Efficacy of Conversion Surgery for Initially Unresectable Biliary Tract Cancer That Has Responded to Down-Staging Chemotherapy

Background: Due to the limited efficacy of chemotherapy alone in the treatment of unresectable biliary tract cancer, we performed conversion surgery in patients with unresectable biliary tract cancer who responded to down-staging chemotherapy. Methods: Patients with unresectable biliary tract cancer who initiated chemotherapy between 2007 and 2018 were included in this study. We evaluated the short- and long-term outcomes of patients with initially unresectable biliary tract cancer who underwent conversion surgery. Results: A total of 101 patients with unresectable biliary tract cancers treated with chemotherapy were eligible for the present study. A total of 20 patients eventually underwent conversion surgery; these patients had locally advanced disease in 6 cases, liver metastasis in 6 cases, para-aortic lymph node metastasis in 5 cases, and peritoneal dissemination in 3 cases. The mean operative time was 823 min, and the mean intraoperative blood loss was 1902 mL. Histological R0 resections were performed in 17 patients. Postoperative complications of Clavien–Dindo grade IIIa or higher occurred in 10 patients, with no surgery-associated deaths. The 5-year survival rate was significantly higher in patients who underwent conversion surgery (65.0%) than in those who did not (4.3%, p < 0.001). Conclusions: Conversion surgery for initially unresectable biliary tract cancer resulted in favorable overall survival and was safely performed despite its high surgical invasiveness. Conversion surgery for an initially unresectable biliary tract cancer is worth considering.