Last week’s publication of my book Let Sleeping Dogs Lie? What men should know before getting tested for prostate cancer (free download here) has provoked a stream of testimonials from men who had their prostate cancer found via a PSA test, had it treated (mostly by prostatectomy to surgically remove the prostate, or by various forms of radiotherapy), and now live to tell the tale. The tale is basically “Thanks to the test, we found the cancer early. Obviously I’m still alive. Ergo, the test and the early detection saved my life. Every man should be tested annually.”
Prostate cancer survivor Treasurer Wayne Swan is perhaps the most prominent Australian man who strongly advocates for the test, in 2003 telling the then head of Cancer Council Australia, the PSA test refusnik Professor Alan Coates, that his public position would “condemn many young men in this country to death”.
But just as interviewing lottery winners is not a sensible way of making informed judgements about the odds of winning, so is it unwise to use the “I’m alive” testimony of post-treatment survivors as a guide to the value of the test.
The simplest way of explaining the odds of having a PSA test save your life is to look at the results obtained from a long-running, Europe-wide, randomised controlled trial of PSA screening. It found that for every 1000 men aged 55-69 who were allocated to the screening arm of the trial and were then followed for 10 years, 93 had prostate cancer diagnosed and treated and three died from the disease over the following 10 years. In 1000 unscreened men allocated to the “control” arm of the trial, 55 (who would have mostly been tested following noticing symptoms) were found to have the disease and four died over the same period. So, PSA screening finds cancer, and yes it prevents deaths from prostate cancer, but to a soberingly small degree.
A more recent Swedish trial reported better outcomes, but commentators in the Lancet and from the US National Cancer Institute have suggested there are few lessons in the Swedish results for nations such as the US and Australia where de facto PSA screening has been occurring since the late 1980s.
Most of those who remain alive after treatment are convinced that they would be otherwise dead. Some would be, but the widespread occurrence of “indolent”, non-life threatening cancer shows that there is much over-treatment. In our book from page 34, we show complete Australian data on age standardised prostate cancer deaths and incidence rates (the rate of prostate cancer per 100,000 men). In the 39 years 1968-2007, the age standardised death rate from prostate cancer has varied very little, with an average of 35.8/100,000 men and a range of 32.2 to 43.7. The most recent rate in 2007 (31/100,000) was very similar to the death rate at the beginning of this 38 year series in 1968 (35.6/100,000). In between there was a rise in the death rate (in the early to mid 1990s), which has now reversed back to rates seen in the early 1970s, a decade before the PSA test became available.
However, when you look at the data on prostate cancer incidence, the same basically flat trend we see for deaths is not apparent. Instead there is a dramatic leap in the incidence of the disease from the early 1990s. This change has been largely sustained ever since, resulting in a startling difference in the risk of men being diagnosed with prostate cancer before the 1990s (approximately one in 22 men in their lifetime) to nearly three times that today (one in 8).
The massive rise in finding prostate cancer has not been matched by any remotely comparable fall in the rate of prostate cancer deaths. Lots of cancer is being found that would not have killed the men with it. And lots of that cancer is being unnecessarily tested. The big problem is that current diagnostic tools are poor at differentiating the nasty, fatal cancers from those that are indolent.
When you are diagnosed with prostate cancer, you are henceforth “on the bus” of treatment. Many will have radical surgery or radiotherapy and we know from statewide data in NSW that long-term impotency rates average 77% and incontinence rates 12% in treated men. Quality of life is dramatically altered in most men. To this, the president of the Urological Society Dr David Malouf says: “There is no evidence that we are over-diagnosing or over-treating prostate cancer.”
Many men who have survived prostate cancer have enduring s-xual and incontinence problems. Here’s what one (John) wrote to a discussion board this week: “I was screened 12 years ago and 32PSA … I had no symptoms … the discovery of my high PSA resulted in me losing my female partner. Decided to scale down house so sold my impressive four-bed for a two-bed flat. My turning down a high-profiled job offer managing a shopping mall. God only knows how much stress. Radiotherapy that virtually nuked my s-x life, etc etc. Here I am 12 years later, still no symptoms. New female partner decides to leave (now a pattern with prostate cancer). Total wipe out of s-x ability. Almost made incontinent, but thankfully now sorted. Intense stress levels. Employer now alerted to my vulnerability, etc, etc. so career prejudiced etc. So from my point of view whilst I value of course all the treatment and care I have received, I have never had any symptoms and wonder where I would be now if I had not taken this PCa medical course. I’d certainly be in a happy relationship, have a better job, look younger and be far less cynical.”
Less than 3% of prostate cancer deaths are in men aged less than 60 and more than half occur in men aged over 80, which exceeds average life expectancy today. No international expert group outside of urology has ever promoted mass testing.
*Professor Simon Chapman, School of Public Health, University of Sydney