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Prostate Cancer
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Coping with Prostate Cancer

 

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Prostate Cancer Treatment and Impotence

Many men when confronted with a diagnosis of prostate cancer worry about their sexuality almost as much as they do about their health. Prostate cancer treatments can cause impotence, however, the continual refinement in both techniques and technologies for prostate cancer treatment and impotence treatment are helping to reduce the occurrence of impotence. There is sex after prostate cancer and there are many tools to help patients engage in sex after prostate cancer. Read on to find out about the physiological and chemical reactions that produce erection. By learning about what causes an erection, you will better be able to select the proper method for coping with impotence.


Physiological Cause of Erection
Most people know that erections are caused by the flow of blood into the three chambers of the penis. The corpora cavernosa are two columns of spongy tissue that make up 90 percent of the erectile tissue of the penis. The corpus spongiosum surround the urethra and holds only about 10 percent of the blood present in the penis during erection.

During arousal, the smooth muscles lining the veins of the arteries begin to relax. This relaxation causes blood to flow in. The veins of the penis begin to constrict; thus, blood can get in much more easily then it can out. The penis can hold 10 times the amount of blood when it is erect as opposed to when it is not erect. After orgasm, the veins and arteries return to normal and the blood flow returns to normal. Prostate cancer treatments can affect the flow of blood into the penis. Prostatectomy has been known to divert the flow of blood into the penis while radiation treatment has been known to cause arteriosclerosis, which is the hardening of the arteries.

Chemical Causes of Erection
An erection begins with arousal. The brain detects the body becoming sexually aroused and transmits a message along the NANC neuron to tell the body to begin creating an erection. NANC stands of nonadrenergic, noncholinergic and uses nitric oxide to transmit the message. Once the nitric oxide reaches the neurovascular nerve bundles that hug the prostate gland, an enzyme called guanosine cyclase is released. An enzyme is like a biological catalyst; it is a specially folded protein that fits only into one substrate, like a key fits into only one lock. A substrate is the compound that the enzyme will change.

The substrate for guanylate cyclase is called GTP or guanosine triphosphate. The guanosine cyclase changes the GTP into cGMP. cGMP causes the smooth muscles lining the arterial walls of the penis to relax. cGMP, however, is broken down by a second enzyme called phosphodiesterase type 5 or PDE 5. PDE 5 turns cGMP back into guanosine triphosphate or GTP to cause the arterial walls to not relax and decreasing the blood flow into the penis.

The chemical cycle is started by the introduction of nitric oxide. The cycle begins with enzyme guanosine cyclase changing GTP into cGMP. The enzyme finishes when enzyme PDE 5 turns cGMP back into GTP.

Causes of Impotence
Both blood and nerves are necessary in producing erection. Any prostate cancer treatment that upsets the pathways to the penis can result in impotence. Radiation therapy can impede the flow of blood to the penis by arteriosclerosis. Prostatectomy can result in a diversion of the blood flow. Both of these forms of impotence may be helped by the use of a PDE 5 inhibitor which prevents normal PDE 5 from breaking down cGMP. Examples of oral PDE 5 inhibitors are sildenafil, varendafil, and tadalafil which are trademarked respectively as Viagra, Levitra, and Cialis.

PDE 5 inhibitors will not be helpful for men who experience impotence due to a prostate cancer treatment that has damaged the neurovascular bundles that are attached to the NANC. Without the presence of nitrous oxide, the chemical cycle never begins. Cryotherapy and radical prostatectomy without nerve-sparing destroys or removes these nerve bundles. Men for whom PDE 5 inhibitors are ineffective or men who cannot take PDE 5 inhibitors may want to consider other types of treatments for impotence such as penile implants or the vacuum erection device.

 
 

Mechanics of Erection
Oral Drugs for Impotence
Penile Implants for Impotence
Vacuum Erection Devices for Impotence
Penile Injections
Urethral Suppositories for Impotence
Sex Therapy

 

 
 
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