Fatal Refractory Radiation-Induced Biliary Stenosis (RIBS) and Liver Abscess Following Carbon-Ion Radiotherapy for Hepatocellular Carcinoma: A Case Report.

Carbon-ion radiotherapy (C-ion RT) is an effective modality for hepatocellular carcinoma (HCC); however, it carries a risk of radiation-induced biliary stenosis (RIBS), particularly for centrally located tumors. We report a rare but potentially fatal case of refractory RIBS following C-ion RT. A patient underwent C-ion RT for HCC located near the hepatic hilum. During long-term follow-up, despite no evidence of local tumor recurrence, the patient developed severe biliary stenosis. Due to the ischemic and rigid nature of RIBS, the stricture was highly resistant to standard endoscopic balloon dilation and repeated plastic stenting. Metallic stents were avoided to prevent complications associated with benign strictures, and surgical or percutaneous interventions were contraindicated due to the patient's poor baseline hepatic reserve and lobar atrophy. The clinical course was complicated by recurrent cholangitis, ultimately culminating in a fatal liver abscess and septic shock driven by the opportunistic pathogen Raoultella ornithinolytica. Because detailed dosimetric parameters were unavailable, definitive causality cannot be established; thus, C-ion RT is considered a significant contributory risk factor. RIBS is a rare but catastrophic late complication of C-ion RT for central HCC. The profound ischemic changes make standard endoscopic management highly challenging, predisposing patients to severe opportunistic infections. This case highlights the necessity of long-term vigilance, risk-adapted patient selection, and cautious multidisciplinary management.