Objective: To determine the effects of intramuscular injections with testosterone (Sustanon) on sex-hormone levels, sexual functioning and general well-being in patients treated with orchidectomy for bilateral testicular cancer.
Patients and methods: The study comprised seven men (median age 38 years, range 25-46) who had undergone orchidectomy for bilateral testicular cancer. Patients received intramuscular injections with testosterone every 3 weeks and blood samples for hormone analysis were collected from each patient at three times: one day after testosterone injection (t1), halfway between subsequent injections (t2) and just before injection (t3). Plasma hormone levels were then related to sexual function, as assessed by self-reported data on sexuality and general well-being, measurements of nocturnal penile tumescence and rigidity (NPTR) and erectile function elicited by visual erotic stimulation (VES), determined at t1, t2 and t3.
Results: During the 3-week interval between injections, there was a sixfold decrease in plasma testosterone level (mean testosterone 35.8, SD 7.8, and 6.0, SD 2.5 nmol/L, at t1 and t3, respectively). At t1, five of the men had a plasma testosterone level above the upper normal limit (> 35 nmol/L) and at t2 and t3, testosterone levels were below the reference range (< 10 nmol/L) in three and six men, respectively. Oestradiol (E2) levels showed the same pattern: at t1 the mean (SD) E2 level was 0.17 (0.07) nmol/L and at t3 0.07 (0.01) nmol/L. In contrast to follicle-stimulating hormone, luteinizing hormone (LH) mirrored the decline in plasma testosterone after injection, with the lowest levels at t1 and the highest at t3. Other hormone levels remained unchanged. Three patients reported loss of libido, decreased arousal, erectile dysfunction, fatigue and mood depression. However, neither the arousal nor the erectile problems could be verified by VES. There was no relationship between plasma testosterone levels, the reported sexual dysfunctions and the results of NPTR and VES measurements. Although unrelated to a specific testosterone level, three patients reported increased irritability, excessive sweating, hot flushes and heat intolerance at the end of the injection interval. These adverse effects of declining plasma testosterone were related to loss of libido and other sexual problems.
Conclusion: In most patients castrated for bilateral testicular cancer and receiving intramuscular injections with testosterone, plasma testosterone levels were outside the normal range. After injection, there was a rapid decline of plasma testosterone to levels below the lower normal limit. With the exception of oestradiol, sex-hormone levels were not correlated to testosterone levels. Sexual functioning was not affected by the fluctuations of plasma testosterone level. However, at the end of the injection interval, adverse psychological and physical effects had a significant impact on libido and arousal.