Prostate Cancer in Gay, Bisexual, and Other Men Who Have Sex with Men: A Review

Abstract

Purpose: Prostate cancer in gay, bisexual, and other men who have sex with men (GBM) is an emerging medical and public health concern. The purpose of this review is to summarize the literature on prostate cancer in GBM, including its epidemiology, clinical studies, and anecdotal reports.

Methods: In 2015, we undertook a structured literature review of all studies from 2000 to 2015.

Results: Despite prostate cancer being the most common cancer in GBM, the main finding of this review is that prostate cancer in GBM is very under-researched. With only 30 published articles in English (a rate of 1.9 articles per year), most of the literature is limited to case studies or anecdotal reports. There is some evidence of a link between human immunodeficiency virus (HIV)-positive status and prostate cancer, with early studies showing HIV infection as a risk factor and more recent studies as it being protective. Antiretroviral treatment appears protective. Globally, only four quantitative studies have been published. Based on this admittedly limited literature, GBM appear to be screened for prostate cancer less than other men and are diagnosed with prostate cancer at about the same rate, but have poorer sexual function and quality-of-life outcomes.

Conclusion: Methodological challenges to advancing research include challenges in subject identification, recruitment, heterocentric definitions of dysfunction based on vaginal intercourse and penetrative sex, and inappropriate measures. Six future directions, to advance the study of the effects of prostate cancer in GBM and to improve treatment, are detailed.

Introduction

Improving the health of lesbian, gay, bisexual, and transgender (LGBT) individuals is a Healthy People 2020 goal. However, the Institute of Medicine (IOM)¹ report on LGBT health highlighted the lack of information currently available about the health of LGBT populations.² Data on sexual orientation are not typically part of cancer surveillance, resulting in scarce information about cancer in sexual minorities.³ Gay, bisexual, and other men who have sex with men (GBM) who have been diagnosed with prostate cancer may have differential health-related quality of life and sexual health outcomes than heterosexual men with prostate cancer, but existing information is almost always based on small studies, clinical case studies, or an anecdote.^4,5 Until recently, there have been insufficient data on this topic, especially postcancer diagnosis, in part because, “research on the relational context of cancer and sexuality has tended to be heteronormative, assuming that men are in long-term, monogamous heterosexual relationships, thus excluding the experiences of single and gay men.”⁶

Methods

Search strategy and selection criteria

In 2015, we conducted a search using Google Scholar, with the search terms “prostate cancer,” plus terms for the target population GBM. In addition, we supplemented the search with any additional articles referenced in the articles found, with a search on “prostate cancer” and “HIV” to address this literature and because of our team's interest in treatment, on “prostate cancer” and “sexual rehabilitation.”

We searched PubMed, MEDLINE^® through Ovid, Scopus, Web of Science, Academic Search Complete, PsycINFO, Cochrane Library, EMBASE, and Science Citation Index for peer-reviewed reports published in the English language from January 1, 2000 to September 1, 2015. The search terms/statements used were “prostatic neoplasms” or “prostate cancer” or “cancer of the prostate” or “prostatic carcinoma” AND “male homosexuality” or “gay men” or “bisexual men” or “men who have sex with men” or “bisexuality.”

Inclusion and exclusion criteria

Our search on “prostatic neoplasm” yielded more than 100,000 peer-reviewed publications. On execution of the sexuality search terms, we had 30 articles. We limited our search to GBM, publications in English language, in the past 15 years, that examined the sexuality and health disparities experienced by GBM after prostate cancer diagnosis and/or treatment. We excluded studies whose primary focus was on heterosexual men that provided either no or limited assessment of homosexual men and studies that equitably included other comorbidities in their analyses (including other malignancies). We also excluded studies whose primary focus involved prostate cancer in men who have sex with men (MSM) and human immunodeficiency virus (HIV) infections, mainly because of the conflicting data on the association between prostate cancer and HIV infection (see Results section). Finally, we excluded studies of prostate cancer in transgender women (male to female individuals). Although an important population, because of the cross-sex hormonal therapy that raises important questions on the hormonal influence on prostate cancer risk, their risk likely differs from GBM.⁷

