Medical management has been shown to produce variable results. Reports of successful medical treatment have been most consistently linked to instances when the gynecomastia is of recent onset and is caused by testosterone deficiency. Testosterone administration has inconsistent effects in persons with Klinefelter syndrome, but it can cause dramatic improvement in those with other forms of testicular failure (eg, anorchia, viral orchitis). Testosterone therapy involves an element of uncertainty because testosterone can serve as substrate for extraglandular estrogen formation. Under some circumstances (eg, patient with liver disease), androgen therapy can cause a disproportionate increase in plasma estrogen levels.
Various drug regimens have been tried for the treatment of gynecomastia. These drugs include the antiestrogens tamoxifen7 and clomiphene, the aromatase inhibitor testolactone, and danazol (a weak androgen that inhibits gonadotropin secretion and causes a decrease in plasma testosterone). Treatment with dihydrotestosterone, which cannot be aromatized to estrogen, has also been reported to cause significant symptomatic improvement in uncontrolled studies of persons with gynecomastia. However, to the authors' knowledge, no controlled studies have been conducted to test the clinical effectiveness of any of these regimens and, in the authors’ hands, none of the aforementioned treatments have been even minimally successful in patients with idiopathic gynecomastia.
Without an increase in receptor number or binding capacity of the receptors, exogenous medical treatment is not likely to be effective; therefore, medical treatment is not likely to be effective for patients with idiopathic gynecomastia, since they do not exhibit an altered number of such receptors.
Several studies have shown that prophylactic breast irradiation reduces the risk of gynecomastia in patients with prostate cancer who are undergoing long-term estrogen or anti-androgen therapy. The risks of long-term malignancies, however, have not been clearly defined. Radiation in cases of idiopathetic gynecomastia is not indicated at this time.