Epidemiological characterization of biliary tract cancer patients from the Spanish RETUD Registry.

503 Background: Biliary tract cancer (BTC) is a heterogeneous group of tumors, including cholangiocarcinoma (intra and extrahepatic) and gallbladder carcinoma (GC). We describe the epidemiology of BTC patients (pt) from the RETUD registry. Methods: We evaluated a large real-world cohort of pt diagnosed with BTC between January 1, 2017, and May 30, 2025. Analyses were based on first therapeutic approach as follows: resectable disease (RD) for patients with neoadjuvant/adjuvant therapy and/or radical treatment (surgery and/or locoregional therapy); and advanced disease (AD) for former patients who relapsed and those initially treated with first line therapy with/without other locoregional treatments. Analysis comprised demographic and clinical characteristics, tumor molecular profile, therapeutic procedures and efficacy outcomes (EO). Time to relapse (TTR) for RD, progression-free survival (PFS) for AD and overall survival (OS) for both were estimated using the Kaplan-Meier method. Results: A total of 1756 pt from 40 centers were classified as RD (695) or AD (1450). 389 (55,9%) pt were initially RD but progressed to AD. Median (m) age at diagnosis (dx) was 67.4 years (y), with 44.3% of women. Most frequent tumor locations at dx were intrahepatic (53.0%) and GC (15.5%). Distant metastasis in AD pt occurred primarily in liver (65.1%). 89.3% received chemotherapy, 10.7% were treated with immunotherapies, 6.3% received targeted therapies, and 7.7% of pt took part in at least one clinical trial. Biomarkers were determined in 553 pt (31.5%). ESCAT-I alterations were found in 176 pt (31.8%), most frequent ones are shown in table 1. RD pt: surgery was performed in 95.7%, locoregional therapy in 15.1% and 68.9% and 5.0% received adjuvant and neoadjuvant therapy respectively. With a m (p25, p75) follow-up of 23.9 months (mo) (14.4, 39.5), mOS was 33.0 mo (95% CI 30.2-38.9). mTTR was 19.4 mo (95% CI 17.3-22.2). AD pt: 1st and 2nd lines were administered to 96.4% and 42.6% pt. Most common schemes were CISGEM and FOLFOX, respectively. Thromboembolic events occurred in 17.3% of AD pt. With a m (p25, p75) follow-up of 13.2 mo (6.7, 22.9), mOS was 10.4 mo (95% CI 9.7-11.2). 1st line mPFS was 5.3 mo (95% CI 4.9-5.6). All pt: There were differences in mOS by age groups; 20.9 mo (95% CI 16.8-26.9) in