Results

The literature on prostate cancer in GBM is sparse. The literature search on publications in English since 2000 yielded 28 articles^3–5,8–32 (a conference abstract³³ was also published as a full article⁴) and 2 others^34,35 were identified through searching reference lists, for a total of 30 published articles, a rate of 1.9 articles per year. Most are case studies (n's of 1–3 GBM),^{13,19,20,22,24,29,31,32,34,35} commentaries,^{5,14,21,23,30} or practitioner's observations.^17,20,28 With 14 of the publications undertaken for a special issue in one journal,³⁶ the editors conclude, “If prostate cancer, in general, is off most people's radar screen, then gay men with prostate cancer are a truly invisible species.”²¹ We could find no quantitative studies of GBM before 2000 and only four published since then.^4,10,15,18 To review this literature, first, we summarize the epidemiological research, then quantitative studies, and then the insights from qualitative investigations, commentaries, and single case reports.

The epidemiology of prostate cancer in GBM

Prostate cancer is the second most common cancer among men in the United States, with 2,795,592 US men living with prostate cancer in 2012.³⁷ Approximately 14.0% of men will be diagnosed with prostate cancer at some point of their lifetime. Prostate cancer represents 26% of all new cancer diagnoses in men,³⁸ has the highest incidence of any cancer in men (aside from nonmelanoma skin cancer), and is the second leading cause of death from cancer in men (after lung cancer).³⁹ With an estimated 220,800 new cases in 2015,³⁷ it has a similar incidence to breast cancer in women.⁴⁰ Leading risk factors are age (average age at diagnosis is 66 years)⁴¹ and a familial history of prostate cancer.³⁷ Racial and ethnic disparities are also evident. African American (214.5/100,000) and White (130.4) men have elevated rates of diagnosis compared to Asian-Pacific Islanders (74.0) and Native American (67.1) men, whereas non-Hispanic men have higher rates (141.5) than Hispanic men (114.7).³⁷ The Centers for Disease Control and Prevention (CDC) estimate 3.5%–4.4% of US men have had sex with a man in the last 5 years,⁴² of whom 40%–60% are in sexual relationships.^43,44 By extrapolation, between 97,845 and 123,006 GBM are living with a diagnosis of prostate cancer, including 39,138–73,804 men in male couples.ⁱ One-in-six GBM and one-in-three male couples will receive a diagnosis in their lifetime, making prostate cancer the most common cancer in GBM and male couples.

Researchers have questioned whether testing rates differ for GBM from other men. Case and media reports identify homophobia as an additional barrier to digital rectal examinations as part of prostate cancer screening.^45,46 In a study of 19,410 men in the California Health Interview Survey, GBM had lower odds of having an up-to-date prostate specific-antigen test than heterosexual men (odds ratio [OR] = 0.61; 95% confidence interval [CI] = 0.42–0.89) with bivariate analyses showing African American GBM having lower rates than either heterosexual African American men or white GBM.¹²

Are GBM at disproportionate risk for prostate cancer than other men? Only three epidemiologic studies appear to inform this question and their conclusions differ. A Minnesota-based study from the late 1980s compared 250 incident cases of prostatic cancer with 238 hospital controls matched on age and race.⁴⁷ They found cases to be more likely to have a history of sexually transmitted infections (STIs) and to report homosexual partners.⁴⁷ In Washington, prostate cancer cases (n = 753) were identified from the Seattle-Puget Sound Surveillance, Epidemiology, and End Results (SEER) cancer registry 1993–1996 and compared to controls matched on gender and age.⁴⁸ Risk estimates increased directly with lifetime numbers of female (P < 0.001) but not male (P = 0.62) partners. A history of gonorrhea also elevated risk (OR = 1.50; 95% CI = 1.0–2.2). The study found no evidence that sexual orientation identity, anal sex, or a history of male partners was associated with increased risk. In contrast, a Montreal-based study compared 1590 prostate cancer cases (including 78 GBM) with 1618 population controls (with 63 GBM). Men with 20+ lifetime sexual partners and 20+ female partners were at a lower risk of prostate cancer, while 20+ lifetime male partners was associated with a slight excess risk. A history of STIs and sexual orientation identity was not significantly associated with risk.⁴⁹

