Sexual orientation and impact of androgen deprivation therapy

An article by a group of Romanian researchers published in October this year may have some controversial implications — so we want to be very clear that we don’t think too much should be read into it unless their data can be replicated by others.

Motofei et al. compared the effects of a standard dose of bicalutamide (50 mg once daily) on a series of 29 men with locally advanced but non-metastatic prostate cancer. The primary objective of the research was to investigate the impact of treatment on sexual arousal and sexual response among this group of men (given that bicalutamide monotherapy has less impact on sexual function than LHRH agonist treatment).

What is important in this research, however, is that 17/29 patients self-identified as heterosexual and 12/29 as homosexual. All patients were asked about their sexual function immedately prior to bicalutamide treatment, then again about 5 weeks later, after starting bicalutamide, and then a third time after 4-6 months on treatment. All reported data were based on responses to the International Index of Erectile Function (IIEF) questionnaire.

Neither the abstract of the original paper, nor the editorial comment on this paper on the UroToday web site provide much actual data, and we have not seen the full text of this paper. However, here are the core results:

  • IIEF scores prior to bicalutamide therapy showed no difference based on sexual orientation.
  • There was a significant overall “group orientation” effect in response to bicalutamide therapy
  • Homosexual men had lower IIEF scores than heterosexual men while receiving bicalutamide.
  • Homosexual men had a greater decrease in IIEF scores than heterosexual men over time.
  • Homosexual men showed lower functioning than heterosexual men in response to bicalutamide based on data from such subscales as erectile function, orgasmic function, sexual desire, and overall satisfaction.

One can conclude from this study that some effects of antiandrogen therapy seem to differ for heterosexual and homosexual men and that the activational effects of androgens on sexual motivation, arousal, and behavior may also differ between heterosexual and homosexual males. However, this is a small study; the authors are careful to describe it as “preliminary;” and the authors themselves are very limited in their conclusions.

We really have very little information on the impact of male (gonadal) hormone levels on sexual arousal, libido and sexual orientation. Some researchers may see this study as hypothesis-generating. However, The “New” Prostate Cancer InfoLink thinks it might be of greatest value to repeat this study in a larger, comparable group of patients before over-interpreting this small set of preliminary data.

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