Effect of Two Years of Growth Hormone and Insulin-Like Growth Factor-I Suppression on Prostate Diseases in Acromegalic Patients1

The insulin-like growth factors (IGFs) have mitogenic effects on normal and tumoral prostate epithelial cells and have been suggested to be involved in prostate cancer. Moreover, chronic GH and IGF-I excess causes prostate overgrowth in patients with acromegaly. This study was designed to investigate whether the suppression of GH and IGF-I levels by surgery or pharmacotherapy could induce the regression of prostatic hyperplasia in acromegalic patients. To this end, prostate volume (PV) as well as the occurrence of prostatic diseases were studied by transrectal ultrasonography in 23 untreated acromegalic patients (with elevated GH and IGF levels). None of the patients reported symptoms due to prostatic disorders or obstruction. At study entry, prostate hyperplasia was found in half patients. After 2 yr, GH, IGF-I, and IGFBP-3 levels were decreased, whereas prostate-specific antigen levels did not change. PV was decreased in the 16 patients who were well controlled. Among the 6 patients with prostate hyperplasia at study entry who achieved disease control, 4 regained a normal PV at the end of the 2 yr of treatment, whereas none of the 5 patients with prostate hyperplasia at study entry and not achieving disease control normalized their PV. When patients were divided according to age, prostate volume decreased after 2 yr only in the 8 controlled patients aged below 50 yr, but not in those controlled and with age above 50 yr despite similar decrease in GH, IGF-I, and IGFBP3 levels. No clinical, transrectal ultrasonography, or cytological evidence of prostate cancer was detected during the study period. These data suggest that hyperplasia, but not cancer, is frequent in acromegalic men, and that the GH-IGF axis and age are independently associated with the development of this process.