Promises and Pitfalls of ctDNA testing in the Management of Cholangiocarcinoma.

Diagnosis and treatment of cholangiocarcinoma is often limited by the availability of tissue biopsies for genomic analysis. Liquid biopsies using blood circulating tumor DNA (ctDNA) have emerged as a valuable and non-invasive alternative to conventional testing. ctDNA analysis has advanced the treatment paradigm for cholangiocarcinoma (CCA) by identifying targetable mutations and molecular mechanisms of treatment resistance. Additionally, it has shown preliminary promise in stratifying patients for adjuvant systemic therapy and enabling earlier detection of relapse. However, current ctDNA platforms face biological and technical challenges that limit their sensitivity for certain mutation types (i.e. gene fusions and amplifications), which are commonly found in CCA. To overcome these hurdles, new sequencing techniques and analytic methods involving artificial intelligence, epigenetic profiling, and diverse reference genomes are being developed. These advanced technologies underscore the promise of ctDNA testing as an indispensable tool in the management and study of CCAs.