Santillo has identified six gay “lifestyle cofactors” that potentially could increase the risk of prostate cancer in GBM: use of testosterone supplements and anabolic steroids, use of finasteride (Propecia) for hair loss, HIV status and antiretroviral (ARV) treatment, a fatty diet, the effects of anal sex on prostate-specific antigen (PSA) testing, and poor doctor–patient communication.²³ Since GBM are disproportionately at risk for HIV and other STIs, comparative studies of prostate cancer incidence by orientation should control for HIV/STI history.⁵⁰

The data on the association between HIV infection and prostate cancer are conflicting⁷ with earlier studies showing an increase in risk among HIV-positive relative to HIV-negative men,^51,52 while others show no difference or, more recently in the era of ARV treatment, an inverse association.^53–55 A recent cohort study of men with clinical AIDS found no difference in prostate cancer incidence as in the general population during the pre-PSA (and pre-ARV) time period (<1992), but a significant twofold reduction in risk during the PSA era (1992–2007).⁵⁵

Why HIV-positive men would be at less risk for prostate cancer warrants investigation. A study investigating disparities in prostate cancer treatment between 43 HIV-positive and 86 HIV-negative men in Chicago, Illinois, found HIV-positive men were as likely to receive treatment, less likely to undergo a radical prostatectomy, and more likely to be overtreated.⁵⁶ While the epidemiology of HIV would suggest the majority of the HIV-positive men were GBM, no data on sexual orientation were included.

In a retrospective analysis of 4498 HIV-infected US military beneficiaries, 10% of persons infected with HIV developed cancer (including 8 with prostate cancer).⁵⁷ The authors conclude that while the rate of AIDS-defining cancers continues to fall, the rate of non-AIDS defining cancers (such as prostate cancer) is rising in this population. While HIV and immunodeficiency may alter the risk of prostate cancer,^23,50,58,59 and cancer virulence,²³ ARV treatment appears protective.⁵⁷

Quantitative studies

We could find only four published studies^4,10,15,18 and one unpublished quantitative study of prostate cancer in GBM. A study in Romania tested the antiandrogen bicalutamide, a fast acting nonsteroidal antiandrogen. GBM (n = 12) had significantly worse sexual functioning following prostate cancer treatment than heterosexual men (n = 17).¹⁸ A second study of 15 GBM found MSM to have worse scores on urinary and bowel domains, ejaculatory function, and sexual bother than published norms.¹⁵

The third study was an online survey study of 92 gay men treated with prostate cancer, living in the United States and Canada. Consistent with the hypothesis that GBM may be less likely to choose radical prostatectomy, only 55% had prostatectomies (27% choosing external radiation, 25% hormone therapy, 8% brachytherapy, 9% active surveillance, and 7% other).^4,33 GBM reported significantly worse sexual functioning, urinary and bowel outcomes, more sexual bother, and poorer mental health quality-of-life posttreatment than published norms.^4,33 In addition, they had greater fear of recurrence and less satisfaction with their medical providers than other published prostate cancer samples.⁴ The relationship between physical symptoms (bowel hormonal and sexual function) and fear of recurrence was mediated by self-efficacy and satisfaction with healthcare.²⁶ Substantial differences in sexual functioning, pre- and posttreatment, were found. Among the men who reported being the insertive partner in anal intercourse 100% of the time pretreatment, only 40% said they were the insertive partner after treatment and less than 20% reported being the insertive partner 100% of the time.⁴

