Most men who receive continuous androgen deprivation therapy (hormone therapy) for prostate cancer will develop some sexual dysfunction. Typically, after a few months of hormone therapy, men will start to have a loss of libido (interest in sex), often followed by erectile dysfunction.
Because the association between hormone therapy and sexual dysfunction is well known, your doctor will likely counsel you on this risk before you start treatment. One way your doctor may be able to lessen the duration or severity of your sexual dysfunction is by using intermittent hormone therapy.
Your doctor may recommend intermittent androgen deprivation therapy rather than continuous therapy. With intermittent therapy, you undergo hormone therapy for a certain amount of time - usually several months to a year - in order to reduce the PSA level to as low as possible. Once the PSA low point has been reached, hormone therapy is stopped completely. Your doctor will then set a predetermined PSA level that, once reached, will require you to restart hormone therapy. This process can often be repeated.
During the time off from hormone therapy, the negative side effects of the drugs typically wear off, including sexual dysfunction.
It is not clear whether intermittent hormone therapy for prostate cancer results in the same rate of survival as continuous hormone therapy. It's important to discuss that and other issues with your doctor early on.
Loblaw DA, Virgo KS, Nam R, et al. Initial hormonal management of androgen-sensitive metastatic, recurrent, or progressive prostate cancer: 2006 update of an American Society of Clinical Oncology practice guideline. J Clin Oncol. 2007;25(12):1596.
Wilke DR, Parker C, Andonowski A, et al. Testosterone and erectile function recovery after radiotherapy and long-term androgen deprivation with luteinizing hormone-releasing hormone agonists. BJU Int. 2006;97(5):963.