The prostate is part of a man's reproductive system. It's an organ located in front of the rectum and under the bladder. The prostate surrounds the urethra, the tube through which urine flows.
A healthy prostate is about the size of a walnut. If the prostate grows too large, it squeezes the urethra. This may slow or stop the flow of urine from the bladder to the penis.
The prostate is a gland. It makes part of the seminal fluid. During ejaculation, the seminal fluid helps carry sperm out of the man's body as part of semen.
Male hormones (androgens) make the prostate grow. The testicles are the main source of male hormones, including testosterone. The adrenal gland also makes testosterone, but in small amounts.
Cancer begins in cells, the building blocks that make up tissues. Tissues make up the organs of the body.
Normal cells grow and divide to form new cells as the body needs them. When normal cells grow old or get damaged, they die, and new cells take their place.
Sometimes, this process goes wrong. New cells form when the body doesn't need them, and old or damaged cells don't die as they should. The buildup of extra cells often forms a mass of tissue called a growth or tumor.
Prostate growths can be benign (not cancer) or malignant (cancer).
Benign growths are not as harmful as malignant growths:
Benign growths (such as BPH):
- are rarely a threat to life
- can be removed and probably won't grow back
- don't invade the tissues around them
- don't spread to other parts of the body
- may be a threat to life
- often can be removed, but sometimes grow back
- can invade and damage nearby tissues and organs
- can spread to other parts of the body
Cancer cells can spread by breaking away from the prostate tumor. They enter blood vessels or lymph vessels, which branch into all the tissues of the body. The cancer cells can attach to other tissues and grow to form new tumors that may damage those tissues. The spread of cancer is called metastasis.
When you're told you have prostate cancer, it's natural to wonder what may have caused the disease. But no one knows the exact causes of prostate cancer. Doctors seldom know why one man develops prostate cancer and another doesn't.
However, research has shown that men with certain risk factors are more likely than others to develop prostate cancer. A risk factor is something that may increase the chance of getting a disease.
Studies have found the following risk factors for prostate cancer:
- Age over 65: Age is the main risk factor for prostate cancer. The chance of getting prostate cancer increases as you get older. In the United States, most men with prostate cancer are over 65. This disease is rare in men under 45.
- Family history: Your risk is higher if your father, brother, or son had prostate cancer.
- Race: Prostate cancer is more common among black men than white or Hispanic/Latino men. It's less common among Asian/Pacific Islander and American Indian/Alaska Native men.
- Certain prostate changes: Men with cells called high-grade prostatic intraepithelial neoplasia (PIN) may be at increased risk of prostate cancer. These prostate cells look abnormal under a microscope.
- Certain genome changes: Researchers have found specific regions on certain chromosomes that are linked to the risk of prostate cancer. According to recent studies, if a man has a genetic change in one or more of these regions, the risk of prostate cancer may be increased. The risk increases with the number of genetic changes that are found. Also, other studies have shown an elevated risk of prostate cancer among men with changes in certain genes, such as BRCA1 and BRCA2.
Having a risk factor doesn't mean that a man will develop prostate cancer. Most men who have risk factors never develop the disease.
Many other possible risk factors are under study. For example, researchers have studied whether vasectomy (surgery to cut or tie off the tubes that carry sperm out of the testicles) may pose a risk, but most studies have found no increased risk. Also, most studies have shown that the chance of getting prostate cancer is not increased by tobacco or alcohol use, BPH, a sexually transmitted disease, obesity, a lack of exercise, or a diet high in animal fat or meat. Researchers continue to study these and other possible risk factors.
Researchers are also studying how prostate cancer may be prevented. For example, they are studying the possible benefits of certain drugs, vitamin E, selenium, green tea extract, and other substances. These studies are with men who have not yet developed prostate cancer.
A man with prostate cancer may not have any symptoms. For men who do have symptoms, the common symptoms include:
- Urinary problems
- Not being able to pass urine
- Having a hard time starting or stopping the urine flow
- Needing to urinate often, especially at night
- Weak flow of urine
- Urine flow that starts and stops
- Pain or burning during urination
- Difficulty having an erection
- Blood in the urine or semen
- Frequent pain in the lower back, hips, or upper thighs
Most often, these symptoms are not due to cancer. BPH, an infection, or another health problem may cause them. If you have any of these symptoms, you should tell your doctor so that problems can be diagnosed and treated.