The state of therapy modalities in clinic for biliary tract cancer

Biliary tract cancers (BTCs) include intrahepatic cholangiocarcinoma (iCCA), perihilar and distal cholangiocarcinoma (pCCA and dCCA), and gallbladder carcinoma based on the epithelial site of origin. BTCs are highly aggressive tumors associated with poor prognosis due to widespread metastasis and high recurrence. Surgery is the typical curative-intent treatment, yet the cornerstone of cure depends on the anatomical site of the primary tumor, and only a minority of patients (approximately 30%) has an indication necessitating surgery. Similarly, only a small subset of carefully selected patients with early iCCA who are not candidates for liver resection can opt for liver transplantation. Chemotherapy, target therapy, and immunotherapy are the main treatment options for patients who have advanced stage or unresectable disease. The genetic background of each cholangiocarcinoma subtype has been accurately described based on whole gene exome and transcriptome sequencing. Accordingly, precision medicine in targeted therapies has been identified to be aimed at distinct patient subgroups harboring unique molecular alterations. Immunotherapy such as immune checkpoint inhibitors (ICIs) was identified as antitumor responses in a minority of select patients. Current studies indicate that immunotherapy of adoptive cell therapy represents a promising approach in hematological and solid tumor malignancies, yet clinical trials are needed to validate its effectiveness in BTC. Herein, we review the progress of BTC treatment, stratified patients according to the anatomic subtypes of cholangiocarcinoma and the gene drivers of cholangiocarcinoma progression, and compare the efficacy and safety of chemotherapy, targeted therapy, and immunotherapy, which will be conducive to the design of individualized therapies.