Each month, questions with a common theme will be selected and answered comprehensively by our Steering Committee and Distinguished Faculty members. Previously answered questions will be archived each month for your reference. If you wish to submit a question, click here. To view archived responses, click here.

This Month's Question

Prostate cancer (PCa) treatment often causes erectile dysfunction (ED). What can clinicians do to treat ED associated with PCa treatment? How can phosphodiesterase type 5 (PDE5) inhibitors help these patients?

Response by Jay M. Young, MD, Posted 11/12/07

Nerve-sparing radical prostatectomy (NSRP) is the most common treatment for patients with clinically localized PCa;¹ an increasingly popular method for treating PCa is brachytherapy (BT).² The ED resulting from PCa treatment may be caused by radiation or by comorbidities (J. M. Young, written communication, November 2007). Because of the importance of preserving sexual function in patients receiving PCa treatment, clinicians should advise patients about PCa therapy options and their effects on erectile function.³ PDE5 inhibitor therapy may be used to effectively treat ED for patients receiving PCa treatment.^2,4,5

The incidence of ED associated with BT may be more prevalent than previously reported, with approximately 50% of patients experiencing ED within 5 years of BT.^6,7 Also, ED severity worsens over time after BT.^8-11 Although the initial decline in erectile function after BT may be attributed to painful ejaculation and general pain and discomfort,¹² progressive fibrosis may cause further deterioration.³ Because chronic hypoxia-induced fibrosis may result in permanent ED,¹³ screening for and management of ED should be routine in the follow-up of patients after PCa treatment.³

If taken soon after BT, PDE5 inhibitors may help preserve the erectile tissue endothelium and penile arterial blood flow, thereby minimizing corporeal fibrosis.² In a prospective review of data on 210 men who underwent BT, those who initiated PDE5 inhibitor therapy within 12 months of BT experienced significant, sustained improvement in erectile function, as measured by Sexual Health Inventory for Men scores at 18 and 36 months after BT, compared with men who received PDE5 inhibitor therapy at a median of 18 months after BT.²

Early intervention with PDE5 inhibitor therapy to increase and prevent hypoxia may improve erectile function after PCa treatment,^1,13 augment neuronal regeneration and oxygenation by enhancing nocturnal erections,¹⁴ and help preserve corpus cavernosum smooth muscle function,¹⁵ thereby preventing permanent ED.^1,13 In a novel primary prevention study of ED after NSRP, 27% of men who used PDE5 inhibitors nightly for 9 months experienced a return of normal, spontaneous erections compared with 4% in the placebo group.¹⁴ In a clinical trail of 303 patients, 71% of men who took tadalafil 20 mg every 3 days beginning the day after NSRP experienced improved erections at 6 months, as measured by patient diaries of coitus and the International Index of Erectile Function.¹⁶

PDE5 inhibitor therapy is well tolerated and improves erectile function,² but ED associated with PCa treatment may be more resistant to PDE5 inhibitor therapy than other forms of ED.⁴ Clinicians should inform patients and their partners that recovery of erectile function after PCa treatment can take months, so not having an immediate response to a PDE5 inhibitor should not be considered a failure, and the likelihood of response increases with time.^3,17 For patients who are not responsive to on-demand therapy, chronic PDE5 inhibitor therapy may be efficacious.^4,5

Considering the importance of erectile function and the high prevalence of PCa, to optimize PCa treatment success, clinicians should counsel patients about therapy options and their effects on sexual function.³ PDE5 inhibitor therapy may provide a safe and effective way to treat ED associated with PCa treatment,² and in difficult-to-treat ED, chronic dosing may help restore a patient’s erectile function.^4,5

References

1. Kendirci M, Hellstrom WJ. Current concepts in the management of erectile dysfunction in men with prostate cancer. Clin Prostate Cancer. 2004;3:87-92.

2. Schiff JD, Bar-Chama N, Cesaretti J, Stock R. Early use of a phosphodiesterase inhibitor after brachytherapy restores and preserves erectile function. BJU Int. 2006;98:1255-1258.

3. Pommerville PJ. From bedside to bed: recovery of sexual function after prostate cancer. Can Fam Physician. 2005;51:941-943.

4. McMahon C. Efficacy and safety of daily tadalafil in men with erectile dysfunction previously unresponsive to on-demand tadalafil. J Sex Med. 2004;1:292-300.

5. Rajfer J, Aliotta PJ, Steidle CP, Fitch WP III, Zhao Y, Yu A. Tadalafil dosed once a day in men with erectile dysfunction: a randomized, double-blind, placebo-controlled study in the US. Int J Impot Res. 2007;19:95-103.

6. Merrick GS, Butler WM, Galbreath RW, Stipetich RL, Abel LJ, Lief JH. Erectile function after permanent prostate brachytherapy. Int J Radiat Oncol Biol Phys. 2002;52:893-902.

7. Merrick GS, Wallner KE, Butler WM. Management of sexual dysfunction after prostate brachytherapy. Oncology (Williston Park, N.Y.). 2003;17:52-62.

8. Feigenberg SJ, Lee WR, Desilvio ML, et al. Health-related quality of life in men receiving prostate brachytherapy on RTOG 98-05. Int J Radiat Oncol Biol Phys. 2005;62:956-964.

9. Masson P, Lambert SM, Brown M, Shabsigh R. PDE-5 inhibitors: current status and future trends. Urol Clin North Am. 2005;32:511-525.

10. Merrick GS, Butler WM, Wallner KE, et al. Erectile function after prostate brachytherapy. Int J Radiat Oncol Biol Phys. 2005;62:437-447.

11. Ponholzer A, Oismüller R, Somay C, et al. The effect on erectile function
    of ¹⁰³palladium implantation for localized prostate cancer. BJU Int. 2005;95:
    847-850.

12. Mabjeesh N, Chen J, Beri A, Stenger A, Matzkin H. Sexual function after permanent 125I-brachytherapy for prostate cancer. Int J Impot Res. 2005;17:96-101.

13. Gontero P, Kirby R. Proerectile pharmacological prophylaxis following nerve-sparing radical prostatectomy (NSRP). Prostate Cancer Prostatic Dis. 2004;7:223-226.

14. Padma-Nathan H, McCullough A, Forest C. Erectile dysfunction secondary to nerve-sparing radical retropubic prostatectomy: comparative phosphodiesterase-5 inhibitor efficacy for therapy and novel prevention strategies. Curr Urol Rep. 2004;5:467-471.

15. Carson CC III, Hubbard JS, Wallen E. Erectile dysfunction and treatment of carcinoma of the prostate. Curr Urol Rep. 2005;6:461-469.

16. Montorsi F, Padma Nathan H, McCullough A, et al. Tadalafil in the treatment of erectile dysfunction following bilateral nerve sparing radical retropubic prostatectomy: a randomized, double-blind, placebo controlled trial. J Urol. 2004;172:1036-1041.

17. McCullough AR. Prevention and management of erectile dysfunction following radical prostatectomy. Urol Clin North Am. 2001;28:613-627.