Shared decision-making policies for prostate-specific antigen testing do more harm than good, an international group of experts led by epidemiologist Dr Andrew Vickers argued in the BMJ last month.
Analysing data from 11 high income countries including Australia, the authors warn that ‘informed choice approaches’ for asymptomatic men have led to unnecessarily high testing rates and subsequent harm from overdiagnosis and overtreatment.
In Australia, 20% of men undergo PSA-testing annually, with about half getting a PSA test in their life-time—and testing rates are similar between the 45-74 and 75-84 age groups—despite the latter group being less likely to benefit, they write, citing this research published in 2022.
“Countries that have adopted screening policies based on shared decision making have seen high rates of PSA testing, particularly among men 70 years or older, who are particularly prone to overdiagnosis but do not benefit from screening,” the authors of the BMJ editorial write.
Dr Vickers and his colleagues suggest two potential solutions. One is to create a risk-based prostate cancer detection program that not only sets out evidence-based parameters for PSA testing, including restricting it to men aged 50-70, but also specifies optimal care pathways for diagnostic follow up and treatment.
Alternatively, they suggest a clear recommendation against PSA-testing, except in cases where a patient presents to a specialist with urological symptoms or a specific risk factor such as a BRCA gene mutation.
Both the Urological Society of Australia and New Zealand (USANZ) and the Prostate Cancer Foundation Australia (PCFA) agree that the current guidelines for PSA testing need to change—just not in the way the BMJ authors are recommending. If their suggestions are implemented, it’s likely to result in more men getting PSA-tests, rather than less.
Some quick background.
Currently, the PCFA guidelines recommend an informed choice approach for men aged 50-69 (and those with increased risk at younger ages)—but say men aged 70 or older should be advised that the harms may be greater than the benefits of testing in men of their age. Meanwhile, the RACGP Red Book guidelines recommend against screening asymptomatic men with PSA testing “because the benefits have not clearly been shown to outweigh the harms.”
But USANZ and the PCFA say that substantial advances in diagnosis and treatment pathways have reduced the harms associated with testing—and that the existing NHMRC guidelines, written in 2015 and published in January 2016, are now “out of step with current evidence and practice.”
Both the Red Book and NHMRC guidelines are under review, but it’s a slow process. The PCFA was commissioned by the federal government late last year to review the NHMRC guidelines, with the results expected in late 2024.
What are the advances that USANZ and the PCFA say have changed the risk benefit equation of PSA tests?
- They say multi-parametric prostate MRIs have reduced unnecessary prostate biopsies and detection of clinically insignificant prostate cancers.
- They identify advances in biopsy techniques (including trans perineal biopsies and MRI fusion), which have increased clinically significant prostate cancer detection and reduced the morbidity associated with biopsy.
- They add that 80% of Australian men with low-risk prostate cancers now undergo active surveillance, which reduces overtreatment.
- They say the Prostate Cancer Outcomes Registry has also dramatically improved quality control and standardised treatment
Urological surgeon and past president of USANZ, Associate Professor Prem Rashid, says opportunistic testing is particularly important since most men don’t go to the GP unless something is wrong.
He’ll often hear from men with a high PSA on their first test who wonder if it’s just suddenly turned up.
“And I’m thinking, ‘unlikely,’ as the PSA would be slowly rising in most men, so if they had been tested a year before, or two years before, we would have seen this much earlier,” Associate Professor Rashid says.
Associate Professor Rashid believes that decisions on PSA testing should be based more on individual risks, so for example he says that a 70-year-old who is fit and healthy with a life expectancy of more than 10 years would be a good candidate for a discussion and a PSA test, whereas someone the same age with ongoing serious medical issues may not be.
“We as clinicians deal with people on an individual basis, so we have got to let them know what their individual risk is,” he says.
He says that historically, prostate biopsies were done as a trans rectal biopsy, where the needle was put alongside an ultrasound probe in the rectum, leading to “higher than we would have liked infection rates.”
“These days we more commonly do a trans perineal biopsy where the biopsy needle is passed through the skin under the scrotum— so an area we can clean in preparation. As a result, infection rates are ultra-low,” Associate Professor Rashid says.
He also points to the Prostate Cancer Outcomes Registry (PCOR), which has shown that a significant number of men have low grade (grade group 1) prostate cancer, and that these men are being followed up appropriately, with active surveillance.
“The PCOR data shows that there are high numbers of men undergoing surveillance both in Australia and New Zealand, which means the message has filtered through and that surveillance is happening. The data shows that people are not being overtreated,” Associate Professor Rashid says.
“There is less chance of overdiagnosis because it is based on two PSAs with information from an MRI to help decide if a biopsy is warranted,” he continues.
Associate Professor Rashid argues that Australia is leading the way in prostate screening and treatment pathways, and that international data based on very different systems in different countries does not reflect the progress that has been made here.
“We have also been ahead of the curve on MRI & PSMA PET imaging (including Medicare funding). Patient access to treatment is also very good in general, even regionally,” he says. “All this makes direct cross country comparisons difficult.”
While we await the new guidelines, USANZ has released an interim position statement on PSA testing.
It recommends offering PSA testing to men over 50 who are “well informed” and have a life expectancy of at least 10 years—and from age 45 for indigenous men and those of African descent, as well as for men with a family history of prostate cancer. For men with BRCA2 mutations, it recommends offering PSA tests after age 40.
If the initial PSA test is greater than 3 ng/ml, factors such as age, family history, digital rectal examination and PSA density can help decide next steps, including the need for MRI and biopsy.
“All this helps address previous criticism,” Associate Professor Rashid says.
However, it’s safe to say that the debate is not yet settled, and shared decision making is unlikely to go away any time soon.
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