Types Nearly all prostate cancer arises from the glands of the prostate. Glandular cancer (adenocarcinoma) accounts for 95 percent of all prostate cancer cases. Over half of these cancers develop from the rear (posterior) portion of the prostate that lies closest to the rectum, which is why rectal examination is useful to detect the tumor .
Other types are rare. Most, including leiomyosarcoma and rhabdomyosarcoma, arise from supporting or connective tissues within or around the prostate. Others develop in the ducts within the prostate. Tumors can also spread to the prostate from other locations such as the bladder or adrenal gland.
Some types are not actually cancer but have characteristics that appear precancerous . These are called prostatic intraepithelial neoplasia (PIN), a term referring to cell growths that are almost active cancers or may soon become cancer. Men with PIN have to be observed closely and have periodic biopsies.
How It Spreads Prostatic cancers spread through the lymphatic system to pelvic lymph nodes and through the bloodstream to bones and other tissues. The earliest spread is usually detected in lymph nodes in the pelvis near the prostate. Other areas of spread are to lymph nodes around the arteries and veins leading to the legs and pelvic organs and to bones in the spine, legs, arms and hips. Ultimately, it can reach almost any organ in the body. The tumor may also spread directly through the prostate to surrounding tissues or may grow inward, blocking the flow of urine.