The fourth study directly compared treatment outcomes between 460 heterosexual men and 96 nonheterosexual men recruited internationally from online prostate cancer sites.^10,27 While there was no difference in age at diagnosis, Gleason scores were significantly lower for GBM than heterosexual men (P = 0.02), suggesting that GBM are diagnosed earlier than heterosexual men. While the authors speculate that GBM are more likely to undergo regular health checkups, this explanation is at odds with the data reporting lower not higher PSA testing among MSM.¹²

Why GBM would be diagnosed earlier than heterosexual men is important to consider. One possible explanation lies in the PSA tests being invalidly conducted. Because vigorous stimulation of the prostate may affect the serum PSA, significantly,⁶⁰ GBM should be advised to refrain from receptive anal intercourse for at least 48 hours before a PSA test.²³ However, only 62% of GBM report being “out” to their primary physicians,⁶¹ and there are no studies advising whether physicians routinely warn men to refrain from receptive anal sex before a PSA test. Studies of how clinicians test PSA in GBM are needed to examine whether invalid PSA testing is contributing to this disparity. A second hypothesis is that physical trauma to the prostate (e.g., from repeated receptive anal sex) could increase serum PSA levels.⁴⁹

No differences were found in the type of treatment received, urinary incontinence, bone pain (marker of disease progression), and use of antidepressants (proxy for mental health).²⁷ In both heterosexuals and GBM, 60% indicated they “never or almost never” achieved an erection during sex (n.s.); of the remainder, over a third reported “never or almost never” achieving satisfaction with orgasm. GBM reported more bother by the inability to ejaculate than heterosexual men (P < 0.5).²⁷ Of the 526 men who answered their questions on anal intercourse, 27% (16% of heterosexual and 75% of GBM) reported a history of anal intercourse.¹⁰ Most (59%) GBM reported change in anal intercourse, posttreatment, almost half (46%) ceasing it. Before treatment, 58 GBM were insertive partners; of these, 14 (24%) changed to exclusively receptive partners, posttreatment. None of the GBM who were exclusively receptive before treatment changed roles, posttreatment.¹⁰

The fifth study appears to be the first National Institutes of Health (NIH) funded study of GBM with prostate cancer. This unpublished R03 study focused on quality-of-life. In comparing 341 heterosexual men with 111 gay men, Allensworth-Davies reports gay men had worse urinary and bowel functioning scores, lower masculine self-esteem, less partner affection, and more treatment regret than heterosexual men.ⁱⁱ However, he found no sexual differences (possibly due to wording differences in the sexual questions⁸).

The major conclusion of this quantitative literature review is that there are inadequate studies to be confident of findings, and where differences are identified, they are based on small convenience samples of questionable power and unknown generalizability. The state of science in this area is one of neglect. The largest study relies on an international sample, but PSA testing and treatment may vary by country masking relevant findings for the United States.⁶² Taken together, the quantitative studies show GBM to have poorer treatment outcomes on multiple measures, including sexual functioning and quality of life. Where anal intercourse has been studied, there is evidence of shifts in role-in-sex by some and cessation of anal sex by others. More research is needed to establish the reliability of these findings and to resolve discrepant results.

In the absence of empirical evidence, clinical recommendations for GBM appear based in extrapolations from predominantly heterosexual male samples and qualitative single-case reports. Using these methods, for almost all men (including GBM based on single-case reports), prostate cancer treatment negatively impacts sexual functioning,^63–65 sense of masculinity,^63,66,67 and/or self-esteem.^68–71 The most common sequelae of treatment are erectile difficulties (51%–60% report problems 24 months posttreatment⁷²) and urinary incontinence (7%–14% at 24 months⁷²).⁵

Qualitative studies, commentaries, and case reports

The first multiple-subject study of GBM with prostate cancer appears to be a focus group study (N = 36) conducted in Connecticut in the late 1990s. This concluded that gay men have little-to-no understanding of the prostate or the sexual challenges associated with prostate cancer and its treatment.⁹

