title: Tumor Growth Kinetics Before and After First-line Chemotherapy in Metastatic Castration-resistant Prostate Cancer: A Prostate-specific Antigen-based Retrospective Analysis.
abstract: The role of the tumor growth fraction has been investigated poorly in metastatic castration-resistant prostate cancer (mCRPC). The aim of this study was to assess whether some prostate-specific antigen (PSA)-related variables of tumor cell kinetics predict the overall survival in early and late mCRPC, and to explore changes in the tumor growth fraction after chemotherapy.
  
  
  
  A retrospective analysis of 3 tumor cell kinetic variables in patients with mCRPC receiving first-line chemotherapy has been performed. The PSA-related tumor growth rate, the log ratio, and the tumor response have been measured at 3 different times. A further analysis has been performed after stratification by the Gleason score and chemotherapy. Finally, tumor growth after progression to chemotherapy has been explored.
  
  
  
  G at castration resistance is significantly associated with survival after chemotherapy among patients with a low Gleason score (r=-0.650, P-value=0.022). At the time of first-line chemotherapy, both G and PSA response rates report a significant relationship with survival. At the time of postchemotherapy progression, only the G after 12 weeks of chemotherapy maintains a relationship with survival in patients with a low Gleason score (r=-0.483, P-value=0.023); in particular, a tumor growth rate <-0.5%/day appears to be associated with a poor postprogression survival. Despite the lack of correlation between postprogression G and postprogression survival, the response to chemotherapy defines 2 groups with different growth characteristics.
  
  
  
  Among patients with mCRPC, tumor cell kinetics appears to be able to predict the outcome, especially in tumors with a low Gleason score.
authors.affiliation: Division of Medical Oncology, G. Borea Hospital, Sanremo, Imperia, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Colloca
authors.forename: Antonella
authors.initials: A
authors.lastname: Venturino
authors.forename: Domenico
authors.initials: D
authors.lastname: Guarneri
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D018450:Disease Progression; D006801:Humans; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D017430:Prostate-Specific Antigen / Q000097:blood*; D064129:Prostatic Neoplasms, Castration-Resistant / Q000188:drug therapy / Q000401:mortality / Q000473:pathology*; D012189:Retrospective Studies
chemical_list: D000970:Antineoplastic Agents; D017430:Prostate-Specific Antigen