What is Prostate Cancer?
Anatomy of the male pelvis, genitals, and urinary tract
The prostate is a glandular organ, which a part of the male reproductive system. It is often described as the same size of a walnut, normally about 3 cm long (slightly more than 1 inch); it weighs about 30 g (1 ounce) and is located at the neck of the bladder and in front of the rectum.
The prostate surrounds the urethra, which is a tubular structure that carries the urine (produced by the kidney and stored in the bladder) out of the penis during voiding, and the sperm (produced in the testicle) during ejaculation.
In addition, during ejaculation a thin, milky fluid produced by the prostate is added to the mix. This ejaculate that also includes fluid from the seminal vesicles, constitutes the male semen.
In prostate cancer, normal cells undergo a transformation in which they not only grow and multiply without normal controls, but they also change in their microscopic appearance and can invade adjacent tissues. Prostate cancer cells form into malignant tumors or masses, which then overwhelm surrounding tissues by invading their space and taking vital oxygen and nutrients.
Cancer cells from these tumors can eventually invade remote organs via the bloodstream and the lymphatic system.This process of invading and spreading to other organs is called metastasis. Common metastatic locations where prostate cancer cells may eventually be found include pelvic lymph nodes, and bones. The lungs and the liver may also show deposits of, or metastases from, prostate cancer, but that is less common.
Almost all prostate cancers arise from the glandular cells in the prostate. Cancer arising from a glandular cell in any organ in the body is known as adenocarcinoma. Therefore, the most common type of prostate cancer is an adenocarcinoma. The most common non-adenocarcinoma is transitional cell carcinoma. Other rare types include small cell carcinoma and sarcoma of the prostate.
Older men commonly have an enlarged prostate, caused by a benign (noncancerous) condition called benign prostatic hyperplasia (BPH). Prostate gland cells simply keep growing in number in the prostate gland in BPH. BPH can cause urinary symptoms but is not a form of prostate cancer (see BPH).
In the U.S., prostate cancer is the most common cancer in men and is the second leading cause of cancer death in men (the first being lung cancer). One man in 7 will be diagnosed with prostate cancer in their lifetime. In many cases it can be a slow moving disease and does not result in death before other natural causes. Only one man in 39 will die of prostate cancer. Some 180,000 new cases of prostate cancer are projected this year and there will be 26,000 deaths due to prostate cancer this year.
This low death rate also suggests that increased public awareness with earlier detection and treatment has begun to affect mortality from this prevalent cancer.
Prostate cancer has seemed to increase in frequency, due in part to the widespread availability of serum prostate specific antigen (PSA) testing. However, the death rate from this disease has shown a steady decline, and currently more than 2 million men in the U.S. are still alive after being diagnosed with prostate cancer at some point in their lives.
The estimated lifetime risk of being diagnosed with the disease is 17.6% for Caucasians and 20.6% for African Americans. The lifetime risk of death from prostate cancer similarly is 2.8% and 4.7%, respectively. Because of these numbers, prostate cancer is likely to impact the lives of a significant proportion of men that are alive today.