Sexual dysfunction is undoubtedly one of the most common long-term side effects of cancer and cancer treatment, yet it is still a topic that health-care providers shy away from. It has been shown that nearly all patients with cancer report some impact of cancer treatment on their sexual functioning; and when asked, half of all patients said that they desired additional care and support in the area of sexual health.1

In particular, the treatment of prostate cancer directly affects a man’s ability to have an erection. Both radical prostatectomy and radiation therapies not only damage the cavernosal nerves but can also injure the penile arteries, causing local inflammatory changes and tissue hypoxia. If not corrected, these changes will lead to a loss of smooth muscle cells, an accumulation of collagen, and eventual permanent fibrosis of erectile tissues. Conversely, hormone-ablative therapies used in the treatment of recurrent and advanced prostate cancers result in a loss of erections from an absence of testosterone. Estimates of the incidence of erectile dysfunction (ED) following prostate cancer treatment vary widely, but likely up to 80% of men have some difficulty. It is important that men are explicitly made aware of this fact, as most overestimate their expected sexual functioning after treatment. In one study, men were found to have anticipated their sexual functioning to be 12% to 45% better than it actually was 1 year following prostatectomy. This unrealistic expectation was also found to be strongly related to their level of distress.2

Standard Management of ED

Very few men recover erectile function without intervention. There are several options available in the treatment of ED following prostate cancer treatment. Management usually involves the use of one or more erectile aids, including oral phosphodiesterase type 5 (PDE-5) inhibitors, vacuum erectile devices, alprostadil administered as an intraurethral suppository or as an intracavernosal injection, or penile prosthesis implants. Each has its own advantages and disadvantages, and no one method is right for everyone. Although the PDE-5 inhibitors are the most commonly used erectile aids, they generally have a low response rate with only one-third of men with prostatectomy-induced ED reporting functional erections after use.3

Naturopathic Approaches to ED

With very few exceptions, there has not been any research published on the use of natural therapies for the treatment of ED specifically related to prostate cancer treatment. However, it is worthwhile to briefly review the body of research that exists regarding the use of natural agents to improve erectile function overall, as these approaches can be helpful when used as part of a comprehensive management plan for prostate cancer treatment-induced ED.

Lifestyle Factors

In addition to not smoking and maintaining a healthy body weight, minimizing stress and regular exercise are important aspects of a comprehensive treatment plan for ED. The sympathetic nervous system is responsible for maintaining the penis in its flaccid state. Adrenaline is a very potent natural antierection chemical, and high serum levels associated with increased stress will undermine any treatment designed to improve erectile function. Stress management will therefore be the cornerstone of any integrative treatment of ED.

Physical fitness has long been known to be correlated with erectile function. Most notably, a study following men after completing radiation therapy for their prostate cancer found that active men had significantly better erectile function scores compared with inactive men.4 Additionally, in men receiving androgen deprivation therapy, a 12-week exercise program successfully prevented a decrease in their sexual activity and libido compared with the men undergoing usual care alone.5

Acupuncture

A recent systematic review of the existing clinical trials studying acupuncture for the treatment of ED found that in addition to several positive uncontrolled trials, three out of four randomized controlled clinical trials demonstrated that acupuncture had a significant therapeutic effect compared to sham acupuncture.6

Nutritional Supplements

L-arginine, and its precursor L-citrulline, are converted in the penile endothelial cells to nitric oxide, which is required for proper erectile function. In addition to single agent studies, several clinical trials have also looked at the use of L-arginine combined with other substances such as a Pycnogenol and adenosine monophosphate, as these agents may work synergistically by also increasing nitric oxide production through stimulation of the enzyme nitric oxide synthase.7^–13 Additionally, a recent rat study showed that L-arginine administered after pelvic radiation prevented the accumulation of connective tissue in the penis by 18% and elastic fiber deposition by 61%.14 Similarly, L-carnitine has also been shown to increase nitric oxide levels, and there is evidence suggesting that PDE-5 inhibitors may be more effective if used in combination with acetyl-L-carnitine and propionyl-L-carnitine in men with ED following prostatectomy.15

Botanicals

There is a growing body of evidence to support the use of ginseng and yohimbine for the treatment of ED of various causes. A systematic review of seven randomized controlled clinical trials of Korean red ginseng root showed it to be significantly more effective than placebo in the treatment of ED.16 Similarly, yohimbine has also consistently been shown to be more effective than placebo in clinical trials evaluating its use in the treatment of ED.17

Other botanical agents have not been the subject of as much study, but a single randomized controlled trial of maca root showed improved erectile function and psychological scores compared with placebo.18 Additionally, a previous study demonstrated that maca supplementation improved libido in healthy men without altering serum testosterone levels.19

