How is prostate cancer diagnosed?
Your general practitioner (GP) conducts a blood test, often as part of a suite of blood tests, and/or a physical examination:
Blood test (Prostate Specific Antigen – PSA)
This blood test identifies whether there has been an increase in a protein in your blood, that may indicate you need further investigation by a specialist.
Digital Rectal Examination (DRE)
This allows your doctor to feel the size of the prostate and check if there are any abnormalities. Occasionally a cancer can be felt this way, but not always. A normal DRE exam does not rule out prostate cancer.
Even if positive, neither of these tests make the diagnosis. In fact, most men with a high PSA test result do not have prostate cancer. More tests are required.
If the above tests are positive, your doctor may request to repeat them and refer you to a urologist (a doctor who specialises in the urinary and reproductive area) who may suggest:
Free Total PSA ratio
If you have a moderately raised PSA score and your doctor is not sure whether you need a biopsy, you may have another test to measure the “free PSA” in your blood – that is, the PSA molecules that are not attached to other blood proteins. A decreased level of free PSA can indicate prostate cancer.
Prostate Health Index (PHI)
A combination of three blood tests that measure different forms of PSA protein. When reviewed together they may provide a risk assessment for prostate cancer.
A urine test which measures the level of the PCA3 gene and which, when looked at in conjunction with the PSA test, can help your doctor decide whether you need a biopsy.
The only way prostate cancer can be definitively diagnosed is with a prostate biopsy. Your specialist removes small samples of tissue from your prostate using a very thin, hollow needle, guided by an ultrasound or MRI. The prostate is either reached through the rectum (transrectal) or the perineum (transperineal), which is the area between the anus and scrotum. A biopsy is usually done as an out-patient procedure and your doctor will likely advise a course of antibiotics afterwards to reduce the chance of infection. The tissue is sent to a pathologist to identify whether the cells are malignant (i.e. cancerous) or benign (i.e. non-cancerous).
Source: Reproduced from pcfa.org.au with minor modifications and with the kind permission of the Prostate Cancer Foundation of Australia.
Magnetic Resonance Imaging (MRI) is a safe, painless and powerful diagnostic imaging test. MRI technology is very complex but essentially uses a strong magnetic field and radio waves to produce exquisite images of the prostate. MRI does not use radiation. Prostate MRI scans are typically completed within 40 minutes
What is the evidence for Prostate MRI?
The likelihood of having prostate cancer can be determined by digital rectal examination and a blood test which measures PSA, a protein secreted by normal prostate cells and in larger amounts by prostate cancer. The problem is that an elevated PSA does not definitely indicate prostate cancer as it can also be raised in non-cancerous conditions such as aging related enlargement, inflammation and infection. In fact, certain activities like having sex or riding a bike can trigger a temporary increase in PSA that has nothing to do with prostate cancer and conversely a normal PSA does not exclude prostate cancer.
Systematic biopsies of the prostate until recently have been the gold standard for evaluating raised PSA and prostate cancer diagnosis. Whilst they have been shown to save lives, biopsies have also been shown to detect relatively harmless, insignificant cancers which pose no real threat to a man’s life expectancy. Furthermore, a biopsy sometimes will miss an aggressive cancer particularly if it is located in the front part of the prostate gland beyond the reach of the biopsy needle.
Prostate Multi-Parametric MRI is a non-invasive imaging test that has emerged as the best examination available for detecting significant (‘harmful’) prostate cancer earlier. It is also advantageous that MRI does not pick up harmless cancers which would lead to unnecessary over treatment.
It also enables accurate evaluation of spread outside the prostate gland which is important when it comes to treatment options. Understanding the extent of disease enables the surgeon to determine whether it is possible to preserve the delicate arteries and nerves which are essential for maintaining sexual function and bladder control.
Pre Biopsy MRI
If your PSA is elevated, many world experts consider having an MRI prior to a biopsy to investigate prostate cancer worthwhile. In some patients, MRI can be so convincingly negative that specialised radiologists can conclude that there is no significant cancer in the prostate even more reliably than with biopsy .
This means your doctor may decide not to proceed to a biopsy. The MRI will, in essence, provide peace of mind. If you and your doctor still decide to proceed to a biopsy, your MRI will add considerably to the certainty that a significant cancer is not missed by the biopsy.
If cancer is detected on MRI, the MRI will give better information with regards to its location, size, grade and extent. This is important information for urologists to aid diagnosis and treatment planning.
Perth Radiological Clinic, and other radiology practices, offer prostate multi-parametric MRI scans. Perth Radiological Clinic offers this service in Joondalup, Midland Public Hospital, Murdoch and Subiaco. The mission of Perth Radiological Clinic is to provide doctors, and most importantly patients, with un-paralleled precision diagnostic imaging so that health-related decisions can be made with confidence.
Post Biopsy MRI
If you have already had a biopsy, which did not show cancer and your PSA is still raised or rising, a subsequent MRI can further evaluate for missed prostate cancer as a possible cause for your elevated PSA.
There is also evidence that MRI has added an extra dimension to the monitoring of men undergoing active surveillance or follow up after radical treatment, resulting in many fewer biopsies.
How long will the procedure take?
The time in the MRI room is approximately 40 minutes. After the examination normal activities can be resumed
The results of all tests give doctors an overall picture of the prostate cancer diagnosis. It is only then that the correct treatment options can be discussed.