Prostate cancer in patients with an abnormal digital rectal examination and serum prostate-specific antigen less than 4.0 ng/mL

Objectives. To evaluate men with abnormal digital rectal examination (DRE) findings and a serum prostate-specific antigen (PSA) level less than 4.0 ng/mL who underwent prostate biopsy. Methods. A total of 986 patients undergoing prostate biopsy were documented to have DRE findings suspicious for prostate cancer and a serum PSA level of less than 4.0 ng/mL. We examined the serum PSA level, age, and race to see which patient characteristics were statistically significant predictors of prostate cancer on biopsy. The pathologic findings of the biopsy and prostatectomy specimens were examined to determine which patients had serendipitously diagnosed prostate cancer. Results. The positive predictive value of an abnormal DRE was 8.8%. The PSA level and increasing age were statistically significant predictors of a positive biopsy, but race was not. Well-differentiated cancer (Gleason score 6 or less) was diagnosed in 72.8% of the biopsies. Also, 87.5% of the patients undergoing radical prostatectomy had pathologic Stage T2 disease. Using specific pathologic criteria, prostate cancer was diagnosed serendipitously in 19% of the biopsies and in 43% of the radical prostatectomy specimens. Conclusions. Higher serum PSA levels even if less than 4.0 ng/mL were associated with dramatic increases in prostate cancer detection. Age was also a statistically significant predictor of cancer. Although the overall positive predictive value of the DRE was poor, most patients diagnosed with prostate cancer had an abnormality on the DRE that corresponded either to the location of cancer detected on biopsy or had cancer volumes on prostatectomy specimens large enough to be palpable.