Erectile Dysfunction After Radiation Therapy in Prostate Patients

Abstract

Background: Patients who receive radiation therapy for prostate cancer can experience erectile dysfunction.

Objective: To find current research on interventions from radiation induced erectile dysfunction (RIED)

Methods: A literature review was conducted to analyze available interventions for prostate cancer patients who received radiation therapy. All sources were reviewed to obtain information on available interventions relating to RIED in prostate cancer patents.

Results: There are several options available for patients experiencing REID. The two most common interventions used are Sildenafil and Tadalafil, which are Phosphodiesterase type 5 inhibitors (PDE5I). Both have been proven effective and are relatively low risk. Therapy, an alternative to medication, has also been theorized to improve erectile dysfunction by easing post-treatment anxiety and depression.

Conclusion: PDE5Is have data supporting their effectiveness and relatively low side effects. If one PDE5I, such as Sildenafil, causes unmanageable side effects Tadalafil could be better for those patients. Some data supports therapy as an option, but no research studies have been found on the therapy model in this review of literature.

Introduction

In some cases, radiation therapy is not only a blessing, but also a curse. This is often the case for men who receive radiation for prostate cancer. Throughout their treatment, penile tissue and nerves can become damaged resulting in radiation induced erectile dysfunction (RIED). They are given more years of their life to live but with a costly side effect. RIED can be very traumatic for the patient, decreasing their long-term quality of life. Currently, Phosphodiesterase type 5 inhibitors (PDE5I) are the primary medication used to RIED and the main two are Sildenafil and Tadalafil. Both are relatively safe but do have some risks associated with them. Along with radiation directly causing erectile dysfunction, anxiety and depression related to radiation treatment may also be the cause. Some researches created a therapy model that can be successful in helping patients with anxiety and depression caused erectile dysfunction.

Methods

Methods used to research literature relating to RIED was primarily with EBSCOhost through the University of Wisconsin-La Crosse library. Secondly, some sources used came from google scholar, but only articles that were free to everyone.  Some of the original research was not within the last five years but there were studies that reviewed them recently. The terms I used to search in EBSCOhost and google scholar were: “radiation therapy, erectile dysfunction, counseling, sildenafil, and Tadalafil.” 

Review of Literature

Radiation induced erectile dysfunction (RIED) is a side effect many prostate patients encounter as a result of radiation therapy. Since RIED are caused by different factors, there are different strategies used to manage it.1 Sildenafil, or more commonly known as Viagra is one mode of intervention that can be utilized by patients who encounter RIED. Sildenafil is a PDE5I and works by preventing the degradation of cyclic guanosine monophosphate (cGMP) in the penile tissue.1,2 Sildenafil causes vascular dilation in penile tissue, resulting in a response to sexual stimulation1,2 Having options for prostate cancer patients gives them hope as they battle treatment side effects of pelvic radiation. According to Incrocci,1 the effects Sildenafil had from a double-blind study showed there is an increase of sexual function in 55 percent of patients. Incrocci1 shows that this is a viable treatment option for men experiencing RIED and it can help them to regain sexual function. Since the cause of RIED cannot be narrowed down to only one type of tissue that was damaged from prostate radiation treatment, this drug is not going to work for everyone. Another way radiation can disrupt the process of gaining an erection is damage to the cavernous nerves that are located in close proximity to the prostate.1-3 As a result of the complicated nature of gaining an erection, Incrocci1 shows that 24 out of the 60 participants in the double-blind study continued to have success with sildenafil after two years. However, 36 participants reported that they stopped taking sildenafil because they did not see the desired results.1 This treatment did not work for most of the patients, but it is still a good treatment option because the side effects from Sildenafil are minimal.

According to Incrocci1, 16 percent of those participating in the double-blind study stopped taking the medication specifically as a result of side effects. Side effects have a relatively low occurrence, but it is still a factor that needs to be considered. In a study conducted by Taylor et al.4, 128 men were prescribed sildenafil with an average age of 58.7. Of the 128 men, the most common side effects experienced were headaches, flushing, and dyspepsia which occurred in 16 men, 14 men, and 6 men respectively.4 However, sildenafil’s half-life is four hours and these symptoms were short lived resulting in only three percent of men exhibited side effects after 12 hours.4 Sildenafil is shown to be safe for patients to take with relatively insignificant side effects. In addition, even if the side effects are present, they are short lived in many patients which makes it an option for patients to try and decide if it is beneficial to them.

Another PDE5I drug used in the treatment of erectile dysfunction is Tadalafil. Tadalafil and Sildenafil both work by the same mechanism, however, Tadalafil has a much longer lasting effect in the body.5 In a study conducted by Choi et al.5, 180 men with erectile dysfunction were enrolled in a trial testing the usefulness and side effects of Tadalafil. However, only 120 men completed the 12-week trial.5 These men were separated into two groups. One group received 5mg every day and the second group received 5mg every other day.5 As a result of this trial, there was no significant difference between the two groups in relation to return of erectile function. Effectiveness of Tadalafil was analyzed using the international index of erectile function which includes 15 questions long relating to their sexual function. As a result of this trial, Tadalafil increased the average score of all participants from 13.4 to 18.7.5 Tadalafil has shown to be an effective method to overcome erectile dysfunction that prostate patients experience as a result of radiation therapy.

