Prostate cancer is the most common cancer after skin cancer in men in the United States. The disease may be slow growing or, in some cases, very aggressive. Many newer treatments allow men with prostate cancer to live active, productive lives.
What Is Prostate Cancer?
Prostate cancer starts in the prostate, a gland located below the bladder and in front of the rectum. While the exact cause of prostate cancer is unknown, generally speaking it results from mutations in cell DNA. DNA is the chemical that makes up your genes, which control when your cells grow, divide into new cells, and die. DNA mutations that turn on oncogenes (which help cells grow and divide) or that turn off tumor-suppressor genes (which slow cell division or make cells die when they should) can cause prostate cells to grow abnormally and lead to cancer.
The prostate contains several types of cells, but nearly all prostate cancers develop from glandular cells, which make fluid that becomes part of semen. Cancers that start in glandular cells are known as adenocarcinomas.
All prostate cancers do not behave the same. In some men, prostate cancer is a slow-growing disease that is unlikely to cause serious problems. In others, however, the disease is very aggressive and requires treatment.
Prostate cancer cells can spread by invading nearby organs and tissues, such as the bladder or rectum, or by traveling through the blood or lymph to other parts of the body. This is known as metastatic prostate cancer. Other than the lymph nodes near the prostate, the most common site of prostate cancer spread, or metastasis, is the bones, especially in the spine. In some cases, prostate cancer has already metastasized by the time a man learns he has the disease. Also, prostate cancer can recur several years after initial treatment.
Many doctors used to consider prostate cancer in older men to be just part of the normal aging process, and the disease was largely ignored, except when it struck younger men. Now there are newer, better treatments for prostate cancer, and many men who have or had prostate cancer at any age are leading active, productive lives.
Understanding the Prostate
The prostate makes and stores seminal fluid—a milky liquid that protects and nourishes sperm. The prostate surrounds part of the urethra, the tube that carries urine and semen out of the body.
If the prostate, which is normally about the size of a walnut, grows too large, it can slow or block the flow of urine. Many men develop a noncancerous condition called benign prostatic hyperplasia (BPH), or enlargement of the prostate. BPH typically develops in the zone of the prostate that surrounds the urethra (transition zone). For this reason BPH may cause difficulty with urination. BPH does not lead to or increase the chance of prostate cancer.
Most prostate cancer develops in the zone of the prostate near the rectum (peripheral zone), which is why a digital rectal exam is a useful screening test—and why prostate cancer typically does not interfere with urination as much as BPH does. Even so, because the prostate is close to the urethra and several other important structures, prostate cancer and its treatment can disrupt normal urinary, bowel, and sexual function.
How Common Is Prostate Cancer?
The American Cancer Society estimated that approximately 233,000 new cases of prostate cancer would be diagnosed and nearly 30,000 men would die of the disease in 2014. Prostate cancer is the second leading cause of cancer death, behind lung cancer, in men in the United States.
The incidence of prostate cancer has nearly doubled over the past 20 years. One possible reason is that, due to a decline in deaths from heart disease, more men are living longer, reaching ages at which the risk of prostate cancer is highest. More than 75 percent of prostate cancers are found in men over age 65.
Early Detection & Prevention
Due to prostate-specific antigen (PSA) screening—which may detect prostate cancer early—as well as improvements in therapy, deaths from prostate cancer have decreased dramatically (40 to 50 percent) since the early 1990s. Screening alone is credited for one-third of the decrease. While there is no perfect test for prostate cancer, PSA screening is the best indicator available.
Ultimately, decisions about screening should be individualized based on a man’s level of risk, overall health, and life expectancy, as well as his desire for eventual treatment if he is diagnosed with prostate cancer. Learn more about detecting and preventing prostate cancer.