Prognostic Significance of a Negative Prostate Biopsy: An Analysis of Subjects Enrolled in a Prostate Cancer Screening Trial.

Abstract

To our knowledge the optimal treatment of patients following a negative prostate biopsy is unknown. Consequently, resources are increasingly being directed toward risk stratification in this cohort. However, the risk of prostate cancer mortality in this group before the introduction of supplemental biomarkers and imaging techniques is unclear. The PLCO (Prostate, Lung, Colorectal and Ovarian Cancer) Screening Trial provides survival data prior to the implementation of new diagnostic interventions. We divided men with an initial positive screen and a subsequent prostate biopsy into cohorts based on positive or negative results. Prostate cancer specific mortality was then compared to that in the trial control arm to estimate the prognostic significance of biopsy results relative to the general population. A total of 36,525 and 36,560 patients comprised the screening and control arms, respectively. Of 4,064 subjects with a positive first screen 1,233 underwent a linked biopsy, of which 473 were positive and 760 were negative. At a median followup of 12.9 years, 1.1% of men in the negative biopsy cohort had died of prostate cancer. The difference in mortality rates between the negative biopsy and control arms was 0.734 deaths per 1,000 person-years. The proportional subhazard ratios of prostate cancer specific mortality for negative biopsy and positive biopsy relative to the control arm were 2.93 (95% CI 1.44-5.99) and 18.77 (95% CI 12.62-27.93), respectively. After a negative prostate biopsy, men face a relatively low risk of death from prostate cancer when followed with traditional markers and biopsy techniques. This suggests limited potential for new diagnostic interventions to improve survival in this group.