Does Intraoperative Radiation Therapy Improve Local Tumor Control in Patients Undergoing Pancreaticoduodenectomy for Pancreatic Adenocarcinoma? A Propensity Score Analysis

Background: Locoregional recurrence (LRR) is an important factor after pancreaticoduodenectomy (PD) for pancreatic cancer. IORT administered to the resection bed may improve local tumor control. Methods: We performed a retrospective analysis of patients who underwent PD at Thomas Jefferson University Hospital (TJUH) between 1995 and 2005 to identify patients who underwent resection with and without intraoperative radiation therapy (IORT). Data collected included age, gender, complications, margin status, stage, survival, and recurrence. Unadjusted analyses of the IORT and non-IORT groups were performed using Fisher’s chi-square method for discrete variables and Wilcoxon Rank Sum test for continuous variables. To account for biases in patient selection for IORT, a propensity score was calculated for each patient and adjusted statistical analyses were performed for survival and recurrence outcomes. Results: Between January 1995 and November 2005, 122 patients underwent PD for perimpullary tumors, including 99 pancreatic cancers. Of this group, 37 patients were treated with IORT, and there was adequate follow-up information for a group of 46 patients who underwent PD without IORT. The IORT group contained a higher percentage of Stage IIB or higher tumors (65%) than in the non-IORT group (39.1%), though differences in stage did not reach significance (p = 0.16). There was a non-significant decrease in the rate of LRR in patients who had IORT (39% non-IORT vs. 23% IORT, p = 0.19). The median survival time of patients who received IORT was 19.2 months, which was not significantly different than patients managed without IORT, 21.0 months (p=0.78). In the propensity analyses, IORT did not significantly influence survival or recurrence after PD. Conclusions: IORT can be safely added to management approaches for resectable pancreatic cancer, with acceptable morbidity and mortality. IORT did not improve loco-regional control and did not alter survival for patients with resected pancreatic cancer. IORT is an optional component of adjuvant chemoradiation for pancreatic cancer. In the future, IORT may be combined with novel therapeutic agents in the setting of a clinical trial in order to attempt to improve outcomes for patients with pancreatic cancer. Annals of Surgical Oncology, Volume 16, Edition 8, August, 2009, pages 2116-22, “Does intraoperative radiation therapy improve local tumor control in patients undergoing pancreaticoduodenectomy for pancreatic adenocarcinoma? A propensity score analysis”. Authors: Showalter TN, Rao AS, Anné PR, Rosato FE, Rosato EL, Andrel J, Hyslop T, Xu X, Berger AC