Pathologic Features of Occult Prostatic Carcinoma in Hypogonadal Men

Objectives: Androgen therapy in hypogonadal men with low free testosterone levels (< 1.5 ng/dl) is potentially dangerous because exogenous androgen may stimulate occult prostatic adenocarcinoma (PA). Our previous study reported occult PA (14% incidence) in hypogonadal men with normal prostate specific antigen (PSA) levels and normal findings on digital rectal examination (DRE). The purpose of the current study was to examine the extent and nature of PA in prostatectomy specimens of hypogonadal patients. Materials and Methods: PA in these14 patients (the hypogonadal group) was compared to a control group of patients (n = 14). The two groups of patients were matched with similar mean ages, Gleason scores, and percentage of core involvement by PA. Subsequently, PA in prostatectomy specimens was analyzed in the two groups with additional comparison of immunohistochemical sections for androgen receptors, PSA, and prostatic acid phosphatase. Results: As expected, patients in the hypogonadal group had significantly lower levels of PSA and free testosterone than those in the control group (PSA 2.32 ± 0.60 ng/ml versus 8.06 ± 1.17 ng/ml, respectively; free testosterone 1.17 ± 0.09 ng/dl versus 1.74 ± 0.20 ng/dl, respectively). Prostatectomy specimens in hypogonadal patients (n = 9) showed a less extensive PA (0% positive margins, 11% perineural invasion, 78% unilateral tumor, and 22% bilateral tumor) compared to control prostatectomy specimens (n = 14) (21% positive margins, 42% perineural invasion, 21% unilateral tumor, and 58% bilateral tumor). However, immunohistochemical studies using anti-androgen receptor, anti-PSA and anti-prostatic acid phosphatase antibodies showed that carcinoma cells stained with equivalent intensity in both groups. Conclusions: PA in hypogonadal patients who had normal DREs and PSA levels appears to be less extensive but otherwise is not morphologically different than usual and should be treated in the same manner. The high incidence of occult PA in these hypogonadal patients makes screening prostate biopsies important before the androgen replacement therapy.