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The toxicity of the gallbladder from hypofractionated and stereotactic body radiation treatment is not well recognized (SBRT). In a retrospective cohort of patients with primary and metastatic liver cancers undergoing ablative-intent, we reported on gallbladder and bile system toxicity.

Between 2018-2021, 55 Patients underwent SBRT of liver lesions in our department. The Patients received 56-66 Gy in 5-12 fractions. No gallbladder dose constraints were used at treatment, and gallbladder volumes and dose-volume histograms were created retrospectively. Attributable toxicity was defined as cholecystitis or perforation without preexisting gallbladder disease. Baseline factors were evaluated using Fisher exact test and the nonparametric K-sample test.

The average duration of follow-up was 18.2 months (range, 3 -36 months).

The biliary system was irradiated with >20 Gy in 45 individuals. Twenty-five individuals had their gallbladders irradiated with more than 50 Gy. Only nine individuals had bile duct stenosis; all had preexisting cholelithiasis and received biliary stenting before RT.

We found no link between gallbladder dosage and toxicity and did not approach the maximum tolerable gallbladder dose in this radiation-treated group. To preserve the gallbladder during ablative and SBR treatments, we propose not limiting the dosage to the gross tumor volume.