Preoperative stereotactic radiotherapy to prevent pancreatic fistula in high-risk patients undergoing pancreatoduodenectomy (FIBROPANC): prospective multicentre phase II single-arm trial.

Abstract

Background: Postoperative pancreatic fistula is the main driver of morbidity and mortality after pancreatoduodenectomy. In high-risk patients, the rate of postoperative pancreatic fistula approaches 50%, whereas it is below 5% in patients with pancreatic cancer who receive neoadjuvant chemoradiotherapy. The aim of this study was to evaluate the safety, feasibility, and efficacy of preoperative stereotactic body radiotherapy on the pancreatic neck transection margin in high-risk patients undergoing pancreatoduodenectomy to prevent postoperative pancreatic fistula.

Methods: In this prospective multicentre open-label single-arm trial (progressing from a safety run-in phase to a phase II design), patients undergoing pancreatoduodenectomy for neoplasms other than pancreatic ductal adenocarcinoma received a single preoperative stereotactic body radiotherapy dose of 12 Gy. Primary endpoints included safety (less than or equal to 15% grade 3-5 toxicity), feasibility (a significant change in pancreatic texture measured using a durometer), and efficacy (a 15% reduction in the grade B/C postoperative pancreatic fistula rate compared with patients from the Dutch Pancreatic Cancer Audit who were eligible but not included in this study). Secondary endpoints assessed tissue fibrosis (collagen density).

Results: Overall, 38 patients were included, of whom 33 (87%) completed the study protocol and were included in the per-protocol analysis. The safety cut-off was met, with 3% grade 3-5 toxicity. Pancreatic tissue treated with stereotactic body radiotherapy showed increased firmness using a durometer (median of 47 (interquartile range 36-57) versus 37 (interquartile range 30-41) Shore OO units; P < 0.001) and a higher collagen density (median of 6.1% (interquartile range 4.4%-9.5%) versus 4.6% (interquartile range 2.5%-7.4%); P = 0.003). The grade B/C postoperative pancreatic fistula rate with stereotactic body radiotherapy was 57.6% (95% c.i. 41% to 74%), compared with 34% (95% c.i. 27% to 42%) in audit controls (P = 0.011).

Conclusion: Preoperative stereotactic body radiotherapy is safe in high-risk patients undergoing pancreatoduodenectomy and increases parenchymal firmness and fibrosis, but fails to show evidence of efficacy.