Prostate cancer: what is the PSA test and when do I need it?
Written by:Prostate cancer is a type of cancer that occurs in the prostate of men and is one of the most common types of cancer affecting men over 65. Like most cancers, if it is detected early, it can be easily managed and treated. Mr Simon Brewster, a consultant urological surgeon based in Oxford, is here to tell us the importance of having a PSA test and what you can expect if the result shows the presence of prostate cancer.
What is the PSA test?
The PSA test is a commonly performed blood test that measures the amount of prostate-specific antigen (PSA) there is in the blood. Prostate-specific antigen is a protein made purely by the prostate gland for reproductive purposes and leaks into the bloodstream by accident. It gets into the bloodstream in higher quantities when the vascular supply of the prostate gland is abnormal such as when it is infected or inflamed or in prostate cancer. However, it can also leak into the bloodstream in higher quantities when the prostate is simply enlarged in a benign fashion. This is common as men get older, but also goes up slightly when there has been recent sexual activity or strenuous cycling.
It's important to do the PSA test when middle-aged or elderly men come to the doctor complaining of symptoms of urinary bladder voiding, or if prostate cancer is suspected. There isn't a screening programme for prostate cancer, so PSA won't be done automatically by most doctors. It's very important to rule out a urinary infection before the PSA test is taken.
Is it reliable enough to find all prostate cancers?
No, the PSA test is not entirely reliable. In fact, about 10% of cancers can be found in men with a normal PSA test and up to three-quarters of men who have an abnormal test do not have cancer.
If the PSA level suggests prostate cancer, what happens next?
When a patient comes to see me who has an abnormal PSA according to his age, I want to perform an examination called a digital rectal examination which enables me to feel the back surface of the prostate just inside the rectum. It is slightly uncomfortable and usually takes about 30 seconds. I am looking to see if the prostate gland feels enlarged or tender which would suggest inflammation, or whether it might contain hard areas or nodules. After that, and assuming there is no urinary infection, I would probably recommend a dedicated prostate MRI scan and then consider a prostate biopsy once the scan has been done.
What happens during a prostate biopsy? What do the results mean?
A prostate biopsy is a procedure where we take small snippets of prostate tissue to send to a pathologist in the laboratory to look at down a microscope to decide whether or not cancer is present. The procedure is usually done under local anaesthetic and takes around five minutes. This procedure can feel slightly uncomfortable. The result of the biopsy usually takes one to two weeks to come back and it tells us whether or not there is cancer present and how much. It also informs us of the aggressiveness of the disease.
When are imaging tests such as MRIs necessary to detect prostate cancer?
A prostate MRI scan is extremely useful in pinpointing regions of interest within the prostate and outside the prostate that may be relevant. If we see something in the prostate that looks suspicious, it can be targeted with a biopsy. Not all suspicious areas turn out to be cancer and in about one in six cases, there can be significant cancer found even when the MRI appears to be normal. So, some patients choose to have an MRI scan followed by a biopsy regardless of whether the MRI pinpoints an abnormality or not, whereas others will take the chance and avoid a biopsy if the MRI looks normal.
What can I expect next following positive test results after all these measures?
Following a diagnosis of prostate cancer by biopsy, it's important to decide whether or not treatment is necessary. And I say this because some very small, non-aggressive prostate cancers grow extremely slowly and there is no threat from them during the following 10 or 20 years. So we manage these with what we call active surveillance which involves PSA testing and occasional repeat MRIs and biopsies. The benefit of this is that it avoids the side effects of treatment for a lot of men. However, if the disease is slightly higher grade or aggressive, then curative treatment is necessary.
Treatment usually involves surgical removal of the prostate which is called a radical prostatectomy or radiotherapy delivered with either external beam or implant of brachytherapy seeds. However, if it has spread away from the prostate and has gone to bones, lymphatic glands, liver or lungs (which is uncommon) we can't treat it with surgery or radiotherapy. In this case, we have to offer drug treatments with chemotherapy and hormonal therapy to suppress it.
Mr Simon Brewster is a consultant urological surgeon based in Oxford. To book an appointment with him, visit his Top Doctors profile and check his availability.
