Prostatic asymmetry as a risk factor for prostatic carcinoma: serial prostate-specific antigen monitoring and cancer detection

To compare the rates of cancer detection in men with a normal, asymmetric, or suspicious prostate on digital rectal examination (DRE) initially and after 3 years of serial monitoring of prostate specific antigen (PSA) level.

Prostatic 'asymmetry' was defined as asymmetric growth of the lateral lobes of the prostate without induration or nodules, as assessed by a DRE. The study included 963 men with no clinical evidence of prostate cancer and whose serum PSA levels were monitored at 4 month intervals. Prostatic biopsy was recommended if the PSA level became persistently abnormal (> 4ng/mL) or increased by > 20% after having been initially abnormal. Cancer detection rates were compared among groups categorized by the initial DRE findings and serum PSA level.

On comparing groups with suspicious and normal DREs, and abnormal with normal PSA levels both, as expected, were associated with a statistically significant increase in cancer detection. However, an asymmetric prostate did not carry an increased risk of detecting prostate cancer when compared with a normal prostate, regardless of PSA level.

An asymmetric prostate does not appear to be an independent risk factor for detecting prostate cancer. Therefore, an asymmetric prostate with no abnormality in PSA level should not mandate prostatic biopsy, or even an increase in monitoring frequency above the presently recommended annual interval.