There have been two randomized clinical trials assessing the effectiveness of saffron on ED. The first, a crossover study with sildenafil failed to show an effect, but the second demonstrated a significant improvement over placebo in erectile function in men with fluoxetine-induced ED.20,21 Similarly, the effect of tribulus on ED has also been studied with mixed results. Although it was not found to be effective as a single agent, a patented combination product of tribulus, an algae extract, and polymers of D-glucosamine and N-acetyl-D-glucosamine was shown to significantly improve several measures of sexual function in two randomized controlled trials.22–24

Although early studies with ginkgo showed benefit in selective serotonin reuptake inhibitor-induced ED, follow-up trials have shown no effect compared with placebo.25^,26

A Few Words of Caution

When treating ED in men who have an active prostate cancer or those who are at high risk of recurrence, it is important to keep a few cautions in mind. In animal studies, high doses of L-arginine have been shown to stimulate the release of various growth factors, including growth hormone, insulin-like growth factor 1, insulin, and prolactin and a diet high in L-arginine compared to a control diet was shown to promote cancer growth in mice.27 Additionally, tribulus has been shown to increase testosterone levels and bind testosterone receptors that could potentially support prostate cancer cell growth.28 As such, the use of these natural agents, although they may be useful in improving erectile function, may not be appropriate for many patients with a history of prostate cancer.

The Emotional and Relational Aspects of Prostate Cancer and Treatment-Related ED

Despite the many interventions for erectile dysfunction, many couples report that they are dissatisfied with their sexual relationships and eventually cease engaging in sexual relations altogether. While the focus has largely been on improving erectile function, the sexual impact of prostate cancer treatment is multifactorial. Physically, many changes can occur after treatment in addition to ED. Depending on the therapies used, these may include decreased libido, loss of ejaculate fluid, penile shortening, climacturia, dysorgasmia, and body composition changes including the loss of muscle mass and gynecomastia. All of these can take a toll on a man’s self-esteem and sense of masculinity. In fact, the diagnosis and treatment of any cancer can challenge several social and cultural definitions of masculinity, including physical strength, self-reliance, being a provider, and maintaining control. Additionally, sexuality itself is an important aspect of adult self-concept, and sexual function is often a key component of male identity. As such, men may need to renegotiate a new masculine identity following their diagnosis and treatment for prostate cancer.29 This will inevitably have a significant impact on a man’s sexual relationships, and it is important to remember that prostate cancer does not only affect the patient, but also greatly affects their partners’ well-being. While this may seem obvious, it is all too often overlooked or dismissed as unimportant in the medical setting.

A great deal of suffering could be avoided though open and honest communication. However, this is often the first time a couple has needed to communicate about sexual issues. Without education and support around this, the necessary discussions often do not occur. Patients frequently feel embarrassed and try to avoid discussions regarding sex. Over time, this can lead men to withdraw physically and emotionally from their partners. When this happens, partners often feel abandoned, lonely, and isolated in the relationship. Specifically, communicating relational values between partners is especially important. Both men and women commonly overestimate the value that their partner places on physical pleasure compared with relational intimacy, yet it has been shown that the withdrawal of intimacy and affection, not coital sex, causes the biggest stress on a relationship.30

Three common traits were found among couples who successfully maintained satisfying sexual intimacy after prostate cancer treatment; namely, persistence, flexibility, and acceptance.31 Just as men may need to renegotiate a new masculine identity following their diagnosis and treatment, couples may need to redefine what constitutes good sex. Couples can learn how to have satisfying sexual experiences whether or not an erection is possible. Although sex will often be different after treatment, it can definitely still be enjoyable.

Sexual health promotion is an important part of holistic medicine, and patients with cancer and their partners are clear in their desire to have more support from health professionals in this area. There are many options available in the management of ED, and naturopathic approaches may be important additions to a comprehensive treatment plan to maximize sexual rehabilitation during and after prostate cancer treatment. Although not always stressed, the sexual effects of prostate cancer affect both patients and their partners, and it is important for all health-care providers to reassure couples that even though prostate cancer treatment may impair sexual function, sexual activity and certainly relational intimacy need not end.

Notes

1. Bober SL and Varela VS. Sexuality in adult cancer survivors: challenges and intervention. J Clin Oncol. 2012;30(30):3712–3719.

2. Soloway CT et al. Sexual, psychological and dyadic qualities of the prostate cancer “couple.” BJU Int. 2005;95(6):780–785.

3. Montorsi F, McCullough A.J. Efficacy of sildenafil citrate in men with erectile dysfunction following radical prostatectomy: a systematic review of clinical data. Sex Med. 2005;2(5):658–667.

4. Thomas RJ et al. Lifestyle factors correlate with the risk of late pelvic symptoms after prostatic radiotherapy. Clin Oncol (R Coll Radiol). 2013;25(4):246–251.

5. Cormie P et al. Exercise maintains sexual activity in men undergoing androgen suppression for prostate cancer: a randomized controlled trial. Prostate Cancer Prostatic Dis. 2013;16(2):170–175.

6. Tsai MY et al. Overview of the relevant literature on the possible role of acupuncture in treating male sexual dysfunction. Acupunct Med. 2014;32(5):406–410.

