT was significantly longer than that of those treated with operation alone (17 vs. 11 months), no significant difference in survival curves was observed. In patients with positive surgical margins in peripancreatic soft tissue, the difference between the survival curve of patients treated with surgery alone and that of those treated with surgery and radiation therapy was borderline significant (p < 0.10). Patients receiving intraarterial or intraportal infusion chemotherapy had significantly improved survival rates compared with those who did not receive it (p < 0.05). CONCLUSION: Although the MST was longer in patients with negative margins receiving IORT and EBRT than in those receiving no radiation, improved long-term survival by IORT and/or EBRT was not suggested. In patients with positive margins, our results obtained by IORT/EBRT were encouraging. Randomized studies with much higher patient numbers are necessary to define the role of IORT in curatively resected pancreatic cancer.