Age, prostate-specific antigen, and digital rectal examination as determinants of the probability of having prostate cancer

Objectives, The decision to perform prostate biopsy has traditionally been based on an abnormal prostate-specific antigen (PSA) level or abnormal digi tal rectal examination (DRE) findings. For example, a 60-year-old man with a benign DRE and PSA level of 4.1 ng/mL would be counseled for biopsy, and the same man with a PSA level of 3.9 ng/mL might be counseled against biops y. However, the difference in these PSA levels and in the likelihood of the se two men having prostate cancer is not significant. We constructed a prob ability nomogram for the likelihood of detecting prostate cancer, thus aidi ng in the decision of whether to perform a prostate biopsy. Methods. Using multivariate logistic regression analysis and data from 2054 men (mean age 64 years) participating in the Tyrol Screening Project betwe en January 9, 1993 and January 9, 1997, patient age, PSA level, and DRE fin dings were analyzed for their ability to determine the likelihood of findin g prostate cancer on transrectal ultrasound-guided biopsy. Results. DRE was suspicious in 278 men (13.5%). Overall, 498 (24.5%) of 205 4 men biopsied had prostate cancer. The probability of discovering cancer o n biopsy was calculated using patient age, DRE findings, and PSA level. Conclusions. DRE status had a large influence on the likelihood of positive biopsy across all PSA and age ranges. A combination of PSA, DRE result, an d age better defined the probability of a positive biopsy than any factor a lone. Using this nomogram, the decision to proceed with or defer prostate b iopsy can be based on an actual probability of discovering prostate cancer rather than a single PSA-based cutpoint, These data may aid physicians and patients in decision-making. UROLOGY 57: 1100-1104, 2001. (C) 2001, Elsevie r Science Inc.