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THE American College of Physicians released a “guidance statement” earlier this year recommending against prostate cancer screening. Considered in isolation, the reasons seem compelling.
In the US in 2012, more than 241 000 men were diagnosed with prostate cancer and 28 000 died of it. Prostate cancer is the second leading cause of cancer-related deaths in US men; one in six men (16.7%) will receive a diagnosis of prostate cancer in their lifetime, and 10- and 15-year relative survival rates are 98% and 91%, respectively, although the 5-year survival rate for invasive prostate cancer can be as low as 28%.
In Australia in 2012, prostate cancer was the most commonly diagnosed cancer in men, with a one in eight risk of being diagnosed with it before the age of 75 years. In 2010, 3235 men died from prostate cancer.
The proportion of men who are diagnosed with prostate cancer but never have associated clinical symptoms is difficult to estimate, but it may range from a low of 23% to a high of 66%.
A false-positive rate of 10%–12% for screening prostate-specific antigen (PSA) levels greater than 4.0 ng/mL (and even higher in some studies) and the harms associated with treating men with cancer that would not have become clinically evident in their lifetime have apparently influenced the guidelines to recommend against screening.
But how does this compare with breast cancer statistics and the response to them?
In the US in 2012, about 227 000 new cases of breast cancer were diagnosed in women, with about 40 000 deaths. Breast cancer is the second leading cause of death in women. One in eight US women (12.4%) will receive a diagnosis of invasive breast cancer in their lifetime and 10- and 15-year relative survival rates are 82% and 77%, respectively.
In Australia, breast cancer is the most commonly diagnosed cancer in women, with a one in 11 chance of being diagnosed before age 75 years. In 2010, 2840 women died from breast cancer.
The false-positive rate of 8%–21% for screening mammography and the estimated 10 breast cancers diagnosed and unnecessarily treated per life saved do not seem to have caused the same circumspection as with prostate cancer screening — even though the Cochrane Collaboration concluded it is not clear whether mammography screening does more harm than good.
I have written previously on the conflicting evidence of prostate cancer mortality reduction from screening derived from several studies.
Last year, the PIVOT Study, which assessed treatment by randomly assigning men with local prostate cancer to either radical prostatectomy or observation, found a 13.2% reduction in all-cause mortality among men with a PSA value greater than 10 ng/mL who had a radical prostatectomy. Perhaps if screening was more widely available more men found to have prostate cancer would be able to consider this option.
There is little evidence-based medicine to distinguish efficacy and harms between breast and prostate cancer screening. Yet none of this appears to have influenced some breast cancer screening advocates’ negative attitudes towards screening for prostate cancer.
When there is little to distinguish breast cancer from prostate cancer screening other than gender, men are entitled to ask why there is a difference in attitude and — more importantly — a difference in funding for the two cancers.
Dr Michael Gliksman is an occupational physician based in Sydney and chairman of the Professional Issues Committee of the AMA NSW. On Twitter @MGliksmanMDPhD
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“Contrarian” asks “”Why is the disparity between the life expectancy of men and women not an overwhelming national concern and worthy of diversion of large sums of money to investigate the causes and remedy the situation?” Easy – it IS.Hence the research and expenditure on road safety, coronary disease, smoking cessation, alcohol control, childhood accident prevention, regulation of high-impact sports….
To ‘Rose’; yes I have, in order to establish a baseline. Monitored every couple of years since. It’s something all men should consider when they turn 50.
Thanks for a great discussion guys, very interesting and up to date.
My question. Is it better to be fully funded for tests that lead to over-investigation and treatment, or under funded? I think under those circumstances, I’d rather be under-funded and safe from a high risk of unnecessary and disabling treatment. However, where studies are in conflict (1:3 vs 1:10 treatment to benefit ratios), perhaps the decision ought to be left up to the patient, following a clear explanation from their treating doctor.
My suggestion. It may not always be worthwhile extending our lives when the quality of that extension is in question. Bodies are a bit like cars – once they begin to age, one thing after another seems to go wrong, with the related increase in maintainance costs and decrease in performance. Lets be careful about how hard we try to extend life, regardless of the impact on its quality and regardless of the cost. Something always gets us in the end!
Perhaps the reason for the disparity in screening for these two diseases is part of larger question. Why is the disparity between the life expectancy of men and women not an overwhelming national concern and worthy of diversion of large sums of money to investigate the causes and remedy the situation?
Have you had a PSA done?
