title: Gleason Score ≤ 6 Prostate Cancer at Radical Prostatectomy: Does a High-Risk Setting Truly Exist? A Recursive Partitioning Analysis.
abstract: The purpose of this study was to determine whether a "high-risk" subpopulation of low-grade (Gleason score ≤6) prostate cancer defined by lower prostate-specific antigen (PSA) relapse-free survival (bRFS) might be identified within a large population of men who underwent radical prostatectomy (RP) alone, with mature follow-up.
  
  
  
  Patients were retrospectively identified for inclusion by cT1-2 prostate cancer managed with RP alone. Exclusion criteria were: Gleason score ≥7 at RP, any pre- or post-RP radiotherapy or hormone therapy, or PSA follow-up <12 months. The Kaplan-Meier method was used for survival estimates; recursive partitioning by conditional inference analysis was applied to identify variables associated with bRFS.
  
  
  
  From 2002 through 2010, 284 eligible patients were identified. Median age was 60 years (range, 44-76 years), 233 (82%) were cT1c, and median PSA was 5.3 ng/dL (92% ≤10). The median biopsy to RP interval was 50 days (range, 11-410, with 97% <180 days). Eighty patients (28%) had positive margin (M+). At a median follow-up of 92.6 months (range, 16.9-160.9, with 45% followed ≥ 8 years), 32 patients (11%) had PSA failure, with an estimated 8-year bRFS rate of 89%. In univariate analysis, M+, extraprostatic extension, detectable initial post-RP PSA, and longer biopsy to RP interval were significantly associated with lower bRFS. M+ and longer biopsy to RP interval remained significant in multivariable analysis. Recursive partitioning analysis identified M+ as the only stratification factor, with 8-year bRFS estimates of 74% versus 95% for M+ versus margin-negative.
  
  
  
  Gleason score ≤6 prostate cancer managed using RP alone is associated with high rates of bRFS; however, margin positivity predicts early PSA failure rates in >20% of patients.
authors.affiliation: Department of Radiation Oncology, University of Iowa, Carver School of Medicine, Iowa City, IA. Electronic address: john.m.watkins.md@hotmail.com.
authors.forename: John M
authors.initials: JM
authors.lastname: Watkins
authors.affiliation: Department of Radiation Oncology, University of Iowa, Carver School of Medicine, Iowa City, IA.
authors.forename: Darrion L
authors.initials: DL
authors.lastname: Mitchell
authors.affiliation: Bismarck Cancer Center, Bismarck, ND.
authors.forename: J Kyle
authors.initials: JK
authors.lastname: Russo
authors.affiliation: Holden Comprehensive Cancer Center, Iowa City, IA.
authors.forename: Sarah L
authors.initials: SL
authors.lastname: Mott
authors.affiliation: Department of Urology, University of Iowa, Carver School of Medicine, Iowa City, IA.
authors.forename: Chad R
authors.initials: CR
authors.lastname: Tracy
authors.affiliation: Department of Radiation Oncology, University of Iowa, Carver School of Medicine, Iowa City, IA.
authors.forename: Mark C
authors.initials: MC
authors.lastname: Smith
authors.affiliation: Department of Radiation Oncology, University of Iowa, Carver School of Medicine, Iowa City, IA.
authors.forename: John M
authors.initials: JM
authors.lastname: Buatti
mesh_terms: D000368:Aged; D006801:Humans; D007610:Kallikreins / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D017430:Prostate-Specific Antigen / Q000378:metabolism; D011468:Prostatectomy / Q000379:methods*; D011471:Prostatic Neoplasms / Q000378:metabolism / Q000473:pathology* / Q000601:surgery*; D016019:Survival Analysis; D016896:Treatment Outcome
chemical_list: C549870:KLK3 protein, human; D007610:Kallikreins; D017430:Prostate-Specific Antigen
keywords: Gleason score; Pathology; Radical prostatectomy; Radiotherapy; Surgical margins