Is low serum free testosterone a marker for high grade prostate cancer?

The association of free and total testosterone with prostate cancer is incompletely understood. We investigated the relationship of serum free and total testosterone to the clinical and pathological characteristics of prostate cancer.

We retrospectively reviewed the clinical records of 117 consecutive patients treated by 1 physician and diagnosed with prostate cancer at our medical center between 1994 and 1997. Low free and total testosterone levels were defined as 1.5 or less and 300 ng./dl., respectively.

After evaluating all 117 patients we noted no correlation of free and total testosterone with prostate specific antigen, patient age, prostatic volume, percent of positive biopsies, biopsy Gleason score or clinical stage. However, in patients with low versus normal free testosterone there were an increased mean percent of biopsies that showed cancer (43% versus 22%, p = 0.013) and an increased incidence of a biopsy Gleason score of 8 or greater (7 of 64 versus 0 of 48, p = 0.025). Of the 117 patients 57 underwent radical retropubic prostatectomy. In those with low versus normal free testosterone an increased mean percent of biopsies demonstrated cancer (47% versus 28%, p = 0.018). Pathological evaluation revealed stage pT2ab, pT2c, pT3 and pT4 disease, respectively, in 31%, 64%, 8% and 0% of patients with low and in 40%, 40.6%, 12.5% and 6.2% in those with normal free testosterone (p>0.05).

In our study patients with prostate cancer and low free testosterone had more extensive disease. In addition, all men with a biopsy Gleason score of 8 or greater had low serum free testosterone. This finding suggests that low serum free testosterone may be a marker for more aggressive disease.