Sexual effects

Sexual function is an important component of health⁷³ and predictor of quality of life,^74,75 including for older men.^73,75,76 While prostate cancer affects GBM in many of the same ways as heterosexual men, some of their concerns may differ.⁴⁰ Anecdotal evidence shows that GBM with prostate cancer face unique challenges, including the loss of the prostate as a site for sexual pleasure in receptive anal sex,^23,77 loss of ejaculate (which authors emphasize is more central in gay sex^17,32,34), persistent rectal irritation or pain sufficient to prevent receptive anal sex,^5,30 and erections too weak for insertive anal sex³⁴ (Anal penetration is estimated to require 33% more rigidity than vaginal penetration⁷⁸). Weak erections may prevent GBM treated for prostate cancer from using condoms, increasing risk of HIV transmission⁷⁹; however, case studies are lacking.

Stigma

The sexual effects of prostate cancer carry a stigma leading some GBM to conclude they are sexually undesirable or less than other GBM.²⁵ Prostate cancer in GBM intersects with issues of minority status,^13,17 discrimination,¹⁷ stigmatization,^17,68 less familial support,^{43,44,77,80,81} and less social support.^44,77,80,81 While some GBM may develop “an inner strength to meet the challenges of prostate cancer,”²⁵ others report profound shame at their own ignorance about prostate cancer,³⁴ grief at the diagnosis,²⁵ poor body image posttreatment,¹⁶ and premature aging.³² GBM may wonder when and if GBM will coalesce around prostate cancer in the way that GBM came together to fight HIV/AIDS.¹⁷ For HIV-positive GBM, prostate cancer may be one more medical complication to address in an already medicalized life.¹³

Experience of treatment by GBM

LGBT health disparities accessing medical care exist.¹ Challenges navigating (real or perceived) heterosexual bias in the medical setting,^{5,17,22,24,31,77} support groups,^19,22,34 and health systems^17,77 all worsen treatment outcomes³³ and mental health.^4,33 Distrust of the medical community⁵ and reluctance to disclose sexuality to providers^19,77 are common barriers, with 21% of 2560 older LGBT (aged 50–95) reporting they are not “out” to health providers and 13% reporting homophobic care.⁸² One explanation is that “Many gay men have had bad experiences with the healthcare system and it is difficult for them to be open with their urologist about the fact that they are gay.”⁸³

GBM may experience prostate cancer treatment as heteronormative.^20,84,85 GBM with prostate cancer report that healthcare providers fail to ask about sexual orientation during initial consultations, may assume they are not sexually active, and/or assume they are heterosexual.¹⁷ Goldstone³⁰ describes communication with one's doctor, as critical, but notes in his experience as a surgeon that gay men may be embarrassed to ask about sexual function. Older gay men with prostate cancer may have greater difficulty disclosing their sexuality to healthcare providers and/or involving partners than younger GBM who came out, post-Stonewall.⁴⁰

In an online focus group study (N = 10 Australian GBM), participants were mostly satisfied with their general practitioners.²⁵ In contrast, urologists were identified as particularly unhelpful: “The conservative hetero-normative and sometimes homophobic nature of those involved in the medical process of prostate cancer resulted in distress, dissatisfaction and negative psychological impact for participants.”²⁵ As one participant noted, “… we need to have urologists clued up to deal with gay men, we need understanding that our needs and issues are not the same as (those of) a heterosexual man.”²⁵

Education materials are also problematic. Dowsett³⁵ describes his experience this way: “All the brochures I was given by helpful nurse counsellors never mentioned gay men with prostate cancer. … just using ‘partner’ does not render any text, non-heterosexist. No mention is made of gay men who might also be HIV-positive, or where a gay male couple might both have the disease. And, of course, there is no mention of gay sex.”³⁵ GBM describe the information on postoperative sexuality in Australia as “disingenuous,” “coy,” and “Victorian,” ²⁹ while the leading resource in the Unites States for patients only addresses sex as vaginal intercourse.⁸⁶ Clinicians in North America affirm concerns about treatment being heteronormative and alienating in the United States as well,^17,40 while case studies note exceptions.^19,31

