title: Correlation between overall survival and other endpoints in clinical trials of second-line chemotherapy for patients with advanced gastric cancer.
abstract: BACKGROUND
  The correlation between progression-free survival (PFS) or time to progression (TTP) and overall survival (OS) has been evaluated in patients with advanced gastric cancer (AGC) who received first-line chemotherapy. No corresponding analysis has been done in patients who have undergone second-line chemotherapy.
  
  
  METHODS
  We evaluated the correlation between PFS, TTP, objective response rate (ORR), disease control rate (DCR), and OS in patients with AGC who underwent second-line chemotherapy. Correlations were evaluated by Spearman rank correlation coefficient (ρ).
  
  
  RESULTS
  Sixty-four trials, including 10 randomized studies, were selected for analysis. Median PFS/TTP moderately correlated with OS (ρ = 0.56). The correlation tended to be stronger in non-Asian trials (ρ = 0.74) than in Asian trials (ρ = 0.37). ORR and DCR did not strongly correlate with OS (ρ = 0.38 for ORR; ρ = 0.54 for DCR). The hazard ratio of PFS and OS in each of the arms of the 10 randomized studies also showed a low correlation (ρ = 0.36).
  
  
  CONCLUSIONS
  PFS/TTP, ORR, and DCR did not correlate sufficiently with OS to be used as surrogate endpoints in patients with AGC who have undergone second-line chemotherapy. Further research is needed based on individual patient data from ongoing randomized trials.
authors.affiliation: Department of Gastrointestinal Oncology, National Cancer Center Hospital East, Chiba, Japan, kouheis0824@yahoo.co.jp.
authors.forename: Kohei
authors.initials: K
authors.lastname: Shitara
authors.forename: Keitaro
authors.initials: K
authors.lastname: Matsuo
authors.forename: Kei
authors.initials: K
authors.lastname: Muro
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Doi
authors.forename: Atsushi
authors.initials: A
authors.lastname: Ohtsu
mesh_terms: D015415:Biomarkers; D002986:Clinical Trials as Topic; D018450:Disease Progression; D006801:Humans; D015201:Meta-Analysis as Topic; D011379:Prognosis; D016879:Salvage Therapy; D013274:Stomach Neoplasms / Q000188:drug therapy / Q000401:mortality* / Q000473:pathology; D015996:Survival Rate
chemical_list: D015415:Biomarkers