title: Extreme drug resistance is common after prior exposure to paclitaxel.
abstract: OBJECTIVE
  The platinum-free interval (PFI) is an important entity in the treatment of women with epithelial ovarian cancer. The purpose of this study was to determine on clinical samples whether a taxane-free interval (TFI), as defined by in vitro extreme drug resistance assay, existed in women previously exposed to platinum and taxane chemotherapy.
  
  
  METHODS
  Records were examined from 2003 to 2006 to find all patients with epithelial ovarian cancer who had previous exposure to platinum and taxane therapy. Further examination was done to find all patients who underwent secondary cytoreduction and had their tumor submitted for extreme drug resistance assay.
  
  
  RESULTS
  Thirty-four women meeting the above criteria were found. The mean PFI was 25 months (median 18). The mean TFI was 27 months (median 20). Over 44% of the patients have been exposed to more than just a course of platinum and a course of a taxane. In patients having a PFI of >or=12 months, 38.8% had extreme drug resistance (EDR) to carboplatin and 41.9% EDR to cisplatin. Conversely, in patients having a TFI of >or=12 months, 89.7% had EDR to paclitaxel and 82.8% EDR to docetaxel.
  
  
  CONCLUSIONS
  While only a small percentage have EDR to carboplatin and cisplatin after a PFI of >or=12 months, almost 90% of patients with a TFI>or=12 months showed EDR to paclitaxel in vitro.
authors.affiliation: Indiana Women's Oncology, Division of Gynecologic Oncology, St. Vincent Hospitals-Indianapolis, 8301 Harcourt Road, Suite 201, Indianapolis, Indiana, USA. jgeisler@indianawomensoncology.com
authors.forename: John P
authors.initials: JP
authors.lastname: Geisler
authors.forename: Georgiann C
authors.initials: GC
authors.lastname: Linnemeier
authors.forename: Amanda J
authors.initials: AJ
authors.lastname: Thomas
authors.forename: Kelly J
authors.initials: KJ
authors.lastname: Manahan
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000970:Antineoplastic Agents / Q000494:pharmacology*; D016190:Carboplatin / Q000494:pharmacology; D002945:Cisplatin / Q000494:pharmacology; D000077143:Docetaxel; D018432:Drug Resistance, Multiple; D019008:Drug Resistance, Neoplasm; D005260:Female; D006801:Humans; D008875:Middle Aged; D010051:Ovarian Neoplasms / Q000188:drug therapy*; D017239:Paclitaxel / Q000494:pharmacology*; D043823:Taxoids / Q000494:pharmacology
chemical_list: D000970:Antineoplastic Agents; D043823:Taxoids; D000077143:Docetaxel; D016190:Carboplatin; D017239:Paclitaxel; D002945:Cisplatin