7. Chen J et al. Effect of oral administration of high-dose nitric oxide donor L-arginine in men with organic erectile dysfunction: results of a double-blind, randomized, placebo-controlled study. BJU Int. 1999;83(3):269–273.

8. Cormio L et al. Oral L-citrulline supplementation improves erection hardness in men with mild erectile dysfunction. Urology. 2011 Jan;77(1):119–122.

9. Aoki H et al. Clinical assessment of a supplement of Pycnogenol® and L-arginine in Japanese patients with mild to moderate erectile dysfunction. Phytother Res. 2012;26(2):204–207.

10. Ledda A et al. Investigation of a complex plant extract for mild to moderate erectile dysfunction in a randomized, double-blind, placebo-controlled, parallel-arm study. BJU Int. 2010;106(7):1030–1033.

11. Stanislavov R et al. Improvement of erectile function with Prelox: a randomized, double-blind, placebo-controlled, crossover trial. Int J Impot Res. 2008;20(2):173–180.

12. Stanislavov R, Nikolova V. Treatment of erectile dysfunction with pycnogenol and L-arginine. J Sex Marital Ther. 2003;29(3):207–213.

13. Neuzillet Y et al.A randomized, double-blind, crossover, placebo-controlled comparative clinical trial of arginine aspartate plus adenosine monophosphate for the intermittent treatment of male erectile dysfunction. Andrology. 2013;1(2):223–228.

14. Medeiros JL Jr et al. Protective effects of nutritional supplementation with arginine and glutamine on the penis of rats submitted to pelvic radiation. Andrology. 2014;2(6):943–950.

15. Cavallini G et al. Acetyl-L-carnitine plus propionyl-L-carnitine improve efficacy of sildenafil in treatment of erectile dysfunction after bilateral nerve-sparing radical retropubic prostatectomy. Urology. 2005;66(5):1080–1085.

16. Jang DJ et al. Red ginseng for treating erectile dysfunction: a systematic review. Br J Clin Pharmacol. 2008;66(4):444–450.

17. Ernst E, Pittler MH. Yohimbine for erectile dysfunction: a systematic review and meta-analysis of randomized clinical trials. J Urol. 1998;159(2):433–436.

18. Shin BC et al. Maca (L. meyenii) for improving sexual function: a systematic review. BMC Complement Altern Med. 2010;10:44.

19. Gonzales GF et al. Effect of Lepidium meyenii (MACA) on sexual desire and its absent relationship with serum testosterone levels in adult healthy men. Andrologia. 2002;34(6):367–372.

20. Safarinejad MR et al. An open label, randomized, fixed-dose, crossover study comparing efficacy and safety of sildenafil citrate and saffron (Crocus sativus Linn.) for treating erectile dysfunction in men naïve to treatment. Int J Impot Res. 2010;22(4):240–250.

21. Modabbernia A et al. Effect of saffron on fluoxetine-induced sexual impairment in men: randomized double-blind placebo-controlled trial. Psychopharmacology (Berl). 2012;223(4):381–388.

22. Santos CA Jr et al. Tribulus terrestris versus placebo in the treatment of erectile dysfunction: A prospective, randomized, double blind study. Actas Urol Esp. 2014;38(4):244–248.

23. Sansalone S et al. Alga Ecklonia bicyclis, Tribulus terrestris, and glucosamine oligosaccharide improve erectile function, sexual quality of life, and ejaculation function in patients with moderate mild-moderate erectile dysfunction: a prospective, randomized, placebo-controlled, single-blinded study. Biomed Res Int. 2014;2014:121396.

24. Iacono F et al. Sexual asthenia: Tradamixina versus Tadalafil 5 mg daily. BMC Surg. 2012;12 Suppl 1:S23.

25. Kang BJ et al. A placebo-controlled, double-blind trial of Ginkgo biloba for antidepressant-induced sexual dysfunction. Hum Psychopharmacol. 2002;17(6):279–284.

26. Wheatley D. Triple-blind, placebo-controlled trial of Ginkgo biloba in sexual dysfunction due to antidepressant drugs. Hum Psychopharmacol. 2004;19(8):545–548.

27. Lind DS. Arginine and cancer. J Nutr. 2004;134(10 Suppl):2837S–2841S; discussion 2853S.

28. Roaiah MF et al. Pilot study on the effect of botanical medicine (tribulus terrestris) on serum testosterone level and erectile function in aging males with partial androgen deficiency (PADAM). J Sex Marital Ther. 2015;7:1–5.

29. Gannon K et al. Re-constructing masculinity following radical prostatectomy for prostate cancer. Aging Male. 2010;13(4):258–264.

30. Beck AM et al. Sexual values as the key to maintaining satisfying sex after prostate cancer treatment: the physical pleasure-relational intimacy model of sexual motivation. Arch Sex Behav. 2013;42(8):1637–1647.

31. Ibid.