Prostate Cancer

Approved by the Cancer.Net Editorial Board, 12/2022

The prostate is a walnut-sized gland located behind the base of the penis, in front of the rectum, and below the bladder. It surrounds the urethra, the tube-like channel that carries urine and semen through the penis. The prostate’s main function is to make seminal fluid, the liquid in semen that protects, supports, and helps transport sperm.

The prostate continues to enlarge as people age. This can lead to a condition called benign prostatic hypertrophy (BPH), which is when the urethra becomes blocked. BPH is a common condition associated with growing older, and it has not been associated with a greater risk of having prostate cancer.

Cancer begins when healthy cells in the prostate change and grow out of control, forming a tumor. A tumor can be cancerous or benign. A cancerous tumor is malignant, meaning it can grow and spread to other parts of the body. A benign tumor means the tumor can grow but will not spread.

Prostate cancer is somewhat unusual when compared with other types of cancer. This is because many prostate tumors do not spread quickly to other parts of the body. Some prostate cancers grow very slowly and may not cause symptoms or problems for years or ever. Even when prostate cancer has spread to other parts of the body, it often can be managed with treatment for a long time. So people with prostate cancer, and even those with advanced prostate cancer, may live with good health and quality of life for many years. However, if the cancer cannot be well controlled with existing treatments, it can cause symptoms like pain and fatigue and can sometimes lead to death. An important part of managing prostate cancer is watching for growth over time to find out if it is growing slowly or quickly. Based on the pattern of growth, your doctor can decide the best available treatment options and when to give them.

Histology is how cancer cells look under a microscope. The most common histology found in prostate cancer is called adenocarcinoma. Other, less common histologic types, called variants, include neuroendocrine prostate cancer and small cell prostate cancer. These variants tend to be more aggressive, produce much less prostate-specific antigen (PSA), and spread outside the prostate earlier. Read more about neuroendocrine tumors.

Prostate-specific antigen (PSA) is a protein produced by cells in the prostate gland and released into the bloodstream. PSA levels are measured using a blood test. Although there is no such thing as a “normal PSA” for anyone at any given age, a higher-than-normal level of PSA can be found in people with prostate cancer. Other non-cancerous prostate conditions, such as BPH (see above) or prostatitis can also lead to an elevated PSA level. Prostatitis is the inflammation or infection of the prostate. In addition, some activities like ejaculation can temporarily increase PSA levels. Ejaculations should be avoided before a PSA test to avoid falsely elevated tests. People should discuss with their primary care doctor the pros and cons of PSA testing before using it to screen for prostate cancer. See the Screening section for more information.