OBJECTIVE: To modify the Prostate Cancer Prevention Trial risk calculator (PCPTRC) to predict low- vs high-grade (Gleason grade ≥7) prostate cancer and incorporate percent free-prostate-specific antigen (PSA).
METHODS: Data from 6664 Prostate Cancer Prevention Trial placebo arm biopsies (5826 individuals), where prostate-specific antigen and digital rectal examination results were available within 1 year before the biopsy and PSA was ≤ 10 ng/mL, were used to develop a nominal logistic regression model to predict the risk of no vs low-grade (Gleason grade < 7) vs high-grade cancer (Gleason grade ≥7). Percent free-PSA was incorporated into the model based on likelihood ratio analysis of a San Antonio Biomarkers of Risk cohort. Models were externally validated on 10 Prostate Biopsy Collaborative Group cohorts and 1 Early Detection Research Network reference set.
RESULTS: Of all the Prostate Cancer Prevention Trial biopsies, 5468 (82.1%) were negative for prostate cancer, 942 (14.1%) detected low-grade, and 254 (3.8%) detected high-grade disease. Significant predictors were (log base 2) PSA (odds ratio for low-grade vs no cancer, 1.29*; high-grade vs no cancer, 2.02*; high-grade vs low-grade cancer, 1.57*), digital rectal examination (0.96, 1.49*, 1.55*, respectively), age (1.02*, 1.05*, 1.03*, respectively), African American race (1.13, 2.83*, 2.51*, respectively), prior biopsy (0.63*, 0.81, 1.27, respectively), and family history (1.31*, 1.25, 0.95, respectively), where * indicates P value < .05. The new PCPTRC 2.0 either with or without percent free-PSA (also significant by the likelihood ratio method) validated well externally.
CONCLUSION: By differentiating the risk of low- vs high-grade disease on biopsy, PCPTRC 2.0 better enables physician-patient counseling concerning whether to proceed to biopsy.
Written by:
Ankerst DP, Hoefler J, Bock S, Goodman PJ, Vickers A, Hernandez J, Sokoll LJ, Sanda MG, Wei JT, Leach RJ, Thompson IM. Are you the author?
Department of Urology, University of Texas Health Science Center at San Antonio, San Antonio, TX; Department of Epidemiology and Biostatistics, University of Texas Health Science Center at San Antonio, San Antonio, TX; Department of Mathematics, Technical University Munich, Garching, Germany; Department of Mathematics, Technical University Munich, Garching, Germany; Department of Cellular and Structural Biology, University of Texas Health Science Center at San Antonio, San Antonio, TX; Department of Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA; Department of Epidemiology and Biostatistics, Memorial Sloan Kettering Cancer Center, New York, NY; Department of Oncology, Johns Hopkins Medical Institutions, Baltimore, MD; Department of Urology, Emory University School of Medicine, Atlanta, GA; Department of Urology, University of Michigan School of Medicine, Ann Arbor, MI; Department of Cellular and Structural Biology, University of Texas Health Science Center at San Antonio, San Antonio, TX.
Reference: Urology. 2014 Jun;83(6):1362-8.
doi: 10.1016/j.urology.2014.02.035
PubMed Abstract
PMID: 24862395
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