[Current status of adjuvant therapy for biliary tract cancer]

While surgical resection remains the only potentially curative treatment for biliary tract cancer (BTC), most cases are discovered at an advanced stage and radical resection is possible in only a limited number. Furthermore, most patients develop recurrence even after curative resection. Therefore, effective adjuvant therapies including chemotherapy, radiotherapy, immunotherapy, and photodynamic therapy are necessary to improve the survival and quality of life (QOL) of patients with BTC. A few randomized controlled trials have demonstrated the survival benefit of chemotherapy in patients with unresectable BTC. The combination of gemctitabine and cisplatin is considered the standard treatment for patients with locally advanced or metastatic BTC, according to the results of a randomized phase III study (ABC-02) in the UK. There are no adequate data supporting any second-line therapy, radiotherapy, or adjuvant chemotherapy after surgical resection. Downsizing chemotherapy and subsequent surgical resection for initially unresectable locally advanced BTC may have potential for disease eradication as a new multidisciplinary approach. Well-designed prospective trials in this field should be organized through multicenter and international collaborations to improve the survival and QOL of patients with BTC.