A number of tests and investigations may be used to diagnose and then assess prostate cancer. Accurate assessment is important because the characteristics, size and grade of the cancer will determine the types of treatment that can be offered.
Clinical Assessment
Prostate specific antigen (PSA)
Prostate specific antigen (PSA) is a natural chemical produced by the prostate gland. Any condition that irritates or damages the prostate gland can lead to a leakage of PSA into the blood. PSA is a way of identifying abnormalities of the prostate, but it is not specific to prostate cancer alone.
Digital rectal examination (DRE)
Abnormalities in the prostate gland can be felt via a DRE. If a significant cancer is present in the prostate gland it may feel hard and knobbly, whereas the prostate is usually smooth. Sometimes the prostate may feel normal, even when cancer cells are present.
Trans-rectal ultrasound scan (TRUS) guided biopsy
This type of scan is used to measure the size of the prostate gland and to guide the biopsy needles.
CT scan (computerised tomography)
A CT scan takes a series of x-rays of an area of the body. These are fed into a computer which creates detailed pictures of the inside of the body. A CT scan may show whether the cancer has spread into the tissues around the prostate gland or into the lymph nodes near to the prostate.
MRI scan (magnetic resonance imaging)
This test is similar to a CT scan but uses magnetism instead of x-rays to build up cross-sectional pictures of the body.
Isotope bone scan
An isotope bone scan can pick up abnormalities of the bone that might be suggestive of secondary disease. About 40% of men with a PSA greater than 40ng/ml will have a positive bone scan.
The Gleason system
The Gleason system (named after the pathologist who invented it) is a widely used method for classifying, or grading, prostate cancer tissue.4