Rehabilitation recommendations for GBM

Rehabilitation options for erectile dysfunction include PDE-5-inhibiting drugs (e.g., Viagra), the vacuum pump, and, less commonly, penile injections (e.g., Caverject™) or surgical prosthesis. Rehabilitation treatment is not standardized. Where rehabilitation is offered, it typically involves one to two sessions with a nurse educator to introduce Kegel exercises (for incontinence), the vacuum pump, and erectile enhancing medications. Given the challenges identified above, this appears insufficient to address the needs of GBM. Rehabilitation may encourage frequent sexual stimulation as soon as possible postsurgery to improve the chance of (re)-stimulating erectile activity.³⁴ Recovery can take up to 3 years. There are no studies of the effects of rehabilitation for GBM with prostate cancer. It is not known how many GBM are offered rehabilitation, what is offered, what they choose, and, most importantly, outcomes.

Mental health and quality of life

Prostate cancer and its treatment have significant effects on mental health, specifically anxiety and depression,^17,87 as well as quality of life.³³ Race/ethnicity and sexual minority status are significant negative predictors of quality of life posttreatment for prostate cancer.¹⁴ Since older GBM are already at a higher risk of depression^88–91 and suicide^92–97 than other men, the additional impact of prostate cancer treatment on mental health warrants study.

Case studies of GBM with prostate cancer confirm significant mental health challenges, posttreatment.¹⁹ Where active surveillance is undertaken, cancer anxiety is an independent predictor of which men move from active surveillance to treatment.⁹⁸ Blank⁵ concludes that while the poorer sexual outcomes for GBM need research, the negative quality-of-life impact of treatment adds urgency.

Identity challenges

In a qualitative study of 14 heterosexual men and 4 homosexual men, prostate cancer and erectile dysfunction were identified as major threats to masculine identity.⁶⁸ GBM experience similar loss of masculine identity to heterosexual men.²⁵ For one man undergoing androgen deprivation therapy, feminizing side effects of treatment further eroded his sense of male identity, leading him to describe himself as experiencing female menopause in a male body.²⁵ For other men, erectile dysfunction, loss of ejaculation, loss of penile length, incontinence, and loss of libido combine to leave them identifying as “sexually undesirable” and “damaged goods.”²⁵

How prostate cancer treatment affects the identity of GBM as gay or bisexual does not appear to have been studied, directly. Clearly, some GBM change their role in sex,²⁵ which may change their identity as “tops,” “versatiles,” or “bottoms.” Others may shift the focus away from anal sex to oral sex and masturbation.¹⁹ Both these changes may influence the identity of GBM as gay/bisexual and, more broadly, as sexual beings. In turn, cessation of sex may influence other parts of identity, such as a sense of being valued, valuable, or old.³²

Social support

Compared to heterosexuals, GBM experience less familial^{43,44,77,80,81} and social support.^44,77,80,81 Social support may also be structured differently for GBM with prostate cancer.³⁵ King et al.⁹⁹ studied seven areas of support for men with prostate cancer, identifying one-on-one peer support and support from partners as the two that men with prostate cancer value the most, while highlighting the need for improved access to cancer specialist nurses, individually tailored supportive care, and psychosexual support for treatment side effects.⁹⁹ For GBM, case reports also affirm the importance of talking to other GBM about their cancer.^17,31,87,100 However, general support groups for men with prostate cancer may have adverse effects for GBM if the groups further alienate them from discussing their sexual concerns.³¹ While support groups specifically for GBM with prostate cancer may be ideal, in all but the largest cities, they may not be viable.¹⁰⁰ Instead, one-on-one peer support from a GBM prostate cancer survivor³¹ and online support groups for GBM^87,100 appear the two forms of prostate cancer support most commonly accessed. The effects of such support have not been evaluated.

