Stereotactic body radiation therapy is associated with improved overall survival compared to chemoradiation or radioembolization in the treatment of unresectable intrahepatic cholangiocarcinoma

BACKGROUND: Intrahepatic cholangiocarcinoma (ICC) is a highly lethal malignancy. For patients with locally advanced, unresectable disease, numerous liver-directed therapy options exist, including chemoradiation (CRT), stereotactic body radiation therapy (SBRT), and transarterial radioembolization (TARE). There is no randomized data to inform clinicians regarding the optimal treatment modality. METHOD: We used the National Cancer Database (NCDB) to study the overall survival (OS) of patients with ICC treated with CRT, SBRT, and TARE. We used Cox proportional hazards modeling and inverse probability of treatment weighting (IPTW) to account for confounding variables. RESULTS: We identified 170 patients with unresected ICC treated with SBRT (n = 37), CRT (n = 61), or TARE (n = 72). SBRT was associated with higher OS compared to CRT (hazard ratio [HR] = 0.37; 95% confidence interval [CI] 0.20–0.68; p = 0.001) and TARE (HR = 0.40; 95% CI 0.22–0.74; p = 0.003). On multivariable analysis, SBRT remained associated with higher OS compared to CRT (HR = 0.44; 95% CI 0.21–0.91; p = 0.028) and TARE (HR = 0.42; 95% CI 0.21–0.84; p = 0.014). After IPTW (Bonferroni-adjusted significance threshold, α = 0.017), SBRT again had a statistically significant association with higher OS compared to CRT (HR = 0.22; 95% CI 0.11–0.44; p < 0.0001) and was nominally associated TARE (HR = 0.58; 95% CI 0.37–0.91; p = 0.019). CONCLUSIONS: We found SBRT is associated with higher OS when compared to CRT or TARE for the treatment of unresectable ICC. Due to the retrospective nature of the study and potential selection bias, these findings should be evaluated prospectively.