Effect of GH and/or testosterone deficiency on the prostate: an ultrasonographic and endocrine study in GH-deficient adult patients.

BACKGROUND The role of IGF-I in prostate development is currently under thorough investigation since it has been claimed that IGF-I is a positive predictor of prostate cancer. OBJECTIVE To investigate the effect of chronic GH and IGF-I deficiency alone or associated with testosterone deficiency on prostate pathophysiology in a series of patients with hypopituitarism. DESIGN Pituitary, androgen and prostate hormonal assessments and transrectal prostate ultrasonography (TRUS) were performed in 30 men with adulthood onset GH deficiency (GHD) and 30 age-matched healthy controls, free from previous or concomitant prostate disorders. RESULTS Plasma IGF-I levels were significantly lower in GHD patients than in controls (Pearson's coefficient P<0.0001). At study entry, 6 of the 13 hypogonadal patients and 7 of the 17 eugonadal patients had plasma IGF-I below the age-adjusted normal range. At study entry, testosterone levels were low in 13 patients (mean +/-s.e.m., 3.8+/-1.0 nmol/l) while they were normal in the remaining 17 (19.4+/-1.4 nmol/l). No difference in prostate-specific antigen (PSA), and PSA density was found between GHD patients (either hypo- or eugonadal) and controls, while free PSA levels were significantly higher in eugonadal GHD than in controls (0.4+/-0.04 vs 0.2+/-0.03 microg/l; P<0.01). No difference in antero-posterior prostate diameter and transitional zone volume (TZV) was observed among groups, while both transverse and cranio-caudal diameters were significantly lower in hypogonadal (P<0.01) and eugonadal GHD patients (P<0.05) than in controls. Prostate volume (PV) was significantly lower in hypogonadal GHD patients (18.2+/-3.0 ml) and eugonadal GHD patients (22.3+/-1.6 ml), than in controls (25.7+/-1.4, P<0.05). The prevalence of prostate hyperplasia (PV>30 ml) was significantly lower in hypogonadal and eugonadal GHD patients, without any difference between them (15.3% and 5.8%), than in controls (43.3%) (chi(2)=6.90, P=0.005). No difference was found in PV between patients with normal or deficient IGF-I levels both in the hypogonadal group (19. 9+/-4.7 vs 17.3+/-4.0 ml) and in the eugonadal group (22.6+/-2.3 vs 21.8+/-2.5 ml). When controls and patients were divided according to age (<60 years and >60 years), PV was significantly lower in hypogonadal GHD patients aged below 60 years than in age-matched controls (P<0.01) or eugonadal GHD patients (P<0.01), without any difference between controls and eugonadal GHD patients. Controls aged above 60 years had significantly higher PV than both hypogonadal and eugonadal GHD patients (P<0.01). Calcifications, cysts or nodules were found in 56.7% of patients and in 50% of controls (chi(2)=0.067, P=0.79). In controls, but not in GHD patients, PV and TZV were correlated with age (r=0.82, r=0.46, P<0. 0001 and P<0.01 respectively). PV was also correlated with GH (r=-0. 52, P=0.0026), IGF-I (r=-0.62, P=0.0002) and IGF-binding protein 3 (IGFBP-3) levels (r=-0.39, P=0.032) but neither with testosterone or dihydrotestosterone (DHT) levels. In GHD patients TZV but not PV was correlated with age (r=0.58, P=0.0007) and neither TZV nor PV were correlated with GH, IGF-I or IGFBP-3 levels. CONCLUSIONS Chronic GH deficiency in adulthood causes a decrease in prostate size, mostly in patients with concomitant androgen deficiency and age below 60 years, without significant changes in the prevalence of structural prostate abnormalities.