title: Predictors of Gleason Score (GS) upgrading on subsequent prostatectomy: a single Institution study in a cohort of patients with GS 6.
abstract: BACKGROUND
  Biopsy Gleason score (bGS) remains an important prognostic indicator for adverse outcomes in Prostate Cancer (PCA). In the light of recent studies purporting difference in prognostic outcomes for the subgroups of GS7 group (primary Gleason pattern 4 vs. 3), upgrading of a bGS of 6 to a GS≥7 has serious implications. We sought to identify pre-operative factors associated with upgrading in a cohort of GS6 patients who underwent prostatectomy.
  
  
  METHODS
  We identified 281 cases of GS6 PCA on biopsy with subsequent prostatectomies. Using data on pre-operative variables (age, PSA, biopsy pathology parameters), logistic regression models (LRM) were developed to identify factors that could be used to predict upgrading to GS≥7 on subsequent prostatectomy. A decision tree (DT) was constructed.
  
  
  RESULTS
  92 of 281 cases (32.7%) were upgraded on subsequent prostatectomy. LRM identified a model with two variables with statistically significant ability to predict upgrading, including pre-biopsy PSA (Odds Ratio 8.66; 2.03-37.49, 95% CI) and highest percentage of cancer at any single biopsy site (Odds Ratio 1.03, 1.01-1.05, 95% CI). This two-parameter model yielded an area under curve of 0.67. The decision tree was constructed using only 3 leave nodes; with a test set classification accuracy of 70%.
  
  
  CONCLUSIONS
  A simplistic model using clinical and biopsy data is able to predict the likelihood of upgrading of GS with an acceptable level of certainty. External validation of these findings along with development of a nomogram will aid in better stratifying the cohort of low risk patients as based on the GS.
authors.affiliation: Department of Pathology, Loyola University Medical Center, Maywood, IL 60153, USA.
authors.forename: Vikas
authors.initials: V
authors.lastname: Mehta
authors.forename: Kevin
authors.initials: K
authors.lastname: Rycyna
authors.forename: Bart M M
authors.initials: BM
authors.lastname: Baesens
authors.forename: Güliz A
authors.initials: GA
authors.lastname: Barkan
authors.forename: Gladell P
authors.initials: GP
authors.lastname: Paner
authors.forename: Robert C
authors.initials: RC
authors.lastname: Flanigan
authors.forename: Eva M
authors.initials: EM
authors.lastname: Wojcik
authors.forename: Girish
authors.initials: G
authors.lastname: Venkataraman
mesh_terms: D000230:Adenocarcinoma / Q000097:blood / Q000473:pathology*; D000328:Adult; D000368:Aged; D001706:Biopsy; D015331:Cohort Studies; D003663:Decision Trees; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D009361:Neoplasm Invasiveness; D057234:Preoperative Period; D011379:Prognosis; D017430:Prostate-Specific Antigen / Q000097:blood; D011468:Prostatectomy; D019048:Prostatic Intraepithelial Neoplasia / Q000097:blood / Q000473:pathology*; D011471:Prostatic Neoplasms / Q000097:blood / Q000473:pathology*; D018570:Risk Assessment / Q000379:methods
chemical_list: D017430:Prostate-Specific Antigen