10 September 2018
September has been designated ‘International Prostate Cancer Awareness Month’ by various NGOs including the Prostate Cancer Foundation of Australia (PCFA).
As I’ve discussed in previous articles (see Diabetes: ‘awareness’ vs action, Preventing bowel cancer, Keep your brain young with greens and Cancer prevention: myths, cons and big fat lies), I am deeply mistrustful of ‘awareness’ days, weeks and months.
All too often, they create a climate of helplessness around feared diseases, promote ineffective or unproven screening tests, and either underplay or outright ignore effective prevention methods that people can employ to dramatically reduce their risk not just of the disease that the ‘awareness’ campaign is focused on, but virtually all chronic degenerative diseases that plague Westernised populations. Even worse, they promote fundraising activities centred on consumption of foods that increase the risk of the target disease!
Unfortunately, the ‘awareness’ campaign promoted by the PCFA is no exception to this general rule.
The major thrust of PCFA’s campaign can be summed up in the hashtag #GetChecked. They provide tweets for men to use in their social media networks, urging them to make an appointment with their GP to ‘get checked’:
You’ll note that the PCFA doesn’t elaborate on how men should be ‘checked’ for prostate cancer. In fact, a careful re-reading of the advice given by the PCFA reveals wordsmithing worthy of the finest spin doctor. The ‘long version’ advises men “to have a health check and talk to their doctor about prostate cancer”, cleverly dodging a direct endorsing of actual prostate cancer screening. However, the ‘tweet version’ juxtaposes the idea of booking a GP appointment with the hashtag #GetChecked, implying – without overtly stating – that men should book in to ‘get checked’ for prostate cancer by their GP.
Why not just advise men outright to ‘get checked’ for prostate cancer, without all the word games? Because as the PCFA knows only too well, routine screening for prostate cancer is not advised by top cancer authorities – including the Cancer Council – due to a lack of evidence of substantial benefit, and evidence of substantial harm.
Cancer screening is the practice of using diagnostic tests on people who have no signs or symptoms of the cancer they’re being screened for, in an attempt to detect the cancer at an earlier, and hopefully more treatable stage.
There are two screening tests that have been proposed for prostate cancer: PSA testing and digital rectal examination (DRE).
The PSA test measures the amount of prostate specific antigen, an enzyme produced solely by the prostate gland – hence its name, ‘prostate specific antigen’ – in the bloodstream.
Both healthy prostate cells and cancerous prostate cells produce PSA, and in the majority of cases, elevated PSA is not due to prostate cancer, but to other conditions such as benign prostatic hyperplasia (non-cancerous enlargement of the prostate due to aging), inflammation of the prostate (prostatitis).
In addition, ejaculation and bicycle riding can temporarily raise PSA levels. But how many men have been warned by their doctors to avoid cycling, sex and masturbation for at least 48 hours before their PSA test?
I wrote about PSA screening in a previous article, published several years ago. Since then, the US Preventative Services Task Force has issued updated guidelines on screening for prostate cancer with PSA. After an exhaustive review of the published literature, they concluded the following:
- 1000 men aged 55 to 69 years must undergo periodic PSA screening for 13 years to prevent approximately 1.3 of them from dying of prostate cancer.
- If the same 1000 men are screened for the same duration, 3 cases of metastatic prostate cancer will also be prevented by catchingthe disease at an early stage.
- Men participating in PSA screening will not actually live any longer, even if the test detects their prostate cancer at an early stage and it is successfully treated.
- There is inadequate evidence to assess whether 55-69 year old men with a family history of prostate cancer may experience any different level of benefit than the average-risk population.
- Men aged 70 years and older do not have a lower risk of dying of prostate cancer if they undergo PSA screening.
- Over the course of 10 years of participating in PSA screening, over 15% of men will have at least 1 false-positive test result (i.e. a rise in PSA, which raises the suspicion that they have prostate cancer). The diagnostic procedure used to investigate the cause of the raised PSA – biopsy of the prostate – include pain, blood in the semen, and infection. Approximately 1% of men who undergo prostate biopsies will suffer complications that require hospitalisation. The false-positive and complication rates from biopsy are higher in older men.
- 20% to 50% of men diagnosed with prostate cancer through PSA screening may be overdiagnosed – that is, diagnosed with a prostate cancer that would never have become symptomatic during their lifetime; they would have died with their prostate cancer rather than from it. Overdiagnosis rates rise with age and are highest in men aged 70 or older, because they are more likely to die of other causes before their prostate cancer becomes advanced enough to kill them.
