Genomic determinants and clinical relevance of cancer-associated thrombosis in biliary tract cancers.

Abstract

e16179 Background: Biliary tract cancers (BTCs) are a group of rare tumors with a dismal prognosis and a complex molecular landscape. In this setting, the incidence and clinical relevance of cancer-associated thrombosis (CAT) is unknown, thus BTCs are not included in common thrombotic risk scores (e.g. Khorana Score). Moreover, retrospective studies highlighted associations between thromboembolic events and some genetic alterations, such as KRAS in lung and colorectal cancer, ALK/ROS1 in lung cancer and IDH1 mutations in glioma. Nevertheless, the impact of different genomic alterations on CAT risk in BTCs patients has never been investigated. The aim of this study was to investigate for the first time the incidence and the clinical relevance of CAT in a cohort of BTC patients. In addition, we investigated the association between tumor genomics and CAT in this patients’ population. Methods: Clinical and genomic data of consecutive BTC patients who underwent extensive molecular profiling with the FoundationOneCDx panel at Fondazione IRCCS Istituto Nazionale dei Tumori di Milano, Italy, were collected. The association between genomic alterations and CAT incidence was investigated with the Fisher exact test, considering alterations occurring in at least 5% of patients. Cox regression was used to analyze the impact of CAT, considered as a time-dependent covariate, on overall survival (OS). Results: 140 patients were included in the analysis, mostly represented by cases of intrahepatic cholangiocarcinoma (77%). CAT occurred in 18 (13%) patients, the majority being pulmonary embolism (28%) and visceral thrombosis (44%). Pathogenic KRAS and BRCA1 mutations were found in 33% and 11% of patients with CAT, resulting significantly associated with an increased risk of thrombosis ( p = 0.041 for both). Patients who experienced CAT showed a significantly poorer OS (HR 3.29, p = < 0.001). Conclusions: This is the first report describing a non-negligible incidence and significant prognostic impact of CAT in BTC patients. Future studies investigating the clinical and molecular risk factors for CAT in this population are needed to tailor thromboprophylaxis in this rare population.