Cancer is a disease in which cells grow in an abnormal way. Normally, the cells divide in a controlled manner. If cells keep dividing when new cells are not needed, a mass of tissue called a tumor forms.

A tumor can be benign or malignant. A benign tumor is not cancer and will not spread to other parts of the body. A malignant tumor is cancer. Cancer cells invade and damage tissue around them. They can also enter the lymph and blood streams, spreading to other parts of the body. Prostate cancer is the development of malignant cells in the prostate gland.

Normal Anatomy and the Development of Prostate Cancer

The prostate gland is located in the pelvic region, under the bladder and adjacent to the rectum. The prostate gland surrounds the urethra, the tube that carries urine outside the body from the bladder. It makes and stores seminal fluid, which is needed to keep sperm healthy. During ejaculation, the prostate releases the seminal fluid into the urethra where it combines with sperm to make semen.

Normal Male Anatomy

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Cell division and cell death are a normal process in the body to replace old or damaged cells. Male hormones are needed for the prostate to function normally and help it remain its normal size. As men age, the prostate changes and grows, and hormone levels decrease. These influences may cause changes in the cells that can lead to prostate cancer.

Prostate cancer is one of the most common types of cancer in men. According to the National Cancer Institute, an estimated 220,800 American men will be diagnosed with prostate cancer in 2015, resulting in an estimated 27,540 deaths.