Biliary tract cancers: understudied and poorly understood.

Biliary tract cancers are a heterogeneous group of cancers that arise in either the intra- or extrahepatic bile ducts or the gallbladder. Local therapy with surgical resection and perhaps radiation therapy is used for localized disease. There is no known effective adjuvant therapy, although various combinations have been used clinically without definitive data showing a benefit. The most standard chemotherapy for metastatic disease is gemcitabine plus cisplatin based on a single positive randomized trial. Genetic mutations that may lead to better, targeted therapy choices are being identified, albeit with variable frequency. Early studies of targeted agents have been negative, but these were in unselected patients where it was unknown whether the target was activated in any individual patient. Careful selection of patients enrolling onto trials of targeted agents will make the subsets of biliary tract cancers even smaller but is likely necessary to improve outcomes from these deadly diseases.