Screening and Diagnosis
There are two main screening tests used to detect prostate cancer: the digital rectal exam (DRE) and the prostate-specific antigen (PSA) blood test).
In DRE exams, your physician inserts a lubricated, gloved finger into the rectum to feel for abnormalities. PSA exams detect the substance produced by the prostate that may be found in an increased amount in the blood in individuals with prostate cancer, benign prostatic hyperplasia, or infection or inflammation of the prostate.
Note: The DRE and PSA exams can often detect problems with the prostate, but they cannot determine whether such a problem is due to cancer or a less serious condition. Your physician will often use the results of these tests to decide whether or not to perform a biopsy of the gland. Talk to your physician about these exams or prostate cancer if you have any questions.
Beyond taking your medical and family history, physical exam and laboratory exams into consideration when screening for prostate cancer, your doctor may also perform the following exams: transrectal ultrasound and biopsy.
During the transrectal ultrasound, your doctor will insert a probe that sends out sound waves into the rectum to check for abnormal areas. The sound waves bounce off the prostate and create a computerized photograph called a sonogram.
A biopsy is the only definitive way to diagnose prostate cancer.
If prostate cancer is detected, the pathologist will usually report the grade (severity) of the cancer cells using the Gleason score system. The cells are assigned a number between 1 and 5-nearly normal cells are Grade 1 and the most abnormal are Grade 5. Then the grades of the two most common cell patterns are added together to determine the Gleason sum. Gleason scores range from 2 to 10. The higher the score, the more aggressive the cancer.
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Biopsy: The removal of cells or tissues for examination under a microscope. When only a sample of tissue is removed, the procedure is called an incisional biopsy or core biopsy. When an entire lump or suspicious area is removed, the procedure is called an excisional biopsy. When a sample of tissue or fluid is removed with a needle, the procedure is called a needle biopsy or fine-needle aspiration.
Digital rectal exam (DRE): An examination in which a doctor inserts a lubricated, gloved finger into the rectum to feel for abnormalities.
Gleason score system: A system of grading prostate cancer cells based on how they look under a microscope. Gleason scores range from 2 to 10 and indicate how likely it is that a tumor will spread. A low Gleason score means the cancer cells are similar to normal prostate cells and are less likely to spread; a high Gleason score means the cancer cells are very different from normal and are more likely to spread.
Prostate-specific antigen (PSA): A substance produced by the prostate that may be found in an increased amount in the blood of men who have prostate cancer, benign prostatic hyperplasia, or infection or inflammation of the prostate.
Transrectal ultrasound: A procedure in which a probe that sends out high-energy sound waves is inserted into the rectum. The sound waves are bounced off internal tissues or organs and make echoes. The echoes form a picture of body tissue called a sonogram. TRUS is used to look for abnormalities in the rectum and nearby structures, including the prostate. Also called endorectal ultrasound.