Interpersonal and relationship challenges

Some relationship researchers term prostate cancer a “couple's disease” because the illness and treatments affect the well-being of both patients and their partners.¹⁰¹ Partner involvement in prostate cancer treatment in heterosexual couples improves outcomes,¹⁰² however, GBM may be less likely to involve their male partners in treatment.⁷⁷ Extrapolating from heterosexual studies, partners may experience more distress than the man diagnosed,^101,103,104 want to be involved in information gathering and decision-making, and benefit from support and inclusion in therapy.^101,105,106 Wittmann et al.¹⁰⁷ interviewed 20 heterosexual couples following radical prostatectomy. Most of the men reported erectile dysfunction, lost sexual confidence, and decreased sexual activity. Couple's engagement in intentional sex, the patients' acceptance of erectile aids, and the partners' interest in sex aided the recovery of sexual intimacy.¹⁰⁷

We found three case reports documenting effects of prostate cancer on GBM couples: one where the patient was treated with radical prostatectomy,³¹ one where both were diagnosed at about the same time and treated with proton therapy,¹⁹ and an exploratory study of sexual functioning in three gay couples, where one was treated for prostate cancer.¹¹ In the first, the patient reported diminished penile sensation and sexual interest, postsurgery. His partner reported coping with these changes and reduced spontaneity through increased masturbation to pornography, which was not part of their lives, prediagnosis.³¹ In the second case, the couple reported that after an initial recovery period of avoiding sex (because of pain in orgasm in one partner), masturbation with one partner holding the other was initiated. Long-term oral sex replaced anal sex as “very effective and enjoyable even without a full erection.”¹⁹ In the third, acknowledging, accommodating, and accepting change in sexual experience emerged as metathemes across the couples.¹¹ The authors note that gay couples may engage in novel accommodation practices, such as change in sex roles and open relationships, which have not been noted in heterosexual couples.¹¹ Given the lack of research on partners and couples, study of the effects of prostate cancer treatment in GBM needs to include study of the effects on partners, relationships, and on couples' agreements.³¹

Given gender differences, the literature on female partners of men with prostate cancer should be extrapolated to male partners with extreme caution. For example, some heterosexual studies suggest that (female) partners are less concerned about sexuality than the patients,^104,108 which may not generalize to male partners. Conversely, male partners may have unique concerns such as fear of infectivity that female partners may not experience. Caring for a partner with prostate cancer may be experienced differently, for example, whether he will continue to be “the lover, partner and friend, or will he become a nurse?”³¹ Studies of fears of infection and the impact of caregiving on male partners are needed.

In addition, prostate cancer's impact on single GBM⁷⁷ and casual sex partners^5,17 needs research. Single GBM may be more likely to experience problems in care provision and reduced social support,³⁵ challenges in dating, coming out as living with prostate cancer, fear of rejection, and diminished hope of finding a long-term relationship.²⁵ Reluctance to engage in new sexual encounters appears a common challenge.²⁵

Sexual rehabilitation treatment in GBM

We could find no studies assessing the effects of sexual rehabilitation treatment on GBM, so we briefly summarize the literature on treatment effectiveness in predominantly heterosexual men. Confirming need, 51% of 1977 men treated for prostate cancer had sought treatment for erectile dysfunction within 5 years of treatment.¹⁰⁹ At 60 months, the most common treatments tried included sildenafil (aka Viagra) either taken alone (16.7%) or in combination with other treatments (20.9%), vacuum devices (16.5%), and penile injections (11.1%). In a second study of 1288 men, 5 years postdiagnosis, only 28% reported erections firm enough for vaginal intercourse.¹¹⁰ Sildenafil was the most common erectile aid (43%) with 45% of users reporting it helped “somewhat” or “a lot.”

