Prostate atrophy (PA) and chronic prostate inflammation (CPI) in baseline biopsies, especially when these findings occur together, are associated with lower prostate cancer risk and grade, according to a new study.
A team led by Daniel M. Moreira, MD, of the University of Illinois at Chicago, retrospectively studied 6132 men aged 50 to 75 years who underwent 2-year repeat prostate biopsies after a negative baseline biopsy for prostate cancer (PCa) in the REDUCE (REduction by DUtasteride for prostate Cancer Events) trial. The investigators evaluated the association of baseline PA and CPI with 2-year repeat biopsy cancer status and grade.
PA, CPI, and both were detected in 583 (9.5%), 1063 (17.4%), and 3675 (59.9%) baseline biopsies, respectively. Compared with biopsies with neither PA nor CPI, the presence of PA, CPI, and both was associated with a significant 21%, 29%, and 36% lower odds of PCa in the 2-year repeat biopsy, respectively, in multivariable analysis, Dr Moreira and his colleagues reported online ahead of print in Prostate Cancer and Prostatic Diseases. Among patients with both PA and CPI, those with both findings in the same core had a significant 27% lower odds of PCa in multivariable analysis.
Multivariable analyses included adjustments for baseline age, race, PSA, digital rectal examination findings, body mass index, prostate volume (PV), among other potential confounders.
In addition, compared with the absence of both PA and CPI, the presence of CPI, either alone or occurring together with prostate atrophy in the same biopsy, was associated with 42% lower odds of high-grade PCa, defined as Gleason score 7–10.
Dr Moreira’s group noted that the biologic mechanisms linking prostate atrophy and chronic prostate inflammation to prostate carcinogenesis remain unclear, although a number of studies have demonstrated an association between both of these findings and larger prostate volumes. Increased prostate volumes have been correlated with a lower likelihood of PCa diagnosis in prostate biopsies. “Thus, it is plausible that PV could be a mediator between PA, CPI and PCa,” they wrote.
In the May issue of Urology (2017;103:161-166), Dr Moreira and colleagues reported findings from a separate retrospective analysis of 3165 men in the REDUCE trial showing that the extent of baseline PA is independently associated with lower PCa risk in a dose-dependent fashion. Compared with men without PA, those with 1%–25%, 26%–50%, 51%–75%, and greater than 75% core involvement had 35%, 40%, 44%, and 65% lower odds of PCa. In addition, men with PA in more cores had a lower incidence of both low-grade (Gleason 2–6) and high-grade (Gleason 7–10) PCa, they reported.
Moreira DM, Freitas DM, Nickel JC, et al. The combination of histological prostate atrophy and chronic prostate inflammation is associated with lower risk of prostate cancer in biopsy specimens. Prostate Cancer Prostatic Dis 2017; published online ahead of print.