Radiological Loco‐Regional Treatments for Cholangiocarcinoma: A Systematic Review of the Literature

Cholangiocarcinoma (CCA) is the second most common primary liver cancer and is being diagnosed with increasing frequency worldwide. We performed a systematic review on radiofrequency (RFA), microwave (MWA), irreversible electroporation (IRE), trans-arterial chemoembolization (TACE) and selective internal radiation therapy (SIRT) in CCA. Thirty-one ablation studies (1526 patients), 21 TACE studies (1594 patients), and 38 SIRT studies (1954 patients) were included; most cohorts involved intrahepatic CCA (iCCA) and originated from Asia. For RFA/MWA, overall survival (OS) typically exceeded 25 months and recurrence-free survival (RFS) 7-9 months. The ideal candidate profile for percutaneous ablation was an uninodular iCCA measuring ≤ 2-3 cm developed on cirrhosis. For TACE, median objective response rate (ORR) was 35%, with median OS 11.7 months and RFS of 4 months. Hypervascularity, low tumour burden (< 30%-50% of liver involvement), and preserved liver function were associated with better outcomes and may be used to identify suitable candidates for TACE in case of unresectable iCCA. For SIRT, median ORR was 36.3%, OS 14.5 months, and RFS 8.7 months. A large unilobar tumour with personalised dosimetry appears the best candidate for SIRT in unresectable iCCA, with potential for downstaging to surgery in some cases. However, the literature regarding locoregional treatment is predominantly retrospective and heterogeneous, with inconsistent reporting of staging, cirrhosis, and endpoints, and almost no randomised trials. Locoregional radiological therapies remain viable options for carefully selected, liver-dominant iCCA, but prospective multicenter studies are needed to define indications, and to optimise sequencing and combination strategy with systemic treatments.