title: Efficacy of S-1 in heavily pretreated patients with metastatic breast cancer: cross-resistance to capecitabine.
abstract: BACKGROUND
  It is not clear what the optimal treatment of chemotherapy is for patients with heavily treated metastatic breast cancer (MBC). We have retrospectively examined the efficacy and safety of S-1 in patients with MBC who had been previously treated with anthracycline, taxane, and capecitabine.
  
  
  METHODS
  Patients with MBC who had been administered S-1, an oral modulated compound containing a fluoropyrimidine derivative, between November 2001 and June 2003 at the Cancer Institute Hospital were retrospectively reviewed. S-1 at a standard dose of 50 mg/body was administered twice daily for four weeks, followed by a two-week rest period. This was repeated every six weeks until disease progression or unacceptable toxicity.
  
  
  RESULTS
  Thirty-five patients were assessed. The patients were heavily pretreated with anthracycline (100%), taxane (paclitaxel or docetaxel) (100%), capecitabine (100%), vinorelbine (71%), and mitomycin (69%). Median follow-up time of patients was 9.6 months (range, 1.2-26.6). ORR was 3% (95% confidence interval: 0-9%), and CBR was 20% (95% confidence interval: 6-33%). Time to treatment failure was 2.8 months. Overall survival was 21.4 months. Grade 1 or 2 adverse events were observed in 17% and 13%, respectively. Grade 3 events occurred as anorexia (9%), nausea (9%), vomiting (9%), diarrhea (14%), fatigue (3%), and elevation of AST/ALT (3%). No grade 3 was seen as hand-foot syndrome. Neither grade 3 nor 4 was observed in bone marrow suppression.
  
  
  CONCLUSIONS
  S-1 was fairly well tolerated, but demonstrated very limited activity in capecitabine-pretreated patients who had already been exposed to anthracycline and taxane. It was suggested that S-1 clinically exhibited cross-resistance to capecitabine.
authors.affiliation: Department of Medical Oncology, The Cancer Institute of Japanese Foundation for Cancer Research, 3-10-6, Ariake, Koto-ku, Tokyo, 135-8550, Japan. yito@jfcr.or.jp
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Ito
authors.forename: Yohei
authors.initials: Y
authors.lastname: Osaki
authors.forename: Nahomi
authors.initials: N
authors.lastname: Tokudome
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Sugihara
authors.forename: Shunji
authors.initials: S
authors.lastname: Takahashi
authors.forename: Takuji
authors.initials: T
authors.lastname: Iwase
authors.forename: Kiyohiko
authors.initials: K
authors.lastname: Hatake
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018943:Anthracyclines / Q000008:administration & dosage; D000964:Antimetabolites, Antineoplastic / Q000627:therapeutic use*; D001859:Bone Neoplasms / Q000188:drug therapy* / Q000556:secondary; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000473:pathology; D001952:Bridged-Ring Compounds / Q000008:administration & dosage; D000069287:Capecitabine; D003841:Deoxycytidine / Q000008:administration & dosage / Q000031:analogs & derivatives; D004338:Drug Combinations; D019008:Drug Resistance, Neoplasm; D005260:Female; D005472:Fluorouracil / Q000008:administration & dosage / Q000031:analogs & derivatives; D006801:Humans; D008113:Liver Neoplasms / Q000188:drug therapy* / Q000556:secondary; D008175:Lung Neoplasms / Q000188:drug therapy* / Q000556:secondary; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000175:diagnosis / Q000188:drug therapy; D009367:Neoplasm Staging; D010094:Oxonic Acid / Q000627:therapeutic use*; D010997:Pleural Neoplasms / Q000188:drug therapy* / Q000556:secondary; D011379:Prognosis; D012189:Retrospective Studies; D015996:Survival Rate; D043823:Taxoids / Q000008:administration & dosage; D005641:Tegafur / Q000627:therapeutic use*; D016896:Treatment Outcome
chemical_list: D018943:Anthracyclines; D000964:Antimetabolites, Antineoplastic; D001952:Bridged-Ring Compounds; D004338:Drug Combinations; D043823:Taxoids; D003841:Deoxycytidine; C079198:S 1 (combination); D005641:Tegafur; C080625:taxane; D010094:Oxonic Acid; D000069287:Capecitabine; D005472:Fluorouracil