What You Should Know About Erectile Dysfunction After Prostate Cancer
Regardless of whether the nerves were spared during surgery or whether the most precise dose planning was used during radiation therapy, nearly all men will experience some erectile dysfunction for the first few months after treatment. The reason for this is simple: the nerves and blood vessels that control the physical aspect of an erection are incredibly delicate, and any trauma to the area will result in changes to the natural order. However, within one year after treatment, nearly all men with intact nerves will see a substantial improvement. By this point, about 40 to 50 percent of men who undergo nerve-sparing prostatectomy will have returned to their pre-treatment function; after two years, about 30 to 60 percent will have returned to pre-treatment function. These rates vary widely depending on the surgeon and level of experience and how outcomes are reported (i.e., whether a study measures a doctor’s opinion of a patient’s sexual function or whether the survey actually asks the patient about this side effect).
For those who underwent radiation therapy, the numbers are better but tend not to improve too much over time. About 25 to 50 percent of men who undergo brachytherapy will experience erectile dysfunction, versus nearly 50 percent of men who have standard external beam radiation; after two to three years, few men will see much of an improvement, and occasionally these numbers worsen over time given that radiation takes longer to have effects.
Men who undergo procedures that are not designed to minimize side effects or those whose treatments are administered by physicians who are not proficient in the procedures will fare worse. In addition, men with other diseases or disorders that impair their ability to maintain an erection, such as diabetes or vascular problems, will have a more difficult time returning to pre-treatment function.
Within one year after treatment, nearly all men with intact nerves will see a substantial improvement.
Management of Erectile Dysfunction
When a man is sexually aroused, the erectile nerves running alongside the penis stimulate the muscles to relax, allowing blood to rush in. At the same time, tiny valves at the base of the penis lock shut, preventing the blood from flowing back out and therefore causing the penis to stay rigid.
The oral medications for erectile dysfunction, sildenafil (Viagra®), tadalafil (Cialis®), and vardenafil (Levitra®), relax the muscles in the penis, allowing blood to rapidly flow in. On average, the drugs take about an hour to begin working; the erection-helping effects of sildenafil and vardenafil last for about 8 hours and tadalafil about 36 hours. About 75 percent of men who undergo nerve-sparing prostatectomy or more precise forms of radiation therapy have reported successfully achieving erections after using these drugs.
However, these drugs are not for everyone. Many men with angina or other heart problems take medications that contain nitrates to help the blood flow better to the heart. All three agents used for erectile dysfunction can affect the way that the nitrates work – and cause blood pressure to drop to dangerously low levels. They can also interfere with alpha-blockers, drugs that are commonly used in men with the noncancerous growth of the prostate known as BPH and that are often used in men following certain types of radiotherapy, particularly brachytherapy. In addition to the oral medications, there are a number of alternative treatments that might be helpful to men with erectile dysfunction.
MUSE is a medicated pellet about half the size of a grain of rice that is inserted into the urethra through the opening at the tip of the penis using a disposable plastic applicator. Like the oral medications, it, too, stimulates blood flow into the penis; an erection typically occurs within 10 minutes after insertion of the pellet and can last for 30 to 60 minutes. About 40 percent of men have reported successfully achieving erections after using this drug, but the results are often inconsistent.
Caverject uses the same drug that is in the MUSE pellets, but delivers it via an injection directly into the penis. It takes about 10 minutes to work and lasts for about 30 minutes. Although nearly 90 percent of men using Caverject reported erections about six months after therapy, most men are not willing to inject themselves regularly, so the treatment is not often used for long periods of time.
For those unwilling or unable to use any form of medication to help improve erectile function, there are still a number of choices.
The vacuum constriction device, or vacuum pump, creates an erection mechanically, by forcing blood into the penis using a vacuum seal. Because the blood starts to flow back out once the vacuum seal is broken, a rubber ring is rolled onto the base of the penis, constricting it sufficiently so that the blood does not escape. About 80 percent of men find this device successful, but it, too, has a high dropout rate.
Note that the constriction ring at the base of the penis is effectively cutting off fresh circulation. Because of this effect, it is crucial that the ring be removed immediately after intercourse, or the tissue can be damaged due to lack of flowing oxygen.
The final option for treating erectile dysfunction is the surgically inserted penile implant. With the three-piece implant, a narrow flexible plastic tube is inserted along the length of the penis, a small balloon-like structure filled with fluid is attached to the abdominal wall, and a release button is inserted into the testicle. The penis remains flaccid until an erection is desired, at which point the release button is pressed and fluid from the balloon rushes into the plastic tube. As the tube straightens from being filled with the fluid, it pulls the penis up with it, creating an erection. Assuming the mechanics are working correctly, it is, by definition, 100 percent effective, and about 70 percent of men remain satisfied with their implants even after 10 years. Note that the surgical procedure is done under general anesthesia, so this option is not available to men who are not considered good candidates for surgery because of other health reasons.
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