Potential radiotherapy-related reactivation of immune checkpoint inhibitor hepatitis.

This report details the reactivation of immune checkpoint inhibitor (ICI)-related autoimmune hepatitis triggered by stereotactic body radiation therapy (SBRT) in a 55-year-old male with hilar cholangiocellular carcinoma. Initially diagnosed in December 2021, the patient underwent successful resection and subsequent adjuvant therapy. Despite stable disease following chemotherapy augmented with durvalumab, he developed grade 3 acute hepatitis after seven cycles of durvalumab. Following a brief prednisolone regimen and normalization of liver tests, SBRT targeting para-aortic lymph nodes was initiated. Remarkably, severe hepatitis reoccurred 7 days after starting SBRT, 88 days following the last durvalumab infusion, necessitating resumed and escalated prednisolone treatment. Another course of SBRT for a newly diagnosed metastatic liver lesion was administered in September 2023, with ongoing prednisolone adjustment. By February 2024, liver tests normalized, but subsequent radiological assessments indicated tumor progression, leading to the reintroduction of chemotherapy. This case underscores the potential of SBRT for activating severe immune-mediated hepatotoxicity in patients treated with ICIs, highlighting the need for careful monitoring and management of such patients. Further, this report highlights the possible survival benefit of the strategic application of SBRT in addition to systematic treatment in recurrent and metastatic cholangiocellular carcinoma.