The effectiveness of individual treatments has been evaluated. Sildenafil appears effective in 29%–40% of men posttreatment for prostate cancer and most effective in younger men and men in whom both neurovascular bundles (NVBs) have been spared.¹¹¹ Reports conflict regarding whether sildenafil is effective when both NVBs have been excised. In addition, sildenafil may be ineffective in the first 9 months, postsurgery.¹¹¹ In a small (N = 42 men) uncontrolled study, early daily intervention with a vacuum erection device significantly lowered risk of loss of penile length.¹¹²

Like the literature on GBM, Latini et al.⁴⁰ describe the literature on sexual rehabilitation interventions following prostate cancer treatment (for any men) as very limited. In randomized controlled trials, a four-session psychoeducation intervention showed significant improvements in male overall distress and sexual function at 3 months.¹¹³ Similarly, men who received a six-session intervention to model sexual communication with partners reported improved sexual functioning and less sexual bother at 4, 7, and 12 months than the control group men.¹¹⁴

Discussion

As noted in the IOM report¹ and confirmed by this review, prostate cancer in GBM is severely under-researched.^5,14 Part of the problem appears to be structural. Health research on GBM for the last 30 years has focused on HIV/AIDS, leaving chronic diseases in GBM almost unstudied.¹ Now, with ARV treatments having greatly reduced AIDS mortality, large cohorts of GBM are entering age groups in which prostate cancer is commonly diagnosed. Recruitment of GBM in meaningful numbers for study is also a barrier, exacerbated by professionals reluctant to take detailed sexual histories, and clinical systems reluctant to collect data on sexual orientation or gender of sexual partners. This leaves GBM with prostate cancer as an invisible, geographically dispersed hard-to-recruit population. In addition, prostate cancer remains a stigmatized disease in the wider population and within the gay community. Electronic medical records that capture data on sexual orientation and the recent development of online support groups for GBM with prostate cancer are two promising ways to overcome these structural challenges.

In addition, heterocentric definitions of functioning limited to penetrative sex are problematic. While DSM-5¹¹⁵ defines “sexual dysfunction” as “a clinically significant disturbance in a person's ability to respond sexually,” erectile functioning in prostate cancer treatment is typically operationalized as “sufficient for vaginal penetration.”^5,116,117 This gold standard is irrelevant for sex between men. Physiologically, anal penetration requires a greater degree of penile rigidity than vaginal penetration,^28,30 which potentially explains the poorer outcomes of prostate cancer treatment for GBM. Population-appropriate measures and definitions need to be developed before the effects of prostate cancer treatment in GBM can be enumerated.

Six directions for future research are identified. First, methodological research is needed to identify ways to locate, recruit, and retain GBM with prostate cancer in studies and to develop population-appropriate definitions and measures. Second, more formative research is needed. In particular, in-depth examination of the effects of treatment on sexual functioning behavior and identities will advance a comprehensive sexological understanding of the experience of prostate cancer in GBM. Third, empirical studies to quantify the prevalence and incidence of sexual problems and effects of treatment by treatment type will be critical to informing clinical care. Fourth, comparative studies of treatment preferences for GBM and heterosexual men should confirm whether GBM are more, as, or less likely than heterosexuals to choose surgical intervention. Fifth, intervention studies to address the rehabilitation needs of GBM with prostate cancer are needed to develop evidence-based interventions tailored for this population. Finally, the training needs of urologists, surgeons, oncologists, and other specialists providing services to GBM with prostate cancer need to be identified and curricula developed to ensure culturally competent providers capable of addressing the sexual health needs and care of this population.

Conclusion

GBM appear to be screened for prostate cancer less than other men, diagnosed with prostate cancer at about the same rate, but have poorer sexual function and quality-of-life outcomes. Part of the problem is lack of sexual rehabilitation treatment for GBM, and part is the lack of research to guide development of appropriate treatment. While GBM may experience similar challenges following treatment to other men, because the sexual context is different, treatment outcomes appear worse. Substantial research will be needed to address this health disparity.

Acknowledgments

This article was developed as part of the Restore study, a National Cancer Institute-funded grant award titled, “Understanding the Effects of Prostate Cancer on Gay and Bisexual Men” (Grant No. CA182041; PI: B.R.S.R.). The authors warmly acknowledge Derek Johnson (project coordinator), James DeWitt (research assistant), and Angelique Lele (executive assistant) in helping to develop this article.

Author Disclosure Statement

No competing financial interests exist.