{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,7]],"date-time":"2026-10-07T11:59:01Z","timestamp":1791374341543,"version":"4.3.1"},"reference-count":22,"publisher":"Springer Science and Business Media LLC","license":[{"start":{"date-parts":[[2026,10,7]],"date-time":"2026-10-07T00:00:00Z","timestamp":1791331200000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"},{"start":{"date-parts":[[2026,10,7]],"date-time":"2026-10-07T00:00:00Z","timestamp":1791331200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"}],"content-domain":{"domain":["link.springer.com"],"crossmark-restriction":false},"short-container-title":["Int J Clin Oncol"],"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:sec>\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>Adjuvant S-1 chemotherapy (ASC) has become the standard postoperative treatment for biliary tract cancer (BTC) in Japan following publication of the results of the ASCOT study, a recent nationwide randomized controlled study. However, recurrence remains common, and risk factors specific to patients treated with ASC are unclear.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>We retrospectively investigated the data of 56 patients with resected BTC at our institution between August 2021 and October 2023. Recurrence-free survival (RFS), overall survival (OS), and treatment safety were evaluated. Cox proportional hazards regression analysis was performed to identify the risk factors for shorter RFS.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>Over a median follow-up of 22.6\u00a0months, 15 patients (26.8%) developed recurrence. The 12- and 24-month RFS rates were 84.8% and 71.6%, respectively, and the 12- and 24-month OS rates were 92.4% and 85.7%, respectively. Both univariate and multivariate analyses identified poorly differentiated tumor histology as a significant risk factor for shorter RFS. In addition, univariate analysis, but not multivariate analysis, also identified elevated pre-ASC serum CA19-9 levels (\u2265\u200937 U\/mL) as a significant risk factor for shorter RFS. Adverse events of \u2265 grade 3 occurred in 3.6% of patients receiving ASC.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>Poorly differentiated tumor histology may be a risk factor for shorter RFS in patients with resected BTC treated with ASC.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1007\/s10147-026-03207-8","type":"journal-article","created":{"date-parts":[[2026,10,7]],"date-time":"2026-10-07T11:48:53Z","timestamp":1791373733000},"update-policy":"https:\/\/doi.org\/10.1007\/springer_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Risk factors for shorter recurrence-free survival in patients with resected biliary tract cancer treated with adjuvant S-1 chemotherapy"],"prefix":"10.1007","author":[{"given":"Tomonao","family":"Taira","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3754-9027","authenticated-orcid":false,"given":"Mitsuhito","family":"Sasaki","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Go","family":"Igarashi","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kanae","family":"Inoue","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Taro","family":"Shibuki","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tomoyuki","family":"Satake","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Masataka","family":"Amisaki","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hideaki","family":"Takahashi","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hiroshi","family":"Imaoka","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Shuichi","family":"Mitsunaga","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Masashi","family":"Kudo","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Motokazu","family":"Sugimoto","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Shin","family":"Kobayashi","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Naoto","family":"Gotohda","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Masafumi","family":"Ikeda","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"297","published-online":{"date-parts":[[2026,10,7]]},"reference":[{"issue":"1","key":"3207_CR1","doi-asserted-by":"publisher","first-page":"13","DOI":"10.5009\/gnl15568","volume":"11","author":"B Blechacz","year":"2017","unstructured":"Blechacz B (2017) Cholangiocarcinoma: current knowledge and new developments. 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MS received research funding from AstraZeneca, Boehringer Ingelheim and Taiho Pharma, and received speaker honoraria from AstraZeneca, MSD, ASAHI INTECC co.,ltd and Century Medical, Inc. KI received speaker honoraria from Chugai Pharmaceutical Co., Ltd. TaS received research funding from Labcorp Genetics, received speaker honoraria from AstraZeneca and Novartis. TSatake received research funding from Nihon Servier Co., Ltd. and Ono Pharmaceutical Co., Ltd., and speaker honoraria from AstraZeneca, Chugai Pharmaceutical Co., Ltd., and Guardant Health, Inc. HI received research funding from Ono Pharmaceutical, Servier, Novartis, Boehringer Ingelheim, and the National Cancer Center Research and Development Fund (Grant Number 2025-A-16); provided expert testimony for Kaneka Medix; served on advisory boards for Servier; received speaker honoraria from Servier, Yakult Honsha, Boston Scientific, Kaneka Medix, SB KAWASUMI LABORATORIES, AstraZeneca, and Novartis; and received medical writing honoraria from Medico\u2019s Hirata. SM received research funding from Chugai pharmaceutical co., Ltd., TORAY industries Inc., Ajinomoto co., Inc., Astellas Pharma Inc., Ono pharmaceutical co., Ltd., Mitsui Chemicals, Inc., Pfizer Inc., Tensegrity Pharma, Taiho innovations, and Taiho Pharma; provided expert testimony for Pfizer Inc.,; served on advisory boards for Taiho Pharma and Tensegrity Pharma; received speaker honoraria from AstraZenaca and Astellas Pharma Inc.; and had patents for a method for detecting pancreatic cancer using cluster of differentiation 276, a method for predicting prognosis of a patient with skeletal muscle loss or efficacy of nutritional therapy for a patient with skeletal muscle loss, and a method for predicting therapeutic effect of combination therapy of IL-6 inhibitor and chemotherapy in patients with pancreatic cancer. MI received research funding from AstraZeneca, Abbvie, Bayer, Bristol Myers Squibb, Chugai, Chiome Bioscience, Delta-Fly Pharma, Eisai, Eli Lilly Japan, Invitae, MSD, J-Pharma, Merck biopharma, Merus N.V., Novartis, Nihon Servier, Ono, Syneos Health, Rakuten Medical, and Taiho, consulted AbbVie, AstraZeneca, Astellas, Bristol-Myers Squibb, Boehringer Ingelheim, GlaxoSmithKline, Guardant Health Japan, Chugai, MSD, Nihon Servier, and Novartis, and received speaker honoraria from AstraZeneca, Chugai, Eisai, Eli Lilly Japan, EA Pharma, Guardant Health Japan, Incyte Biosciences Japan, MSD, Nihon Servier, Novartis, Nobel pharma, Nippon Kayaku, Ono, Taisho Pharmaceutical, Teijin, Takeda, Taiho, and Yakult. The other authors have no disclosures to report.","order":1,"name":"Ethics","label":"Conflict of interest","group":{"name":"EthicsHeading","label":"Declarations"}},{"value":"This study was conducted with the approval of the Institutional Review Board of the National Cancer Center (#2020-209) and in accordance with the principles laid down in the Declaration of Helsinki. The ethics committee of our hospital waived the need for obtaining consent from the patients, since this work involved retrospective use of anonymized patient data.","order":2,"name":"Ethics","label":"Ethical approval","group":{"name":"EthicsHeading","label":"Declarations"}}]}}