Stereotactic Body Radiotherapy (SBRT) Induced Pancreatic Atrophy for Prevention of Post Operative Pancreatic Fistulae (POPF) After Pancreatoduodenectomy in Very High-Risk Patients (STEREOPANC)

Pancreatic fistula is a frequent (13-40%), and potentially life-threatening complication after pancreatic surgery. Most of the mortality after pancreatic surgery is attributable to failure to rescue after pancreatic leak. Soft texture of pancreatic parenchyma (OR = 4.24) and ≤ 3mm pancreatic duct (OR = 3.14) are the strongest predictors of clinically relevant postoperative pancreatic fistula. In very high-risk patients, with soft pancreas and MPD diameter ≤ 3mm, the risk of B/C fistula is exceedingly high, over 40%. Mortality associated with grade C fistula is as high as 25%.

Prolonged duct occlusion causes dilatation of the main pancreatic duct and pressure in the ducts and parenchyma. The enduring high pressure further results in fibrotic changes, exocrine and endocrine insufficiency, defined as athropy of the parenchyma (hard texture). Hard texture of the pancreas can be seen as a surrogate for athropic gland, which is the one absolute factor protecting from POPF: if the exocrine function has run dry, a B/C fistula cannot develop.

SBRT denotes a highly precise radiotherapy method. SBRT delivery techniques enable high doses to target volume and better protection for surrounding normal tissues when compared to conventional external radiation therapy. Radiotherapy induces fibrosis in target organs. We hypothesize, that SBRT directed at the remnant pancreas would cease the exocrine production of pancreas. When considering feasibility and toxicity, SBRT is directly linked to better quality of life due to lesser fractions, and grade 3 toxicity rates are significantly lower than with external RT.

The primary aim of the study is to evaluate the effect of preoperative remnant pancreas SBRT on the rate of B/C vs no preoperative intervention for very high-risk patients scheduled for pancreatoduodenectomy.

The secondary aims include extent of pancreatic fibrosis as assessed by magnetic resonance imaging (MRI) and EUS elastography, SBRT related early and late adverse events (CTCAE), complications of surgery (Clavien-Dindo), postoperative mortality, length of stay, readmissions, SBRT effects on endocrine and exocrine pancreatic function (pre SBRT vs post SBRT), cost analysis, and radiological and histopathological changes induced by SBRT.