Management of biliary tract cancers in early‐onset patients: A nested multicenter retrospective study of the ACABI GERCOR PRONOBIL cohort.

Background & Aims: Accumulating data has shown the rising incidence and poor prognosis of early‐onset gastrointestinal cancers, but few data exist on biliary tract cancers (BTC). We aimed to analyse the clinico‐pathological, molecular, therapeutic characteristics and prognosis of patients with early onset BTC (EOBTC, age ≤50 years at diagnosis), versus olders. Methods: We analysed patients diagnosed with intrahepatic cholangiocarcinoma, extrahepatic cholangiocarcinoma, and gallbladder adenocarcinoma between 1 January 2003 and 30 June 2021. Baseline characteristics and treatment were described in each group and compared. Progression‐free survival, overall survival and disease‐free survival were estimated in each group using the Kaplan‐Meier method. Results: Overall, 1256 patients were included, 188 (15%) with EOBTC. Patients with EOBTC demonstrated fewer comorbidities (63.5% vs. 84.5%, p <.0001), higher tumour stage (cT3–4: 50.0% vs. 32.3%, p =.0162), bilobar liver involvement (47.8% vs. 32.1%, p =.0002), and metastatic disease (67.6% vs. 57.5%, p =.0097) compared to older. Patients with EOBTC received second‐line therapy more frequently (89.5% vs. 81.0% non‐EOBTC, p =.0224). For unresectable patients with BTC, median overall survival was 17.0 vs. 16.2 months (p =.0876), and median progression‐free survival was 5.8 vs. 6.0 months (p =.8293), in EOBTC vs. older. In advanced stages, fewer actionable alterations were found in EOBTC (e.g., IDH1 mutations [7.8% vs. 16.6%]; FGFR2‐fusion [11.7% vs. 8.9%]; p =.029). Conclusions: Patients with EOBTC have a more advanced disease at diagnosis, are treated more heavily at an advanced stage but show similar survival. A distinctive molecular profile enriched for FGRF2 fusions was found. [ABSTRACT FROM AUTHOR]