title: A pathological complete response after combined chemotherapy of gemcitabine and S-1 in advanced biliary tract cancer with para-aortic lymph nodes metastasis: a case report.
abstract: BACKGROUND
  Biliary tract cancer is a rare malignancy that carries poor prognosis. Complete surgical resection is the only curable treatment. However, biliary tract cancer patients are often diagnosed with advanced stages and treated in systemic chemotherapy or palliative treatment settings rather than curative surgery.
  
  
  METHODS
  This case report describes a pathological complete response of advanced biliary tract cancer achieved after 2 years of intensive combined chemotherapy with gemcitabine and S-1. A 70-year-old female patient who developed severe stenosis in the middle common bile duct with para-aortic lymph nodes swelling was diagnosed with advanced extrahepatic biliary tract cancer that includes metastatic para-aortic lymph nodes and treated with combined chemotherapy of gemcitabine and S-1. After 32 courses of the combined chemotherapy, substantial shrinkage of these enlarged lymph nodes were confirmed and she underwent pylorus-preserving pancreaticoduodenectomy. The pathological examination revealed no viable neoplastic cells in the common bile duct or lymph nodes. She did not receive any further adjuvant chemotherapy. No recurrent lesions have been detected for 48 months after the primary surgery.
  
  
  CONCLUSIONS
  This case shed light on the probability of conversion and/or adjuvant surgery for biliary tract cancer with novel systemic chemotherapy regimens.
authors.affiliation: Department of Surgery, Kyorin University School of Medicine, 6-20-2 Shinkawa, Mitaka, Tokyo, 181-8611, Japan. watanabe_t@ks.kyorin-u.ac.jp.
authors.forename: Takeshi
authors.identifier: http://orcid.org/0000-0001-6380-5242
authors.initials: T
authors.lastname: Watanabe
authors.affiliation: Department of Medical Oncology, Kyorin University School of Medicine, Tokyo, Japan.
authors.forename: Junji
authors.initials: J
authors.lastname: Furuse
authors.affiliation: Department of Medical Oncology, Kyorin University School of Medicine, Tokyo, Japan.
authors.forename: Naohiro
authors.initials: N
authors.lastname: Okano
authors.affiliation: Department of Surgery, Kyorin University School of Medicine, 6-20-2 Shinkawa, Mitaka, Tokyo, 181-8611, Japan.
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Suzuki
authors.affiliation: Department of Pathology, Kyorin University School of Medicine, Tokyo, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kamma
authors.affiliation: Department of Surgery, Kyorin University School of Medicine, 6-20-2 Shinkawa, Mitaka, Tokyo, 181-8611, Japan.
authors.forename: Masanori
authors.initials: M
authors.lastname: Sugiyama
keywords: Biliary tract cancer; Chemotherapy; Conversion surgery; Gemcitabine; Pathological complete response; S-1