This week has brought James (23), Mark (35) and David (55). None of these men have any symptoms, and yet all were coming with deep concerns, all of them requesting a general health check, a 'medical MOT'. They've got their reasons. James has recently become a city banker. He now spends approximately 14 hours a day in an office, can no longer find the time to exercise, eats junk food at his desk and has put on 2 stone of weight. Ah, these poor bankers. Mark on the other hand is the healthy type. He cycles to work (lycra clad), eats organic, takes part in triathlons and shops with a re-usable hessian bag. But an equally healthy living friend has just been diagnosed with cancer and now he too feels vulnerable. David is a man in his 50's who has heard about prostate cancer. Such non-specific but deep rooted health concerns are becoming more and more common. They're encouraged by health horror stories from family, friends and from the media and deepened by searching on the internet. Privately, you can have screening blood tests, full body scans, computerised images of your brain, blood vessels or intestines - pretty much anything and everything that takes your fancy. But I wonder whether this is something that should be encouraged? The NHS doesn't think so, as apart from anything else it is about as cost-effective as a diamond encrusted toothbrush. But if money was unlimited, would it be a good idea for us to be fed through a scanner at regular intervals, just incase?
As far as I'm concerned, the answer should be a definite no, and I'll use David as an example of why. His request for a blood test to screen for prostate cancer was a perfectly sensible one. Prostate cancer is the second most common cause of cancer deaths in men in the UK, and it becomes more common over the age of 50. So, after a long discussion about the pro's and con's of testing, he went ahead and had the test. But it's no easy decision, as becomes apparent when you take a closer look at these pros and cons.
Pro's: If the test is negative, you'll feel reassured. If it's positive, you may pick up a cancer early, get treated quickly and not die. That's a pretty big pro. But here are the con's: 2 out of 3 men with a positive test will not have prostate cancer. This means that two thirds of men who go on to have a biopsy will turn out not to have cancer after all. When you know that a biopsy means having a probe with a needle attached inserted through your rectum and into your prostate this suddenly seems like a notable con. It doesn't get any better from here either, because if you are unluckily enough to have a positive biopsy result, there's often no way of telling whether the cancer that you have would ever cause you problems. Some do, some don't. So then you must decide whether you want to have treatment which can involve surgery (with the potential of nasty complications including impotence), radiotherapy and chemotherapy. If you decide not to, you have to live with the knowledge that you have a cancer that may or may not kill you. There's one further important con, and that's that a PSA test can miss a cancer and so can a biopsy.
The NHS has decided that the cons outweigh the pros in this case, and so whilst you can have the test if you ask for it, there is no national screening program in place. But this is just one disease. Imagine the possibilities for misadventure if we were to look for any conceivable problem with our health, year in and year out?
So whilst David had his test (it was negative), I tried to persuade James and Mark that in most cases, ignorance is bliss. I'm not sure that I did a great job of convincing them and I wouldn't be at all surprised if the private sector gets some revenue from these two. For me though, I'm just not in the business of looking for trouble...
Your comment about PSA testing is interesting.
ReplyDeleteHow would this compare to cervical screening? The sensitivity of which is only around 50% so half of those women with abnormal cells would be missed.
Of those testing positive, very few would actually go on to develop cancer if left untreated.
The test is instrusive to begin with, and the first line treatments involve burning a section of your cervix off.
But this is not only endorsed by the government, women are actively chased to attend.
Why the disparity?
I think you have to look beyond the sensitivity of a single screening smear test. Having 3 yearly checks increases the sensitivity. Looking more at population statistics, the figures show that if 80% of the population (women aged 25 - 65) can be screened a reduction in death rates of around 95 per cent is possible in the long term. Perhaps the biggest difference between prostate cancer and cervical cancer are the treatments available. To effectively treat early stage cervical changes, small, safe and comparatively minimally invasive excisions can be used. "Burning a section of your cervix off' is a dramatisation. Prostate cancer treatment is much more invasive, often requires a combination of surgery, chemotherapy, hormonal therapy and or radiotherapy and can give rise to serious side effects such as impotence. Given that the prognosis of prostate cancers is very variable and often completely uncertain, this is much harder to justify.
ReplyDeleteI think that a lot of the trouble (as I see it) with cervical screening lies in how the data are presented. You mention a 95% reduction in mortatlity rate. If only 1 person per million died in the first place, your figure still looks impressive, but is actually of little statistical importance.
ReplyDeleteIf you looks at the actual risk, rather than the relative risk however, an unscreened population has a 1.7% risk of mortality from cervical cancer, whereas a screened population has a risk of around 0.63%. (http://www.nature.com/bjc/journal/v91/n3/full/6602002a.html)
The relative risk reduction is 37% which sounds far more impressive than the actual 1.07% reduction.
Given this information I wonder how many women would still get tested? Perhaps that's why they aren't given it.
To do so would risk upsetting the apple cart, and most GPs would lose a valuable source of income due to the loss of incentive payments. These payments themselves, should the general population be more aware, would likely lead to a mistrust in the advice given by doctors, as they're essentially being paid to take a position.
If we then take a look at the ethics behind the screenign itself, WHO states that screening should be "an important health problem for the individual and community". As once of the rarer cancers, cervical cancer screening would seem to have failed at the first hurdle.
If also states that there should be a "suitable and acceptable screening test or examination." If the test were acceptable to the female population, then why is it necessary to pay GPs to coerce patients to attend?
Don't get me wrong - any loss of life it tragic, however attempting to screen an entire population, requiring an intimiate examination, to detect a rare disease doesn't seem practical, ethical or cost effective in my humble opinion.
Now as to HPV testing......