- Overdiagnosis results in overtreatment – that is, treating prostate cancer in men who wouldn’t have died from it anyway. Overtreatment provides such men with no benefit, and substantial harms, including erectile dysfunction (2 in 3 men who undergo surgical removal of their cancerous prostate gland [radical prostatectomy], and over half of men who receive radiation therapy, suffer long-term erectile dysfunction); urinary incontinence (roughly 1 in 5 men who undergo radical prostatectomy need to use incontinence pads), and troublesome bowel symptoms (up to 1 in 6 men who have radiation therapy experience long-term bowel symptoms including bowel urgency and faecal incontinence).
- Men aged 70 or older have a greater risk of harms from diagnostic biopsy, and harms from treatment.
The scientist who discovered PSA back in 1970, Dr Richard Ablin, has argued vociferously against using PSA testing for prostate cancer screening for decades. He describes the promotion of PSA testing as “a public health disaster” because of the enormous sums of money wasted on it, and the almost incalcuable harm done to men (and their families) through overdiagnosis and overtreatment. Dr Ablin decries “the continual proselytizing of fear” of a disease with a lifetime risk of death of only 2.5%, describing PSA testing as a “cash cow” for urologists and other medical professionals who profit from patient’s progression “from PSA, to ultrasonography, to biopsy”, and then to radical prostatectomy and/or radiation therapy. You can watch an interview with Dr Ablin here.
The USPSTF also recommends against DRE as a prostate cancer screening tool due to a lack of evidence of benefits.
In the face of a spectacular lack of effective screening tools for prostate cancer, one wonders what the PCFA expects men will ‘get checked’ for when they make the suggested appointment with their GP.
In my fantasy world, the GP would seize the opportunity to review the man’s diet and lifestyle, and advise him of the evidence linking various factors to a heightened risk of prostate cancer:
- Dairy products: The Physicians’ Health Study, involving 21,660 male US physicians, found that men who consumed more than 2.5 servings of dairy products had a 12% higher risk of developing prostate cancer than those who had less than half a serving per day; higher intake of skim and low-fat milk intake increased the risk of low-grade, early stage, and screen-detected cancers; and men who consumed 1 serving per day of whole milk had a 49% higher risk of fatal prostate cancer than men who rarely consumed it. Even worse, men who regularly drank whole milk were 2.17 times more likely to die of prostate cancer than those who rarely or never drank it.
- Red and processed meat: A pooled analysis of 15 prospective cohort studies found an increased risk of advanced and fatal prostate cancers in men who ate more red meat – both fresh and unprocessed.
- Eggs: The same pooled analysis identified Participants a 14% higher risk of advanced and fatal prostate cancers in men who ate over 25 g of eggs per day compared to those who ate less than 5 g per day.
- Oily fish: The Danish ‘Diet, Cancer and Health’ study, which tracked over 27 000 men for up to 20 years, found that the risk of dying of prostate cancer rose 27% for each additional 25 g of fatty fish (e.g. salmon, tuna, sardines, mackerel, herring, kippers, eel, trout, mullet, trevally and snapper) eaten per day.
On the other hand, the following factors have been linked to a decreased risk of prostate cancer:
- Cruciferous vegetables: A 2012 meta-analysis found that intake of cruciferous vegetables such as broccoli, cabbage, kale and Brussels sprouts significantly decreased prostate cancer risk.
- Allium vegetables: A systematic literature search identified 9 studies involving over 130 000 participants which found that regular intake of allium vegetables – especially garlic – significantly decreased the risk of prostate cancer. Other members of the allium family include onions, leeks, shallots and chives.
- Physical activity: Regular exercise decreases the risk of prostate cancer, especially advanced cases.
… and then I woke up. Not in 24 years of clinical practice have I seen a client whose GP told them what they can do to reduce their risk of prostate cancer. And nowhere on PCFA’s website are prevention strategies discussed; their research programs are all focused on improving diagnosis and treatment options rather than saving men from the trauma of a prostate cancer diagnosis in the first place.
All in all, Prostate Cancer Awareness Month is yet another missed opportunity to educate the public on how to take responsibility for their own health and implement simple lifestyle changes that not only reduce the risk of this one disease, but improve overall well-being and quality of life.
I can’t think of one good reason why men should #GetChecked in September, or any other month for that matter, unless they are going to see a health professional who is well-informed enough to talk them through the risks and benefits of prostate cancer screening (or screening for any other type of cancer, for that matter) and help them to develop a plan to minimise their personal risk of developing prostate cancer.
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