John von Arnim looks at claims the common PSA test for prostate cancer is over-used.
Movember last year prompted a rash of highly publicised on-air prostate exams in the US. The doctor who inserted his digit into the rectum of Today Show host Matt Lauer famously claimed that he had to lose over two kilos to make his finger smaller for the job. But it didn’t take long for the irrepressible Stephen Colbert to parody the trend by inviting three potential celebrity examiners to compete for the honour of giving him a fake rectal exam on a segment dubbed “November Sweeps Prostacular”. Actor Jon Lithgow, indie rock band The Black Keys and news anchor Katie Couric took part in a latex glove ceremony with Lithgow emerging the winner.
Prostate cancer is rarely a topic for jokes. Apart from skin cancer, it is the most common cancer among Australian men with nearly 20,000 new cases detected each year. In 2013, close to 240,000 new cases were diagnosed in the US, more than any other cancer. Nearly 11,000 men die from prostate cancer in the UK each year and 40,000 new cases are detected.
Grim stats that disguise the fact that doctors do not have a 100 per cent accurate method of spotting prostate cancer. The blood test routinely used in all three countries measures levels of protein known as PSA (prostate specific antigen). Unfortunately, it isn’t always accurate and can lead to unnecessary rectal exams and biopsies.
Richard Ablin, the scientist who first identified the PSA antigen in 1970, has been fighting against the over-use of the PSA test for decades. In a recently published book, co-authored with Ronald Piana – The Great Prostate Hoax: How Big Medicine Hijacked the PSA Test and Caused a Public Health Disaster – he re-ignited an on-going debate which has divided medical opinion. Many doctors believe that PSA testing identifies prostate cancer earlier before it becomes serious or life-threatening. But many other physicians argue that PSA screening has lead to an increase in needless and expensive rectal exams and biopsies.
In 1986, the US Food and Drug Administration, the de facto world watchdog on regulatory issues, approved the PSA test to monitor men who had already been diagnosed with prostate cancer. Eight years later, the USFDA authorised the procedure to be used in the detection of the disease in men aged 50 or older. The PSA test became a common procedure in the US and Australia during the 1990s and routine screenings became the norm for older men and younger men with a family history of prostate cancer.
It’s what happened next that caused Ablin to become such a crusader. PSA screening itself is simple – just a blood test. But far too many doctors recommended invasive biopsies, he says. The medical profession is up in arms, of course, and many doctors have accused Ablin of being too emotional in his accusations and claim that many of his arguments aren’t backed by the facts.
Apart from his own extensive studies, however, Ablin does have a growing body of research on his side. While it’s true that deaths from prostate cancer plummeted by 45 per cent in the US from 1993 to 2010, the number of deaths began dropping before the widespread introduction of PSA screening. Critics of the PSA test say that it identifies prostate cancers that have little probability of becoming life-threatening, producing artificially high statistics.
Two major studies have strengthened the position of the nay-sayers. A US trial found that PSA screening produced a minimal increase in life-saving treatment, in contrast to a control group. A large scale European study concluded that PSA testing was of only moderate benefit to men aged 55 to 69 and estimated that the procedure was crucial to approximately one man in every 1,000 who underwent screening. In 2012, such findings prompted a US government panel to recommend that no man should routinely undergo a PSA test.
The recommendation caused uproar among doctors worldwide and last year the Prostate Cancer World Congress rubber-stamped its recommendation of PSA screening for men aged 50 to 69 with baseline testing for men in their 40s.
Big Pharma have been committing major R&D funds to discover a new test for prostate cancer with various degrees of success. A new test developed by researchers at Surrey University in the UK promises to be the biggest breakthrough in prostate cancer detection in 25 years. Based on a urine test – no needles – it scans urine for a protein called EN2 which is only produced by people with tumours. In trials, the new test detected about 70 per cent of prostate cancers – double the accuracy rate of PSA testing.
With a price tag as low as $20, the EN2 test means that invasive rectal exams could become a thing of the past. The inventors, Professor Hardev Pandha and Dr Richard Morgan, have already negotiated deals with two leading medical companies and the test could be available in the UK within a year.