title: Prognostic factors after imatinib secondary resistance: survival analysis in patients with unresectable and metastatic gastrointestinal stromal tumors.
abstract: BACKGROUND
  Patients undergoing imatinib therapy for gastrointestinal stromal tumors (GISTs) show drug resistance during treatment in the late stages. The aims of this study were to determine survival after the appearance of imatinib secondary resistance (ISR) and to identify the prognostic factors.
  
  
  METHODS
  Eligible were patients with unresectable and metastatic GISTs who were diagnosed with ISR and/or underwent treatment for ISR in our institution between 2001 and 2012. A total of 48 patients were enrolled and overall survival was retrospectively analyzed. The Cox proportional hazards model was used to identify the independent prognostic factors. Median follow-up time was 58 months.
  
  
  RESULTS
  As of the cutoff date, 41 of the 48 patients with ISR had died, of which 39 died of GISTs. The overall 1-, 3-, and 5-year survival rates of the 48 patients were 64.6, 32.8, and 20.4 %, respectively, and median survival time was 22 months. The favorable independent prognostic factors identified were long progression-free survival in first-line imatinib therapy (P = 0.04), small diameter of progressive disease (PD) (P = 0.02), and surgical resection of PD (P = 0.01).
  
  
  CONCLUSIONS
  Surgical resection of PD in selected cases could improve prognosis in ISR patients undergoing GIST treatment.
authors.affiliation: Department of Surgery, Sanjo General Hospital, 5-Tsukanome, Sanjo, Niigata, 955-0055, Japan. kandat@herb.ocn.ne.jp.|Division of Digestive and General Surgery, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan. kandat@herb.ocn.ne.jp.
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Kanda
authors.affiliation: Department of Medical Informatics, Niigata University Medical and Dental Hospital, Niigata, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Ishikawa
authors.affiliation: Department of Digestive and General Surgery, Uonuma Institute of Community Medicine, Niigata University Medical and Dental Hospital, Minami-Uonuma, Niigata, Japan.
authors.forename: Shin-Ichi
authors.initials: SI
authors.lastname: Kosugi
authors.affiliation: Department of Surgery, Kashiwazaki Medical Center, Kashiwazaki, Niigata, Japan.
authors.forename: Kyo
authors.initials: K
authors.lastname: Ueki
authors.affiliation: Department of Surgery, Nagaoka Red Cross Hospital, Nagaoka, Niigata, Japan.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Naito
authors.affiliation: Division of Digestive and General Surgery, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
authors.forename: Toshifumi
authors.initials: T
authors.lastname: Wakai
authors.affiliation: Department of Surgical Pathology, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan.
authors.forename: Seiichi
authors.initials: S
authors.lastname: Hirota
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D018450:Disease Progression; D018572:Disease-Free Survival; D019008:Drug Resistance, Neoplasm; D005260:Female; D005770:Gastrointestinal Neoplasms / Q000188:drug therapy* / Q000401:mortality / Q000473:pathology*; D046152:Gastrointestinal Stromal Tumors / Q000188:drug therapy* / Q000401:mortality / Q000556:secondary; D006801:Humans; D000068877:Imatinib Mesylate / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D016019:Survival Analysis; D015996:Survival Rate
chemical_list: D000970:Antineoplastic Agents; D000068877:Imatinib Mesylate
keywords: GIST; Imatinib; Prognosis; Secondary resistance