Q&A: With UCSF Professor, Tom F. Lue, MD on Impotence/Erectile Dysfunction
Dr. Tom F. Lue is internationally recognized as an expert in the field of managing impotence. Prostate 8 investigators have complied his expertise on this topic…
What are the main causes of impotence/erectile dysfunction (ED)?
There are many potential causes of impotence, which fall within the following categories: psychological, neurogenic, hormonal, vascular, or drug-related.
- Psychological conditions: depression, stress, and anxiety
- Injuries or illnesses that affect the nervous system: Parkinson’s, Alzheimer’s, stroke, head injury, diabetes, and spinal cord injuries
- Pelvic surgery (such as radical prostatectomy) that may injure the cavernous nerves that control erection
- Diseases and conditions that decrease circulating testosterone in the body: castration or hormonal therapy used to treat prostate cancer can decrease libido and impair erections
- Diseases such as high blood pressure, high triglyceride and cholesterol levels, and diabetes mellitus may damage blood vessels and limit the ability to have an erection
- Smoking, alcohol abuse, and some prescription drugs
What happens to sexual function after prostate cancer treatment?
The nerves involved in an erection lie within millimeters behind and on the side of the prostatic capsule. Because of their proximity to the prostate, these nerves may be injured during the radical prostatectomy procedure. This may cause temporary or permanent impotence, although sexual desire and the ability to achieve orgasm should remain. Radiation to the prostate can also damage these nerves.
Can men expect a return of sexual function after surgery or radiation treatment?
The amount of “nerve-sparing” during a prostatectomy procedure influences the likelihood of impotency after treatment. If both nerve bundles are spared, 50–90% of patients — depending on age and health — return to unassisted erectile function over time. When only one nerve bundle is spared, the percentage of patients that return to unassisted erectile function over time is 25–50%. If a non-nerve sparing technique is used, 16% or less of patients will regain full erectile function. Even for men who do recover, return to unassisted sexual function may take six months or more after surgery, and generally continues to improve over two to three years.
For men undergoing radiation the amount and extent of radiation as well as whether or not
they are treated with hormone therapy impacts the likelihood of impotence after treatment.
In patients who had external radiation therapy, ED may occur slowly over months or years.On the other hand, ED after radical prostate surgery occurs within weeks or months but may gradually recover if both nerve bundles are saved.
For men treated with external beam radiation for prostate cancer, 4 to 7 out of every 10 men (40 to 70%) will no longer be able to get or keep an erection. Hormone therapy before or after radiotherapy further increases the risk of erection problems.
For men treated with low dose brachytherapy, research studies show that in men who could have erections before treatment, 15 to 40 out of 100 (15 to 40%) have erection problems after treatment. As with radical prostatectomy, your age is a factor — if you are under 65 when you are treated, impotence is less likely than if you are over 70.
For combined high dose rate brachytherapy and external beam radiotherapy, the statistics on erection problems vary a great deal because the definitions of impotence vary in these studies. Studies report that between 14 and 45 men in every 100 treated (14 to 45%) have some degree of problem, while in older men, up to 76 out of every 100 (76%) had erection problems 7 years after treatment.
Can men overcome impotence? What treatments are available?
Yes, in many cases, impotence can be overcome. Common methods include the following:
Oral Medications: Sildenafil (Viagra), Vardenafil (Levitra), and Tadalafil (Cialis).
Urethral Suppository — MUSE: Prostaglandin E1 (Alprostadil) placed inside the penile urethra and medicated urethral system for erection (MUSE) has been used when oral medications have been unsuccessful. The major advantage of MUSE therapy is that it is applied locally and has few side effects. The major drawbacks are that it may cause moderate penile pain and does not work for everyone.
Penile Injection: When oral medication fails, penile injections to induce erection are another alternative to treat impotence. Refer to the document “Successful Self Penile Injection” found here:http://urology.ucsf.edu/patient-care/cancer/prostate-cancer
Vacuum Erection Device: These devices consist of a plastic cylinder connected to a pump and a constriction ring. A vacuum pump uses either manual or battery power to create suction around the penis and bring blood into it; a constriction device is then released around the base of the penis to keep blood in the penis and maintain the erection.
Penile prosthesis: For men with erectile dysfunction who have failed or cannot tolerate other treatments, a penile prosthesis offers an effective, but more invasive alternative. Prostheses come in either a semi-rigid form or as an inflatable device. Most men prefer the placement of the inflatable penile prosthesis.
Is there any new ED-focused research happening at UCSF?
At UCSF, researchers are studying the potential of using endogenous (one’s own) stem cells to protect nerves and facilitate the recovery of erectile function after radical prostatectomy. Clinic trials are expected in 1–2 years.
Originally published at prost8.blogspot.com on December 2, 2015.