Once prostate cancer is suspected the medical provider will perform several different tests and procedures to confirm or rule out the diagnosis.
The most common blood test performed to diagnose prostate cancer is the prostate-specific antigen (PSA). The PSA measures the amount of prostate-specific antigen present in the blood. Men without prostate cancer often have PSA levels under 4 nanograms per millimeter of blood. If a man’s PSA level is between 4 and 10, then there will be a 25% of chance of having prostate cancer and if the PSA level increases to more than 10 then the chance of having prostate cancer rises to 50%. Although this is a fairly accurate method of predicting whether a man has prostate cancer, it is not foolproof. Nearly 15% of men with PSA levels below 4 will have prostate cancer. Therefore, doctors must use the PSA blood test in conjunction with other tests to confirm a prostate cancer diagnosis.
A biopsy is performed on the suspected tumor to detect or rule out cancer. The doctor uses a special tool to take a small sample of the prostate, tumor, or surrounding areas like lymph nodes and examine it under a microscope. Often multiple biopsies from the same tissue will be taken to ensure that the cancer is not missed. The biopsy method is used to accurately stage and grade any identified cancerous tissue. There are drawbacks to biopsy, however, in rare cases, men have lost their ability to have an erection of the biopsy was not performed properly.
Transrectal ultrasound (TRUS): The TRUS procedure is performed by placing a small ultrasound probe in the rectum. This probe can detect the specific location of a tumor and can even detect tumors that were not felt during a rectal examination.
Bone Scan: A bone scan is performed to identify if the prostate cancer has spread to the bones. This test is performed through the injection of a small amount of radioactive liquid that travels to and identifies areas with damaged bone.
CT Scan: A CT scan is rarely performed for prostate cancer, but doctors can use it to identify if the cancer has spread to lymph nodes. This procedure is performed using X-rays which allow for the production of detailed body images.
MRI: Similar to CT scans, MRIs also take very detailed images of the body. However, instead of X-rays, MRIs use radio waves and magnets to produce the images. Doctors use MRIs to take detailed images of the prostate. Like CT scans, MRIs are rarely used for diagnosis and instead can be used to determine treatment options or identify certain characteristics of the tumor.