The prostate is a relatively small gland (about the size of a walnut) that sits at the base of the penis. The prostate is responsible for the synthesis and excretion of the fluid portion of semen. Several diseases can afflict the prostate, ranging from infection (particularly from bacteria) to cancer.
Digital Rectal Exam
According to the American Cancer Society, one test that can be performed on the prostate is the digital rectal exam. With this test, a physician inserts a gloved and lubricated finger into the patient's rectum and then palpates the prostate through the wall of the colon. This kind of exam can be used as a screening test for prostate cancer because the physician may be able to feel any irregularities in the prostate's surface that can be a result of prostate cancer. This test can also identify enlargement of the prostate. However, in March 2010, the American Cancer Society issued new guidelines in which it advocated cutbacks in the use of digital rectal exams to find tumors because of lack of evidence that they save lives.
Prostate Specific Antigen
Another test that can be used to assess the health of the prostate is called the prostate specific antigen (PSA) test. Prostate specific antigen is a molecule that's released into the blood by the prostate. Elevated PSA levels can be caused by prostate cancer, so this test is often used as a screening test. Elevated PSA levels can be caused by other conditions, however, such as prostatic inflammation (prostatitis), old age, and a non-cancerous enlarging of the prostate (also known as benign prostatic hyperplasia). Guidelines announced in 2010 said that doctors should better educate men about the risks and benefits of using the PSA test for screening.
Urinalysis
Urinalysis, according to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), is a way of testing to see if the prostate has become infected with bacteria. This kind of test typically involves the patient urinating on a dipstick that has been treated with special chemicals. The dipstick changes color if the urine contains nitrates, which are often a byproduct of bacterial infection. Sometimes the patient needs to urinate before and after a massage of the prostate to see if the amount of bacteria increases (increased bacteria after the massage suggests that the infection is in the prostate and not elsewhere in the urinary tract).
Imaging
Computer-assisted topography (CT) and magnetic resonance imaging (MRI) scans can also be used to visualize the prostate. These techniques can be used to visualize the prostate in three dimensions, or to make cross-sectional images. MRIs and CT scans can help identify abnormalities that could be prostate cancer.
Biopsy
With a prostate biopsy, a small needle is inserted into the prostate (typically into a potentially cancerous mass) to obtain a small amount of tissue. This tissue can later be analyzed under a microscope to determine whether the sampled cells are cancerous. Prostate biopsy is typically the most definitive way to diagnose prostate cancer.