As we said, the ERSPC estimates the ratio of overdiagnosed cases to deaths averted at 48:1. We have many estimates for the ratio of overdiagnosed cases to deaths averted for breast cancer; they range from 1:1 to 10:1. The estimate of 3:1 was made late last year by the UK Independent Panel on Breast Cancer Screening.
Have mortality studies lost sight of the patient?
Absolute reductions in bone metastases is a good enough reason to screen and treat .
Actually Alex, Martin & Simon, the PIVOT Study authors went on to point out that:
‘Reductions in prostate-cancer mortality in the radical-prostatectomy group were limited to men with a PSA value that was greater than 10 ng per milliliter and to those with high-risk disease, with absolute reductions of 7.2 to 8.4 percentage points. Absolute reductions in bone metastases of 10.4 and 8.6 percentage points occurred, respectively, in men with a PSA value of 10 ng per milliliter or higher and in those with high-risk disease.”
The Cochrane Collaboration has this to say about breast cancer screening:
‘If we assume that screening reduces breast cancer mortality by 15% after 13 years of follow-up and that overdiagnosis and overtreatment is at 30%, it means that for every 2000 women invited for screening throughout 10 years, one will avoid dying of breast cancer and 10 healthy women, who would not have been diagnosed if there had not been screening, will be treated unnecessarily. Furthermore, more than 200 women will experience important psychological distress including anxiety and uncertainty for years because of false positive findings.’
And this about prostate cancer screening:
‘Among men aged 55 to 69 years in the ERSPC study, the study authors reported that 1055 men would need to be screened to prevent one additional death from prostate cancer during a median follow-up duration of 11 years. Harms included overdiagnosis and harms associated with overtreatment, including false-positive results for the PSA test, infection, bleeding, and pain associated with subsequent biopsy.’
Speaks for itself, really. If it’s not misandry, what is it?
It’s not about gender bias, it’s about differences in the balance between benefits and harms. For breast cancer screening there are 8 large randomised trials, and a Cochrane meta-analysis of them shows a significant reduction in breast cancer deaths. For PSA screening there are 5 randomised trials, and a Cochrane meta-analysis of them shows no reduction in prostate cancer deaths (only 1 of the 5 trials showed a reduction in prostate cancer deaths). Both prostate and breast cancer screening do harm through overdiagnosis. The estimated ratio of overdiagnosed breast cancers cases to averted breast cancer deaths is about 3:1. The estimated ratio of overdiagnosed prostate cancer cases to averted prostate cancer deaths is about 48:1. And while we’re at it, the authors of the PIVOT trial cited by Dr Gliksman concluded in their NEJM abstract that: “Among men with localized prostate cancer detected during the early era of PSA testing, radical prostatectomy did not significantly reduce all-cause or prostate-cancer mortality, as compared with observation, through at least 12 years of follow-up. Absolute differences were less than 3 percentage points.” So unless you want to see men being harmed by PSA screening at over 10 times the rate that women are harmed by breast cancer screening, in pursuit of a benefit which does not exist for most men with screen-detected prostate cancer, we suggest rigorous research to improve screening methods, not ill-informed lobbying to apply ineffective screening methods.
For mammography the screening genie is well and truly out of the bottle! Published guidelines endorse routine mammography. There are differences of opinion on when to start, how often to screen and when to stop, but it is now well established conventional medical “wisdom”. It seems unlikely it will become individualised rather than generalised, even though there are some doubts whether it does more harm than good.
For prostate cancer the screening genie is only halfway out of the bottle. On the currently available data screening for prostate cancer should be individualised. Factors such as age, family history and personality/expectations/wishes etc need to be factored in. The following document is helpful when having the discussion with patients about the pro’s and con’s of screening.
http://www.cancer.gov/cancertopics/factsheet/detection/PSA
Although screening for prostate cancer probably can reduce mortality from prostate cancer, the absolute risk reduction appears to be small.
PSA screening and the subsequent tests and treatments adversely affect many more men than they ultimately benefit.
It is reasonable that individualised rather than generalised screening should continue to be advocated until we are better able to detect the patients with prostate cancer who will benefit from intervention.
The question is not whether men should have the same access and funding for screening – it’s whether women should also be discouraged from screening when the evidence shows no benefit.
Major reviews of screening mammography shows that it does NOT contribute to reduced deaths from breast cancer. There is up to 40% overdiagnosis and in turn significant morbidity from needless interventions. It says more about politics than medicine that it remains “saintly”. Women are badly served by this. Men are being better served by the push against prostate screening.