What are the tests for Prostate Cancer?
The main test for Prostate Cancer is the determination of the levels of Prostate-specific antigen (PSA) in the blood (with a normal level being 4ng/ml of blood). See this page on PSA tests to learn more.
Other tests for prostate cancer include:
Digital Rectal Exam
This is a manual examination where the doctor inserts a gloved, lubricated, finger into the patient's rectum to feel for any irregular or firm area on the prostate. Something that might be indicative of cancer. The prostate gland is located just in front of the rectum, and most cancers begin in the back part of the gland that can be reached by a rectal exam. While it is uncomfortable, the exam causes no pain and only takes a short time.
Though it is a less sensitive technique than the determination of PSA levels this type of examination can sometimes be used to confirm the presence of cancer in men with otherwise normal PSA levels.
DRE examination can also be used on men diagnosed with prostate cancer to help determine whether the tumour has spread beyond the prostate gland itself (causing a secondary tumour). It is also used after treatment to determine whether or not the cancer has re-emerged.
Transrectal Ultrasound (TRUS)
Transrectal Ultrasound (TRUS) uses ultrasonic pulses to form an image of the prostate which is then displayed on a video monitor (this is the same basic technology used to create images of developing babies). In TRUS, however, a small probe is inserted into the rectum. This creates ultrasonic waves that enter the prostate and are echoed back to the probe which picks them up and sends the signal back to the computer. Software in the computer then translates these sound waves into a digital image of the prostate and the surrounding area.
Unfortunately TRUS is not a very sensitive technique and it does not often spot early cancer. Instead, it is most commonly used during a prostate biopsy to guide the biopsy needle into the correct area of the prostate.
The Prostate Biopsy
A technique called core needle biopsy is the main method utilized to diagnose prostate cancer. Here the doctor inserts several small needles through the rectum and into the prostate gland. As the needle is withdrawn it brings with it a plug of tissue about 1cm long and 1.2mm across which can be examined under a microscope to detect cancerous cells.
Usually between 6 and 15 separate samples are taken from different areas of the prostate to check whether cancer is present and to see how much of the prostate gland is affected.
Even this procedure is not entirely infallible. Because the samples taken are small and the prostate gland is large in comparison a biopsy may still miss the tumour. (Such a result is called a 'false negative'). If your doctor still strongly suggests that you have a tumour you may be called back for a repeat biopsy if this happens.
The procedure above may sound painful, but in reality it is not. The biopsy is generally taken with a biopsy gun which takes the sample in a fraction of a second. Usually the region in which the biopsy is to be taken will be numbed with a local anaesthetic. The biopsy procedure itself usually takes no more than fifteen minutes. Afterwards there may be some soreness in the biopsy area and blood in the urine may be seen for a few days afterwards but this is temporary and soon disappears.