Recently, The UK National Screening Committee has been calling for further research into alternative screening tests for prostate cancer.
We spoke with the highly regarded consultant urologist, Mr Mathias Winkler, about the efficiency of diagnosing and treating prostate cancer. We discussed the possibility of having a 'prostagram' in future (like a mammogram) as well as the results of one of his recent clinical trials regarding the effectiveness of PSA tests.
What is a PSA test and how does it work?
The PSA test is a blood test used primarily to screen for prostate cancer. The test measures the amount of prostate-specific antigen (PSA) in the blood. PSA is a protein that is usually produced by both cancerous and noncancerous tissue in the prostate, the small gland that sits below the bladder in men.
However, The UK National Screening Committee have decided against prostate cancer screening using PSA testing on the basis that it " is still a poor test for prostate cancer and a more specific and sensitive test is needed”.
Are there any alternative ways of diagnosing prostate cancer?
There has been a surge of interest into a range of alternatives to PSA for prostate cancer screening. MRI as a diagnostic test in secondary care has worked very well and so the question has arisen as to whether MRI could be adapted for widespread use in the general population as a screening test.
Although there are legitimate concerns over its high cost and limited availability, recent technological advances have meant that a quick MRI could be a feasible screening test. Several clinical trials have also commenced assessing such an abbreviated bi-parametric MRI for screening men.
How effective are MRI scans at detecting prostate cancer?
Journalists have written evocative headlines regarding quick MRI scans. such as “10-minute scan may become the universal screening tool for prostate cancer”. These headlines have been met with a degree of scepticism by urologists especially as we are currently in the early stages of accepting MRI in hospitals as a triage before biopsy.
What are the symptoms of prostate cancer and what is the survival rate?
It's asymptomatic until it's at a more advanced stage. The disease is often slow-growing and the 10-year survival rate is high even for intermediate and high-risk disease.
This slow progression of prostate cancer is an advantage for screening as it should provide a greater window of opportunity for detection, and therefore curative treatment, provided there is a test which can accurately identify the disease. Most international guidelines have adopted the decision to use PSA testing in the community.
Can men in the UK choose to have a PSA test?
Yes, they can. However, the benefits and risks of PSA should be fully explained to them, particularly as it is unclear whether the benefits from PSA screening outweigh the negative impact it could have.
Patients sometimes end up deciding to have a biopsy (even if in actual fact, their prostate cancer is slow-growing, so it is unlikely to affect them) which can cause side effects, such as pain, infection and blood in the semen and urine.
So how effective are PSA tests really?
Outcomes of trials regarding PSA tests have been mixed with the three largest trials producing conflicting results. Two of them did not find any mortality benefit from PSA screening. Robust evidence of this comes from The European Randomised Study of Screening for Prostate Cancer that was carried out by David-Eldred Evans, Hashim U Ahmed (ERSPC), and myself.
We evaluated the outcomes of PSA screening across eight European countries. The 16-year outcomes found that PSA can lead to a small improvement in prostate cancer mortality. However, this was not constant across all countries.
Although PSA screening may reduce prostate cancer mortality, the disadvantage is the high rate of overdiagnosis. The overdiagnosis rate of insignificant cancer is high when using a screening strategy where PSA is combined with transrectal ultrasound guided (TRUS) biopsy.
The detection of this low-risk disease can lead to men being subjected to the harmful effects of a cancer diagnosis and the risk of side-effects from very radical treatment. However, underdiagnosis could mean there is a risk of missing significant prostate cancer.
What is the likelihood of having a more accurate and effective diagnostic test similar to a mammogram?
The idea of a male equivalent of the breast mammogram has been a long-standing goal in prostate cancer diagnostics. Image-based screening has been adopted for other common cancers, including mammography for lung cancer and breast cancer screening.
At present there have been limited studies evaluating MRI as a replacement for PSA and so more conclusive evidence is needed. However, small early studies show that MRI might have a higher diagnostic accuracy compared to PSA.
For effective screening of prostate cancer, we recommend getting in contact with leading consultant urologist, Mr Mathias Winkler. Click here to visit his Top Doctors profile today for information on appointment availability.