Background: It is not yet known whether screening for the detection of early prostate carcinoma will reduce mortality rates. However, data are available to assess intermediate outcomes from screening, including the performance characteristics of the screening tests and shifts in disease stage.
Methods: Approximately 30,000 community volunteers (mean age 60 years; <5% nonwhite) were enrolled in 1 of 3 screening studies. Volunteers were screened with PSA or PSA in combination with digital rectal examination at 6-month intervals, and prostatic biopsy was recommended for those with results suspicious for cancer. Based on a first-time screen, the current study reports screening test results, the proportion of men recommended to undergo biopsy, the proportion who actually underwent biopsy, and the carcinoma detection rates for each study, stratified by initial PSA level. The authors also report the pathologic features of screen-detected carcinomas for a subset of men who underwent radical prostatectomy and for whom complete embedding and microscopic examination of the surgical specimen was performed.
Results: Approximately 10% of the volunteers had PSA levels >4.0 ng/mL and 3-10% had digital rectal examination results suspicious for cancer. Overall, 9-20% of volunteers were recommended to undergo biopsy and 8-13% actually underwent the procedure. The positive predictive value for carcinoma detection ranged from 25-33% across studies. In the subset of men for whom surgical specimens were completely embedded, the majority of tumors detected had the clinicopathologic features of significant carcinoma (<10% possibly harmless).
Conclusions: The intermediate outcomes for screening with PSA and/or PSA in combination with digital rectal examination are encouraging. In community volunteers these screening tests demonstrated reasonable positive predictive value and detected carcinomas at an earlier stage. The majority of screen-detected tumors had the pathologic characteristics of medically significant carcinoma.