Biliary duct stenosis after image-guided high-dose-rate interstitial brachytherapy of central and hilar liver tumors : A systematic analysis of 102 cases.

OBJECTIVE: Image-guided high-dose-rate interstitial brachytherapy (iBT) with iridium-192 is an effective treatment option for patients with liver malignancies. Little is known about long-term radiation effects on the bile duct system when central hepatic structures are exposed to iBT. This retrospective analysis investigates the occurrence of posthepatic cholestasis (PHC) and associated complications in patients undergoing iBT.

MATERIALS AND METHODS: We identified patients who underwent iBT of hepatic malignancies and had point doses of ≥1 Gy to central bile duct structures. Patients with known bile duct-related diseases or prior bile duct manipulation were excluded.

RESULTS: 102 patients were retrospectively included. Twenty-two patients (22%) developed morphologic PHC after a median of 17 (3-54) months; 18 of them were treated using percutaneous transhepatic cholangiopancreatography drainage or endoscopic retrograde cholangiopancreatography. The median point dose was 24.8 (4.4-80) Gy in patients with PHC versus 14.2 (1.8-61.7) Gy in those without PHC (p = 0.028). A dose of 20.8 Gy (biological effective dose, BED3/10  = 165/64.1 Gy) was identified to be the optimal cutoff dose (p = 0.028; 59% sensitivity, 24% specificity). Abscess/cholangitis was more common in patients with PHC compared to those without (4 of 22 vs. 2 of 80; p = 0.029). Median survival did not differ between patients with and without PHC (43 vs. 36 months; p = 0.571).

CONCLUSION: iBT of liver malignancies located near the hilum can cause PHC when the central bile ducts are exposed to high point doses. Given the long latency and absence of impact of iBT-induced PHC on median survival, the rate of cholestasis and complications seen in our patients appears to be acceptable.