Prostate cancer is cancer that starts in the prostate gland. The prostate is a small, walnut-sized structure that makes up part of a man's reproductive system. It wraps around the urethra, the tube that carries urine out of the body.
Causes, incidence, and risk factors
Prostate cancer is the third most common cause of death from cancer in men of all ages and is the most common cause of death from cancer in men over age 75. Prostate cancer is rarely found in men younger than 40.
People who are at higher risk include:
- African-American men, who are also likely to develop cancer at every age
- Men who are older than 60
- Men who have a father or brother with prostate cancer
Other people at risk include:
- Men exposed to agent orange exposure
- Men who abuse alcohol
- Men who eat a diet high in fat, especially animal fat
- Tire plant workers
- Men who have been exposed to cadmium
A common problem in almost all men as they grow older is an enlarged prostate (benign prostatic hyperplasia, or BPH). This problem does not raise your risk of prostate cancer.
The PSA blood test is often done to screen men for prostate cancer. Because of PSA testing, most prostate cancers are now found before they cause any symptoms.
The symptoms listed below can occur with prostate cancer (Most of the time these symptoms are caused by other prostate problems that are not cancer):
- Delayed or slowed start of urinary stream
- Dribbling or leakage of urine, most often after urinating
- Slow urinary stream
- Straining when urinating, or not being able to empty out all of the urine
- Blood in the urine or semen
- Bone pain or tenderness, most often in the lower back and pelvic bones (only when the cancer has spread)
Signs and tests
Prostate biopsy is the only test that can confirm the diagnosis. Tissue from the prostate is viewed underneath a microscope. Biopsy results are reported using something called a Gleason grade and a Gleason score.
The Gleason grade is how aggressive the prostate cancer might be. It grades tumors on a scale of 1 - 5, based on how different from normal tissue the cells are. Often, more than one Gleason grade is present within the same tissue sample. The Gleason grade is therefore used to create a Gleason score by adding the two most predominant grades together (a scale of 2 - 10). The higher the Gleason score, the more likely the cancer is to have spread beyond the prostate gland:
Scores 2 - 4: Low-grade cancer
Scores 5 - 7: Intermediate-grade cancer. Most prostate cancers fall into this category.
Scores 8 - 10: High-grade cancer (poorly-differentiated cells)