title: Effectiveness and safety of tegafur-gimeracil-oteracil potassium (TS-1) for metastatic breast cancer: a single-center retrospective study.
abstract: BACKGROUND
  Tegafur-gimeracil-oteracil potassium (TS-1)is a drug that is used mainly as a third-line treatment or beyond for metastatic breast cancer(MBC). However, there is still insufficient evidence on its clinical effectiveness, and there are very few reports on clinical research using TS-1 up front. In this report, we examined the effectiveness and safety of TS-1 therapy for MBC.
  
  
  METHODS
  The subjects were 46 patients with MBC who were treated with TS-1 between January 2005 and January 2013. These patients were retrospectively examined.
  
  
  RESULTS
  The objective response rate to TS-1 therapy was 30.4%, clinical benefit rate (CBR)was 50.0%, and the median time to treatment failure was 10.7 months. When examined by site, the CBR was high locally (46.2%), in the lymph nodes (40.7%), in the bone (42.9%), and in the lungs and pleura (44.8%). However it was low in the liver(30.0%). The relationship was examined between clinicopathological factors and the effectiveness of TS-1 therapy. The objective response rate (ORR) was significantly higher for patients with disease-free interval (DFI) of 2 years or more (p=0.039), TS-1 therapy used as third-line treatment or earlier (p=0.022), negative HER2 status (p=0.020), and no history of capecitabine (CAP)therapy (p=0.049). The CBR was significantly higher for patients with no visceral metastasis (p=0.032), TS-1 used as third-line treatment or earlier (p=0.019), negative HER2 status (p= 0.045), no history of CAP therapy (p=0.006), and no history of tegafur-uracil/doxifluridine therapy (p=0.031). Multivariate analysis showed that DFI of 2 years or more (p=0.035, odds ratio:0.104)was an independent predictor of effectiveness assessed by ORR. There were only 4 patients in whom the treatment was discontinued due to adverse event, and TS-1 was generally well tolerated.
  
  
  CONCLUSIONS
  TS-1 was highly effective and well tolerated by patients with MBC. Its up-front use might enable the maintenance of satisfactory QOL and the enhancement of its clinical effectiveness.
authors.affiliation: Breast Center, Dokkyo Medical University Koshigaya Hospital.
authors.forename: Kazuo
authors.initials: K
authors.lastname: Ishizuna
authors.forename: Jun
authors.initials: J
authors.lastname: Ninomiya
authors.forename: Toshihisa
authors.initials: T
authors.lastname: Ogawa
authors.forename: Makoto
authors.initials: M
authors.lastname: Kojima
authors.forename: Eiichi
authors.initials: E
authors.lastname: Tsuji
authors.forename: Miho
authors.initials: M
authors.lastname: Kawashima
authors.forename: Miwako
authors.initials: M
authors.lastname: Nozaki
authors.forename: Hidetsugu
authors.initials: H
authors.lastname: Yamagishi
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Ueda
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000009:adverse effects / Q000627:therapeutic use*; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000473:pathology; D004338:Drug Combinations; D006801:Humans; D008875:Middle Aged; D009362:Neoplasm Metastasis; D010094:Oxonic Acid / Q000008:administration & dosage / Q000009:adverse effects; D011725:Pyridines / Q000008:administration & dosage / Q000009:adverse effects; D012189:Retrospective Studies; D005641:Tegafur / Q000008:administration & dosage / Q000009:adverse effects
chemical_list: D004338:Drug Combinations; D011725:Pyridines; C586502:tegafur-gimeracil-oteracil; C079198:S 1 (combination); D005641:Tegafur; D010094:Oxonic Acid