Prostate Cancer

What is the prostate gland?

The prostate gland is an organ that is located at the base or outlet (neck) of the urinary bladder. (See the diagram that follows.) The gland surrounds the first part of the urethra. The urethra is the passage through which urine drains from the bladder to exit from the penis. One function of the prostate gland is to help control urination by pressing directly against the part of the urethra that it surrounds. The main function of the prostate gland is to produce some of the substances that are found in normal semen, such as minerals and sugar. Semen is the fluid that transports the sperm to assist with reproduction. A man can manage quite well, however, without his prostate gland. (See the section on surgical treatment for prostate cancer.)

In a young man, the normal prostate gland is the size of a walnut (<30g). During normal aging, however, the gland usually grows larger. This hormone-related enlargement with aging is called benign prostatic hyperplasia (BPH), but this condition is not associated with prostate cancer. Both BPH and prostate cancer, however, can cause similar problems in older men. For example, an enlarged prostate gland can squeeze or impinge on the outlet of the bladder or the urethra, leading to difficulty with urination. The resulting symptoms commonly include slowing of the urinary stream and urinating more frequently, particularly at night. Patients should seek medical advice from their urologist or primary-care physician if these symptoms are present.

What is prostate cancer?

Prostate cancer is a malignant (cancerous) tumor (growth) that consists of cells from the prostate gland. Generally, the tumor usually grows slowly and remains confined to the gland for many years. During this time, the tumor produces little or no symptoms or outward signs (abnormalities on physical examination). However, all prostate cancers do not behave similarly. Some aggressive types of prostate cancer grow and spread more rapidly than others and can cause a significant shortening of life expectancy in men affected by them. A measure of prostate cancer aggressiveness is the Gleason score (discussed in more detail later in this article), which is calculated by a trained pathologist observing prostate biopsy specimens under the microscope.

As the cancer advances, however, it can spread beyond the prostate into the surrounding tissues (local spread). Moreover, the cancer also can metastasize (spread even farther) throughout other areas of the body, such as the bones, lungs, and liver. Symptoms and signs, therefore, are more often associated with advanced prostate cancer.

Why is prostate cancer important?

Prostate cancer is the most common malignancy in American men and the second leading cause of deaths from cancer, after lung cancer. According to the American Cancer Society's most recent estimates, 192,280 new cases of prostate cancer would be diagnosed in 2009 and 27,360 would die from the disease.

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. As reflected in these numbers, prostate cancer is likely to impact the lives of a significant proportion of men that are alive today.

Over the years, 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.

Although it is subject to some controversy, many experts in this field, therefore, recommend that beginning at age 40, all men should undergo screening for prostate cancer.