Overview
Prostate cancer starts in the prostate, a small walnut-shaped gland in men, surrounds the urethra. This gland sits below the bladder and just in front of the rectum. The prostate and the two glands above it, the seminal vesicles, produce the seminal fluid that surrounds sperm during ejaculation.
Like other types of cancer, prostate cancer occurs when the DNA within the cells of the prostate mutates, and the cells begin to divide rapidly. Prostate cancer is the most common form of cancer among men in the United States and the second leading cause of cancer deaths in men. Around 250,000 men will be diagnosed with prostate cancer this year. One in nine men will develop some form of prostate cancer in their lifetime, but only about one in 41 of those diagnosed will die from it. The average age at diagnosis is 66.
The prostate can develop growths or tumors that are benign or malignant. Some can grow quickly, but most tumors or cancer in the prostate grow slowly over time. If the cancer is diagnosed early and treatment is begun, survival rates are usually high. Many men have some form of prostate cancer in their lifetime but are not aware of it, as there are no symptoms or side effects.
The prostate can also increase in size as men age and cause problems that are unrelated to cancer, such as difficulty urinating or sexual dysfunction. This condition is called benign prostatic hyperplasia. Often, the prostate can develop cancer that grows so slowly that it will not affect a man in his lifetime.
When cancer does develop, it’s almost always adenocarcinoma, a type of cancer that develops in the glands. Other possible types of prostate cancer can include:
- Sarcoma
- Small cell carcinoma
- Neuroendocrine tumors
- Transitional cell carcinoma
These types are relatively rare.
Symptoms
Symptoms of prostate cancer can include the following:
- Difficulty urinating
- Urinary incontinence
- Erectile dysfunction
- Pain in the lower pelvis
- Painful ejaculation
- Blood in the urine or semen
- Frequent urination
- Loss of appetite
- Weight loss
- Bone pain
- Edema (swelling of legs and feet)
Causes
As with other forms of cancer, the cause of prostate cancer is largely unknown. There are several risk factors that can increase the chance of contracting prostate cancer, but the mechanisms that cause it require further study.
Cancer forms when the DNA in the cells of the prostate mutate, either through an inherited or acquired mutation.
Risk Factors
There are myriad risk factors for prostate cancer, such as:
- Prostate cancer is rarely found in men under 50. Older men are more likely to develop prostate cancer than younger men.
- Family history of the disease. If your parent or siblings develop prostate cancer, you have double the chances of developing cancer yourself. However, most prostate cancer appears in men who have no family history of the disease.
- For reasons that are still unclear, prostate cancer is more common among African American men and Caribbean men of African descent than Asian American, Hispanic, or white men.
- Men in North America, northwestern Europe, Australia, and the Caribbean islands have a higher chance of developing prostate cancer than men in Africa, Asia, Central America, and South America. The increase in testing in developed countries certainly affects this statistic but doesn’t totally account for the increase in prevalence. Interestingly, Asian American men have a lower chance of developing the disease than white men but have a higher chance than men of similar ethnic backgrounds in Asia.
- Lifestyle factors can increase the chance of prostate cancer, though it’s still unclear why. Diets high in sugars, animal fats, and dairy have been shown to increase risk.
- Smoking cigarettes is known to increase the risk of several types of cancer, including prostate cancer.
- Prostate inflammation. Some studies have shown a link between prostatitis, or inflammation of the prostate, and prostate cancer, but the link requires further study.
Survival Rates
The survival rate for most forms of prostate cancer is high. According to the SEER database maintained by the National Cancer Institute, the five-year relative survival rate for prostate cancer is around 98%.
SEER stands for Surveillance, Epidemiology, and End Results. The database tracks three stages of prostate cancer:
- Local: Cancer has not spread outside the prostate.
- Regional: Cancer has spread outside the prostate to nearby organs or lymph nodes.
- Distant: Cancer has metastasized and spread to bones, organs, and the brain.
The five-year relative survival rate for the local and regional stages of prostate cancer is close to 100%, and the survival rate for the distant stage is 30%.
Diagnosing prostate cancer is usually done with two tests: the digital rectal examination (DRE) and the prostate-specific antigen (PSA) test.
During a DRE, a physician will insert a gloved, lubricated finger into your rectum to feel for any abnormalities on the prostate. If the prostate feels enlarged or abnormal, your doctor may schedule a PSA test to check for signs of cancer in the bloodstream.
A PSA test checks for antigens in the blood that are specific to the prostate and prostate cancer. A high PSA level usually indicates a problem with the prostate, though not always.
Abnormalities in the prostate or a high PSA may mean scheduling a biopsy to remove part of the prostate and examine the cells under a microscope to check for signs of cancer. Your doctor may also request an imaging scan, such as a CT scan, to see if the cancer has spread to other parts of the body.
There are many treatment options available if cancer is discovered in the prostate, including the following:
- Surgery
- Chemotherapy
- Radiation therapy
- Cryotherapy
- Hormonal therapy
- Immunotherapy