About Prostate

Understanding what happens when prostate cancer begins to grow also helps explain how each of the different treatment options for prostate cancer is utilized.

Normal Anatomy
The prostate is a small, squishy gland about the size of a walnut that sits under the bladder and in front of the rectum. The urethra, the narrow tube that runs the length of the penis and that carries both urine and semen out of the body, runs directly through the prostate; the rectum, or the lower end of the bowel, sits just behind the prostate and the bladder.

Sitting just above the prostate are the seminal vesicles, two little glands that secrete about 60% of the substances that makes up semen; running alongside and attached to the sides of the prostate are the nerves that control erectile function.

Normal Physiology and Treatment-Related Changes
Despite the best efforts of physicians, treatment strategies for prostate cancer can disrupt normal urinary, bowel, and sexual functioning.

Under normal circumstances, the urinary sphincters, bands of muscle tissue at the base of the bladder and at the base of the prostate, remain tightly shut, thereby preventing urine that is stored in the bladder from leaking out. During urination, the sphincters are relaxed and the urine flows from the bladder through the urethra and out of the body.

During prostatectomy, after the prostate is removed, the bladder is pulled downward and is connected to the urethra at the point where the prostate had sat. If the sphincter at the base of the bladder is damaged during this process, or if it is damaged during radiation therapy, some measure of urinary incontinence or leakage will occur.

Solid waste that is filtered out of the body moves slowly down the intestines, and, under normal circumstances, the resultant stool is excreted through the anus following conscious relaxation of the anal sphincter. Damage to the rectum caused by radiation, or, more rarely, by surgery, can result in a number of bowel problems, including rectal bleeding, diarrhea, or urgency.

If the erectile nerves are damaged during prostatectomy, which was standard during this type of surgery up until the mid 1980s, the ability to achieve erection is lost. Sexual desire is not affected, but severing or otherwise damaging the nerves that stimulate the processes by which erection occurs leads to erectile dysfunction.

Finally, because about 10% of men have what is known as seminal vesicle invasion, meaning that the prostate cancer has either spread into the seminal vesicles or has spread around them, the seminal vesicles are typically removed during prostatectomy and are targeted during radiation therapy. The loss of the prostate and the seminal vesicles renders men infertile. (www.prostatecancerfoundation.org)