Objective: Testosterone (T) substitution of hypogonadal men by conventional intramuscular injection of T esters is not considered optimal because it induces unphysiologically fluctuating serum T levels. In contrast, scrotal T patches produce normal serum (T) levels mimicking diurnal variations. In order to assess the quality of this new form of T substitution we followed hypogonadal men treated by transdermal T up to 10 years.
Patients: Eleven men aged 35.9 +/- 9.8 years (mean +/- SD) at the beginning of the study were treated with transscrotal T patches (Testoderm) because of primary (n = 4) or secondary (n = 7) hypogonadism. Clinical examinations were performed every 3 months during the first 5 years and every 6 months thereafter. All 11 patients were seen for 7 years and some for longer periods: eight for 8 years, six for 9 years and four for 10 years.
Measurements and results: With daily application of one patch T levels rose from 5.3 +/- 1.3 nmol/l (mean +/- SE) to 16.7 +/- 2.6 nmol/l at month 3 and remained in the normal range throughout treatment. Serum 5 alpha-dihydrotestosterone (DHT) rose from 1.3 +/- 0.4 nmol/l to 3.9 +/- 1.4 nmol/l and oestradiol from 52.3 +/- 9.3 to 71.3 +/- 9.6 pmol/l and remained stable without significant variations throughout the observation period. Patients reported absence of local side-effects except for occasional itching. No relevant changes occurred in clinical chemistry, including total cholesterol levels and triglycerides. Haemoglobin and erythrocyte counts remained normal. Bone density measured by QCT increased slightly from 113.6 +/- 5.4 to 129.7 +/- 9.3 mg/cm3 during the observation period (P = 0.028). In the nine patients aged < 50 years prostate volumes showed a small but insignificant increase from 16.8 +/- 1.5 to 18.8 +/- 2.1 ml during transscrotal T therapy. In the two older patients prostate volume remained constant or decreased slightly during T therapy after an initial increase in the previously untreated patient. Prostate specific antigen levels were constantly low in all patients.
Conclusion: Transscrotal testosterone patches are well-accepted and safe in long-term testosterone substitution therapy for male hypogonadism.