Prostate cancer at a glance
- Prostate cancer occurs in a man’s prostate, the small gland that produces seminal fluid that conveys sperm during ejaculation.
- Prostate cancer is the second most common cancer among men in the United States.
- Most prostate cancer is detected in very early stages, when the prognosis for successful treatment is good.
- Prostate cancer is categorized into four stages, with stage I being microscopic and stage IV having spread from the prostate to other organs.
- Stage and grade dictates the type of treatment, ranging from no treatment to removal of the prostate (prostatectomy).
What is prostate cancer?
The prostate is part of the male reproductive system. The prostate gland is small, about the size of a walnut. It produces semen, the fluid that nourishes and carries sperm.
Prostate cancer is the second most common cancer among men in the U.S. According to an estimate from the American Cancer Society, there will be about 174,650 new cases of prostate cancer diagnosed in the U.S. in 2019.
Many men age 50 and older have some trace of prostate cancer. Fortunately, prostate cancer often grows very slowly. When it is detected early, before it has grown beyond the prostate gland, doctors can effectively treat prostate cancer.
A prostate cancer diagnosis is classified according the stage of the cancer. This “staging” relates to where the cancer is in the prostate or outside it.
- Stage I: The tumor is microscopic. The doctor cannot feel it, but the prostate-specific antigen (PSA) level that indicates potential cancer is elevated.
- Stage II: The tumor is limited to within the prostate.
- Stage III: The tumor extends outside the prostate.
- Stage IV: Cancer has spread to other organs.
More than 90 percent of prostate cancers are detected while they are at stage I, II or III.
Causes of prostate cancer
Like other cancers, prostate cancer develops when some cells in the prostate mutate or become abnormal. These cells grow and divide faster than normal cells, forming a tumor. Some cancer cells might metastasize, or spread to other parts of the body.
The exact cause of prostate cancer is unknown. However, researchers have identified certain risk factors for prostate cancer including:
- Being older than age 50. The risk of prostate cancer increases with age; about 80 percent of prostate cancer occurs in men older than age 65.
- Living in North America and Northern Europe. Prostate cancer occurs more frequently in these areas than in other parts of the world.
- Being of African-American heritage. African-American men are more likely to get prostate cancer, and their death rate from prostate cancer is higher.
- Having a family history of prostate cancer or breast cancer.
- Being obese. Research has linked obesity and increased risk of death from prostate cancer.
- Eating a diet high in fat and/or red meat. Studies suggesting this risk factor may not be definitive, but men who eat a diet higher in fat appear to have more risk of prostate cancer. A fattier diet also might raise the levels of hormones that cause prostate cancer to grow faster.
Symptoms of prostate cancer
Many men who have prostate cancer are unaware they have it. Prostate cancer usually grows very slowly and might not cause symptoms at first. Prostate enlargement and prostate cancer often share similar symptoms. It is important to be aware of the symptoms in order to seek a prompt medical evaluation. The cancer can be very dangerous if it spreads outside the prostate or begins to grow faster.
Prostate cancer that is growing might cause symptoms such as:
- Needing to urinate often, especially at night
- Weaker stream of urine or trouble urinating
- Difficulty starting or stopping urine
- Pain or burning during urination or ejaculation
- Blood in urine or semen
- Inability to urinate standing up
- Leaking urine when you laugh or cough
- Pelvic pain or discomfort
- Erectile dysfunction
Advanced prostate cancer, or stage IV prostate cancer that has spread to other parts of the body, might cause additional symptoms such as:
- Pain in the bones of the pelvis or lower body
- Dull, deep pain or stiffness in the pelvis or upper thighs, lower back or ribs
- Losing weight or reduced appetite
- Fatigue, nausea, vomiting or constipation
- Swelling of the legs and feet
- A sense of weakness, or even paralysis, in the legs (constipation sometimes accompanies this weakness).
Men who experience any of these symptoms should contact their doctor.
Diagnosis of prostate cancer
Experts continually debate how and how frequently doctors should screen men for prostate cancer. Medical organizations are still reviewing which patients benefit most from screening and treatment for this disease.
Screening and diagnosis can have their own risks. These include false-negatives, false positives and “over diagnosis,” meaning a cancer that would never have caused any problem is detected and treated, unnecessarily placing the patient at risk from radiation or surgery. Physicians help each patient determine whether screening makes sense for him.
Doctors screen men for prostate cancer in two primary ways:
- Prostate-specific antigen (PSA) test. A laboratory examines a blood sample for PSA. If the level of PSA is higher than normal, it could indicate a problem with the prostate.
- Digital rectal exam (DRE). A DRE is a manual exam in which the doctor inserts a gloved finger into the rectum to feel the prostate. Because the prostate is next to the rectum, the doctor can note anything unusual.
Doctors cannot feel very small tumors. For that reason, a PSA test is more reliable for very early prostate cancer. For 85 percent of men with prostate cancer, the cancer is caught early. The outlook for these patients is good.
If your doctor suspects that a patient might have a prostate abnormality, he or she may order additional tests. These might include:
- Ultrasound: Ultrasound testing uses a small probe, about the size of a finger, inserted in the rectum. The ultrasound wand uses sound waves to make a picture of the prostate gland for experts to examine.
- Biopsy: Through a thin needle, a physician collects a sample of tissue from the prostate gland. A laboratory analyzes the sample to determine whether cancer cells are growing in the prostate. A prostate biopsy is the only method of definitively diagnosing prostate cancer.
If these tests indicate cancer is present, the patient will be assigned a Gleason score. The Gleason score is a scale based on the results of the blood test and how biopsied tissue looks. It is a way for physicians to understand how aggressive the cancer might be and helps them in assessing the stage of the prostate cancer.
For cancers that are more advanced, doctors will order more tests to find out if the cancer has spread within the body. These tests might include:
- Computerized tomography (CT) scan
- Magnetic resonance imaging (MRI)
- Bone scan
- Positron emission tomography (PET) scan.
Not every patient needs to have all of these tests. Doctors will tell patients which tests are right for them.
Treatment of prostate cancer
Treatment options will be different for each patient, depending on the stage of the cancer, the age of the patient and other factors. The treatments for prostate cancer page provide more details about the variety of available treatments, some of which are listed below.
- Observing detected cancer but providing no treatment is often called “watchful waiting” or “active surveillance.” The major flaw in this approach is that men don’t return to see their doctor for updated surveillance.
- Hormone therapy to stop the body from producing testosterone, which cancer cells rely on for growth.
- Radiation therapy, either Cyberknife/SBRT, external beam or internal insertions of radioactive seeds that deliver radiation (brachytherapy).
- Surgery to remove the prostate. This can be done laparoscopic of robotically with small incisions or using the traditional open approach.