Single center experience using stereotactic body radiation therapy (SBRT) on orthotopic liver transplant protocol for unresectable cholangiocarcinoma.

Purpose: To evaluate tolerability, pathologic response, and disease outcomes utilizing pre-operative stereotactic body radiation therapy (SBRT) followed by consolidation chemotherapy (CHT) prior to orthotopic liver transplant (OLT) in unresectable cholangiocarcinoma (CCA).

Methods: This was a retrospective chart review of patients treated on OLT protocol at a single tertiary center from 2012 to 2019. Patients received pre-operative SBRT (40-50 Gy in 5 fractions) followed by CHT until progression or OLT. Progression-free survival (PFS) and overall survival (OS) were compared via log-rank test and Cox proportional hazards regression.

Results: 26 patients (84.6% hilar, 15.4% intrahepatic) were identified for analysis. Eight patients (30.8%) patients developed acute toxicity after SBRT, mostly grade 1 nausea. Nine (34.6%) patients underwent OLT of which 4 (44.4%) achieved a pathologic complete response (pCR). Five (55.6%) OLT patients, including 2 pCR, developed recurrence at a median time of 49.9 weeks after OLT. 3-year OS for the OLT and dropout cohort was 75% and 9%, respectively (p < 0.0001). OS in hilar tumors only was statistically different for those that achieved a pCR (p = 0.014).

Conclusions: Pre-operative SBRT is a well-tolerated and effective radiation technique as part of OLT protocol for unresectable CCA and conferred in a pCR rate of 44% within our cohort.