Baseline prostate atrophy is associated with reduced risk of prostate cancer in men undergoing repeat prostate biopsy.

INTRODUCTION - We evaluated whether presence and severity of baseline prostate atrophy among men with initial negative biopsy for prostate cancer (PCa) was associated the risk of subsequent PCa detection in a clinical trial with scheduled study-mandated biopsies.

METHODS - Retrospective analysis of 3084 men 50-75 years-old with prostate-specific antigen between 2.5-10ng/mL and a prior negative biopsy from the placebo arm of the Reduction by Dutasteride of PCa Events study who completed at least one per-protocol biopsy. PCa (defined as present or absent) and prostate atrophy (graded as absent, mild or moderate/marked) were assessed by central pathology review. The association of baseline atrophy with positive 2- and 4-year repeat biopsies was evaluated with logistic regression controlling for baseline covariates.

RESULTS - Baseline prostate atrophy was detected in 2143 (70%) and graded as mild, moderate/marked in 1843 (60%) and 300 (10%) baseline biopsies, respectively. Patients with atrophy were older and had larger prostates and more acute and chronic prostate inflammation. At 2-year biopsy, PCa incidence was 17% (N=508). Baseline atrophy was significantly associated with lower PCa risk (multivariable OR=0.60, 95%CI=0.50-0.74 and OR=0.67, 95%CI=0.54-0.83, P<0.001, respectively) at the 2-year biopsy. These results were similar at the 4-year biopsy (OR=0.70, 95%CI=0.53-0.93; OR=0.72, 95%CI=0.53-0.97, P=0.03, respectively uni- and multivariable). Relative to no atrophy, PCa risk at the 2-year repeat biopsy was lower for both mild (OR=0.69, 95%CI=0.55-0.86, P<0.001) and moderate/marked atrophy (OR=0.51, 95%CI=0.34-0.76, P<0.001).

CONCLUSIONS - Baseline prostate atrophy among men with a negative prostate biopsy for PCa was independently associated with subsequent lower PCa detection.

J Urol. 2015 Jul 9. pii: S0022-5347(15)04325-6. doi: 10.1016/j.juro.2015.05.103. [Epub ahead of print]

Moreira DM1, Bostwick DG2, Andriole GL3, Peterson BL4, Cohen HJ5, Castro-Santamaria R6, Freedland SJ7.

1 Department of Urology, Mayo Clinic, Rochester, MN.
2 Bostwick Laboratories, Inc.
3 Division of Urologic Surgery, Department of Surgery, Washington University School of Medicine, St. Louis, MO, USA.
4 Department of Biostatistics and Bioinformatics, Duke University School of Medicine, Durham, NC, USA.
5 Department of Medicine, Duke University School of Medicine, Durham, NC, USA.
6 GlaxoSmithKline Inc., Global R&D Unit, King of Prussia, Pennsylvania, PA, USA.
7 Division of Urology, Department of Surgery, Cedars Sinai Medical Center, Los Angeles, CA, USA; Urology Section, Veterans Affairs Medical Center, Durham, NC, USA.