Intra-operative radiation for pancreatic cancer: Initial experience at the Hadassah Medical Center.

Abstract

634 Background: Prognosis following surgery for pancreatic cancer (PC) remains poor. Local recurrence is common and negatively impacts survival rate. In an effort to improve local control and potentially improve survival, we have adopted a strategy of adding intra-operative electron radiation therapy (IOeRT) to selected patients undergoing pancreatic resection (PR) for PC. Here we report our initial experience with this treatment modality. Methods: 14 patients (10 male, 4 female), age between 44 - 81 years (mean 66.17), who underwent PR (Head 7, Body7) between 1/2021-1/2023 were included in this analysis. Patients selected for IOeRT included patients that according to surgeon assessment were at risk not to achieve satisfactory resection margins by surgery alone. All had resectable or borderline resectable disease according to standard criteria. 8 patients underwent pre-op chemotherapy followed by stereotactic body radiotherapy (SBRT) to a dose of 25-40 Gy in 5 fractions to the tumor and regional lymphatics followed by PR (5 Whipple, 3 distal pancreatectomy) and IOeRT, 3 patients received preop SBRT followed by PR (3 distal pancreatectomy) + IOeRT, 2 patients underwent PR (whipple 1, distal pancreatectomy 1) + IoeRT, and 1 received neoadjuvant chemotherapy followed by SBRT only and did not undergo surgery due to tumor progression. Immediately following resection, mobile IOeRT accelerator using a 40-80mm applicator with a level of 0-15 degrees was directed at the tumor bed deemed at high risk for recurrence. 10-20 Gy was delivered using 6-8 MeV electrons to the 90% isodose line at the discretion of the treating radiation oncologist. Data including serial imaging, genomic analysis, radiation protocol, complications, pathological results and outcome was collected for analysis. Results: Mean follow up was 9.7 months (2-21). 8 patients are alive: 7 pts with no evidence of disease and 1 pt with liver metastases. 6 patients died: 4 with distant metastatic disease, 1 from disease progression prior to surgery and 1 from early post-op sepsis. Negative surgical margins were achieved in 10 patients of which 2 mutated BRCA gene carriers showed complete pathological response (both who received combined neoadjuvant chemotherapy followed by SBRT). Post-operative complications possibly attributed to RT included hepatic artery occlusion (1 pt), portal vein stenosis (1 pt) and prolonged GI tract dysfunction (1pt). Conclusions: Combining RT with resection appears feasible and safe. Our data possibly show a reduction in local recurrence following resection of PC, however, longer follow up is necessary. Refinements in patient selection and treatment protocol may further improve outcomes. Larger scale studies are required to determine the benefit of this modality.