Background
Retrospective series. 79 patients with locally advanced extrahepatic cholangiocarcinoma (eCCA, n=45) or intrahepatic cholangiocarcinoma (iCCA, n=34) treated with SBRT at UCLA from 2009 to 2015. Both primary (unresectable) and recurrent/oligometastatic disease included. Patients who received SBRT as definitive or salvage therapy after prior RT or surgery.
Interventions and follow up
Arm A: SBRT (various fractionations, median 45 Gy/3 fx for eCCA; 45 Gy/3–5 fx for iCCA)
Arm B: N/A — single-arm retrospective
Primary endpoint: Local control (LC) and overall survival
mFollow up: 15 month
Arm B: N/A — single-arm retrospective
Primary endpoint: Local control (LC) and overall survival
mFollow up: 15 month
Results
1-year LC: 73% (eCCA), 78% (iCCA)
Median OS: 10.4 months (eCCA), 17.3 months (iCCA)
1-year OS: 46% (eCCA), 66% (iCCA)
Median OS: 10.4 months (eCCA), 17.3 months (iCCA)
1-year OS: 46% (eCCA), 66% (iCCA)
Adverse events
Main adverse events: Grade 3+ acute toxicity: 10% eCCA, 6% iCCA. No grade 4/5 treatment-related events. Duodenal and gastric toxicity was a concern in eCCA cases adjacent to bowel.
Conclusions
SBRT for both extrahepatic and intrahepatic cholangiocarcinoma achieves reasonable 1-year local control (73–78%) with acceptable toxicity. Outcomes are better for iCCA than eCCA, likely reflecting greater distance from critical bowel structures in most iCCA cases.
Key Limitations
Key Limitations: Retrospective series with heterogeneous population (primary vs recurrent/oligometastatic), fractionation schemas, and prior treatment histories. Small sample size with short follow-up. No standardized fractionation protocol limits dose-response conclusions. Proximity to duodenum/stomach limits dose escalation for perihilar and distal eCCA. Selection bias likely.
Clinical Context
SBRT for cholangiocarcinoma remains an area of active investigation. For iCCA, ablative doses (BED >80.5 Gy per Tao 2015) are preferred when normal liver volume permits. For eCCA, dose constraints to bowel often limit ablative dosing. SBRT is increasingly used for locally recurrent cholangiocarcinoma after resection, particularly when re-irradiation is being considered. The ongoing ABC-08 and similar trials are investigating systemic + local therapy combinations.
References