title: Changes in prognostic significance and predictive accuracy of Gleason grading system throughout PSA era: impact of grade migration in prostate cancer.
abstract: OBJECTIVE
  To describe the changes in the Gleason grading system over time and evaluate how a shift in Gleason grading has affected the overall predictive accuracy of the system in predicting biochemical disease-free survival after radical prostatectomy.
  
  
  METHODS
  The Columbia University Urologic Oncology Database was reviewed, and 1515 patients who met the inclusion criteria were identified who had undergone radical prostatectomy from 1988 to 2004. The patients were divided into two time cohorts (1988 to 1997 and 1998 to 2004). To determine whether a shift in the Gleason sum distribution has occurred, a chi-square test was performed. Survival curves and log-rank tests were used to compare the biochemical disease-free survival between cohorts stratified by the Gleason sum. To estimate the predictive ability of the Gleason system over time, concordance indexes were calculated.
  
  
  RESULTS
  A shift toward greater Gleason sums over time was confirmed using the chi-square test (P <0.001). A significant difference was observed in biochemical disease-free survival between the two time cohorts for those with Gleason sum 6 cancer (P <0.01). The concordance indexes corresponding to Gleason sum alone for each time cohort were 0.71 and 0.87, demonstrating that the Gleason sum's predictive ability improved significantly over time. After adjusting for other variables, the Gleason sum continued to demonstrate a significantly improved predictive ability in the more recent time cohort.
  
  
  CONCLUSIONS
  We found a trend toward the assignment of increasing Gleason sums over time in our data set. This shift in Gleason sum distribution between the two time cohorts has resulted in a significant improvement in the predictive ability of the Gleason system.
authors: J. Bentley Squier Urologic Clinic, Columbia University College of Physicians and Surgeons, New York, New York 10032, USA.
authors: Robert E
authors: RE
authors: Mitchell
authors: Jay B
authors: JB
authors: Shah
authors: Manisha
authors: M
authors: Desai
authors: Mahesh M
authors: MM
authors: Mansukhani
authors: Carl A
authors: CA
authors: Olsson
authors: Mitchell C
authors: MC
authors: Benson
authors: James M
authors: JM
authors: McKiernan
mesh_terms: D018572:Disease-Free Survival; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D017430:Prostate-Specific Antigen / Q000097:blood*; D011468:Prostatectomy; D011471:Prostatic Neoplasms / Q000097:blood / Q000145:classification* / Q000401:mortality / Q000601:surgery; D015203:Reproducibility of Results
chemical_list: D017430:Prostate-Specific Antigen