Tadalafil is also useful in its flexibility of when it is taken and when the erectile function is received. Tadalafil has a much longer half-life when compared to Sildenafil, 17.5 hours and four hours respectively.4,5 As a result, men who use Tadalafil are able to have erectile function up to 36 hours after taking the medication.4,5 In addition to having a long lasting effect on erectile function, there is also a quick response to when Tadalafil is first taken. This medication can have an effect on the body within 16 minutes for some men.4 This flexible schedule can make it easier for men because it does not require as much planning. Another result of its long half-life is its duration of side effects. The side effects last much longer with Tadalafil than they do with Sildenafil. In the study conducted by Taylor et al.4, 24 of the 214 men who received Tadalafil, reported having experienced headaches. In addition, 11 men experienced dyspepsia and four men experienced flushing.4

Another option that is available for patients is therapy. It is a resource that not many people consider but it is a risk-free intervention to try. As patients go through the cancer treatment process for radiation therapy, they experience a lot of fears and emotions. One meta-analysis of 4494 patients reported high anxiety and depression rates which were 15.09 percent and 15.06 percent respectively.5 As a result, these patients could be facing phycological instances of erectile dysfunction and could benefit from a treatment option that does not include medication with additional side effects. Men undergoing prostate cancer treatment can hear the words erectile dysfunction and automatically have anxiety, which actually induces it. One research group produced a model that they think would help resolve some of the erectile dysfunction symptoms related to anxiety. According to Kimmes et al.7, the most important parts of this treatment is to be sex positive and practice mindfulness. Mindfulness is important because it does not ignore the problem but instead brings it to light in a nonjudgmental way.7 The therapy model is completed in three levels and the first one consists of just meeting the couple and evaluating out the situation.7 This is a way to find out what the couples needs are and dialog to become comfortable talking about this subject together.7 The middle level is focused on the male becoming comfortable and mindful of the situation.7 The last level is for the couple to talk about ways to reduce anxiety together and reward each other for mindful thinking by doing something nice for them.7 For example, one could do all the laundry that day as a nice gesture of their appreciation. After these levels, the couple should feel more comfortable with each other, which will lower their anxiety level and potentially improving erectile dysfunction.

Conclusion

As a result from current literature on RIED, there are interventions available for prostate patients who experience RIED with relatively low side effects.1,4 Some medications might not work for everyone but there is a relatively small risk in trying them out. It is still important for men with RIED to talk with their doctor to find what is right for them. There is an abundance of research showing PDE5Is can help solve ED. There is not a lot recent research though, which could mean it is accepted in present day medicine as being effective. Therapy can also help some patients who are experiencing erectile dysfunction and need to get by some mental barriers to help. For example, a lot of patients experience anxiety and depression going though treatment, which can cause erectile dysfunction by themselves.7 The sources I found that covered therapy and erectile dysfunction did not have much data showing their theory would work.7 They had data showing that it could work but did not actually study a group a couples going through the therapy. I think it would be beneficial for someone to create a research study on the therapy plan I talked about in order to quantify if it would work in practice.

References

1. Incrocci L. Radiotherapy for prostate cancer and sexual health. Transl Androl Urol. 2015;4(2):124–130. doi:10.3978/j.issn.2223-4683.2014.12.08. Published April 4, 2015. Accessed October 9, 2019.
2. Albaugh J. 50 years of erectile dysfunction: How far have we come? Urologic Nursing. 2019;39(5):262-264. doi:10.7257/1053-816X.2019.39.5.262. Published September 1, 2019. Accessed October 9, 2019.
3. Voznesensky M, Annam K, Kreder K. Understanding and managing erectile dysfunction in patients treated for cancer. Journal of Oncology Practice. 2016 Jun;12(6):596. 2016;12(4):297–304. doi:10.1200/JOP.2016.010678. Published September 21, 2016. Accessed October 9, 2019.
4. Taylor J, Baldo O, Storey A, Cartledge J, Eardley I. Differences in side-effect duration and related bother levels between phosphodiesterase type 5 inhibitors. BJU International. 2009;103(10):1392-1395. doi:10.1111/j.1464-410X.2008.08328.x. Published April 27, 2009. Accessed October 9, 2019.
5. Choi H, Kim J-H, Shim J-S, et al. Comparison of the efficacy and safety of 5-mg once-daily versus 5-mg alternate-day tadalafil in men with erectile dysfunction and lower urinary tract symptoms. International Journal of Impotence Research. 2015;27(1):33-37. doi:10.1038/ijir.2014.19. Published July 3, 2014. Accessed October 9, 2019.
6. Watts S, Leydon G, Birch B, et al. Depression and anxiety in prostate cancer: A systematic review and meta-analysis of prevalence rates. BMJ Open 2014;4:e003901. doi:10.1136/bmjopen-2013-003901. Accessed October 9, 2019.
7. Kimmes JG, Mallory AB, Cameron C, Köse Ö. A treatment model for anxiety-related sexual dysfunctions using mindfulness meditation within a sex-positive framework. Sexual & Relationship Therapy. 2015;30(2):286-296. doi:10.1080/14681994.2015.1013023. Published February 23, 2019. Accessed October 9, 2019.