High prevalence of hypogonadism determined by serum free testosterone level in Japanese testicular cancer survivors

OBJECTIVE: Hypogonadism is a major complication in testicular cancer survivors, but its prevalence varies among studies. In Japan, free testosterone has been used for diagnosis of late-onset hypogonadism syndrome. In the present study, we evaluated the hormone level of testicular cancer survivors and its impact on their quality of life. METHODS: Overall, 50 testicular cancer survivors treated from 1990 to 2013 were enrolled. The median age was 44 years. The serum levels of free testosterone, total testosterone and luteinizing hormone were measured. All patients completed the Aging Males' Symptom scale and International Index of Erectile Function-15. The hormone levels of 337 healthy volunteers were used as the control. RESULTS: A total of 32 (64%) patients showed free testosterone levels <8.5 pg/mL. In contrast, just 26% of 50 patients showed total testosterone levels <3.5 ng/mL. Testicular cancer survivors had significantly lower free testosterone and higher luteinizing hormone compared with healthy controls. In contrast, there was no difference in total testosterone between patients and controls. The prevalence of late-onset hypogonadism symptoms of any grade (Aging Males' Symptom total score ≥27) was 60%. Overall, 64% were defined as having moderate erectile dysfunction (International Index of Erectile Function-Erectile Function domain score <17). However, Aging Males' Symptom, International Index of Erectile Function-15 and Erectile Function domain scores did not differ by free testosterone or total testosterone level. CONCLUSIONS: This is the first report on the prevalence of hypogonadism determined by free testosterone level in Japanese testicular cancer survivors. Because Aging Males' Symptom and International Index of Erectile Function-15 scores do not necessarily reflect the hormone level, measuring free testosterone is also important in the follow up of these patients.