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Carcinoma pancreas with duodenal infiltration is usually not treated with SBRT, due to risk of increased complications like gastrointestinal bleed, ulceration and fistula formation. A retrospective analysis of patients, who were treated with SBRT, was done, to study the incidence of the above said complications  

An IRB approved retrospective analysis of 98 patients of carcinoma pancreas treated with SBRT during 2017 to 2020 was done. Of these 98 patients, 12 patients had duodenal infiltration, on duodenoscopy and Contrast enhanced CT (pancreatic protocol) at baseline.  Patients with adenocarcinoma of head/body of pancreas, a median follow up of 6 months after SBRT, and mucosal duodenal invasion on pre-treatment duodenoscopy and tri-phasic CECT (pancreatic protocol), were included. Dose painted SBRT was delivered. Dose of 25-30 gray/5-6 fractions to tumor abutting the duodenum and up to 42Gray/ 5-6 fractions to tumor/vessel interface was delivered. The analysis evaluated, whether patients with duodenal invasion had increased incidence of grade ≥ 3(G3) gastrointestinal toxicity(GI), ulceration, bleeding or fistula formation.

Of 12 patients with duodenal invasion, 10 had tumours of the head and 2 had in the body of pancreas. 6 patients were Locally advanced and 6 were borderline resectable pancreatic cancer. All patients received 4 to 6 cycles of NACT (FOLFIRINOX n=10, and Gem- Nab Paclitaxel n=3) before SBRT.  All received a dose of 25-30 Gray/5-6fractions to the duodenum- tumour interface and 42 Gray/5-6 fractions to tumour vessel interface, without any intra-fraction or inter-fraction complications. 2(15%) underwent surgery. One patient had pathological complete response and is post treatment 3 years and is still on follow up. None of the patients developed grade 3 GI toxicity, GI bleed, ulcer or fistula. Five patients had grade 1, two patients had grade 2, and five patients had no GI toxicity. There was no association between duodenal invasion and the incidence of G3 toxicity, ulceration and bleeding. Median overall survival was 10 months (range 4-30 months) and median follow up from conclusion of SBRT was 7 months (range 2-26 months)

Duodenal invasion, prior to SBRT did not increase GI bleeding duodenal ulceration, or fistula risk. Our data suggests that pancreatic adenocarcinoma patients with duodenal invasion, can be treated with SBRT using a dose-painting approach.