The problem with early detection of disease in medicine

Medicine is presented as being highly scientific. This is until information comes out which questions certain assumptions that underpin the practice of medicine.

One of the mantras of modern medicine is that early detection is good. This seems logical enough.

However there is an underlying assumption. That is that there will be a worsening of the condition if it is not detected and that treatment will improve the situation. What would happen if this were not the case? People would have treatment that they did not need and at best would not be better for it and at worst may suffer complications of the treatment.

Surely that is not the case you might be thinking. We have clinical trials and research to guide us. Unfortunately it is the case far more often than we think.

The best (or worst) example is with prostate testing. Last year the inventor of the PSA test wrote in the New York Times that when it comes to screening for prostate cancer the test was like flipping a coin.  There are also studies, which have concluded that for every one man, whose life is “saved” by screening, some 48 men have unnecessary surgery and many suffer impotence and incontinence as a result of this surgery. These men live no longer and their quality of life is impaired.

All this occurs because as soon as a raised PSA is found it will be acted on. Hence the case against screening and hence not “finding” levels to act on. It is important to note that screening involves testing people with no symptoms and no indication of disease. This is separate from investigating people with symptoms.

More evidence has now emerged. A study of 20,000 men aged 55 to 74 over an 11-year period showed that there was no benefit in annual screening. Some 80% of these men had an initial reading of less than three. After 11 years only 1% developed aggressive cancer and only 23 (0.15%) had died.

Doing a test once every eight years would see a reduction of 50% in the number of biopsies done. It would also reduce the number of prostate surgeries done needlessly although this number was not quantified.

A 20 year trial of 9,000 men published in the BMJ showed no difference in death rates in men who had regular screening compared to those who did not. The study concluded that the risk of over detection and overtreatment in screening is considerable.

The man who has his life “saved” will tell everyone. The man whose quality of life is reduced by needless surgery will not and (perhaps just as well) may not even know his fate.

There are other examples of how over diagnosing exposes many people to needless treatment. A new book has been published on this topic called, Overdiagnosed: Making People Sick in the Pursuit of Health.

Around 1,600 mammograms need to be done to find one breast cancer that would not otherwise have been found. For women aged 40-49 some 19,000 mammograms will have to be done and 650 women undergo unnecessary surgery and biopsies for the same one cancer to be picked up.

In skin cancer the number of moles removed from the skin per skin cancer confirmed has quadrupled in 25 years.

Mass screening is seen as “good” and there are constant calls for more funding for it. The programs attract a “saintly” aura and any questioning will be met with shrill criticism and hostile accusations from the screening industry.

Medical tests have benefits but also costs. The current belief that more is better is not correct. When we are operating on 48 people so one person has a benefit we need to be far more seriously questioning of what we are doing than is currently the case.

Joe Kosterich is a physician in Australia who blogs at Dr. Joe Today.

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  • http://www.facebook.com/people/Steven-Reznick/100000549195050 Steven Reznick

    This is all good food for thought except if you are the one individual whose life is saved and their loved ones and family. I tell the anecdote of early in my career taking annual chest x rays on people who smoked tobacco. In my practice of 3000 adult patients we found 2-3 peripheral carcinomas per year which were resected and ” saved” the patients life. When expert panels spoke against routine CXR’s the practice was eliminated but you keep wondering about those 2-3 patients and their loved ones. Now with all the confusing data on CT scans and lung cancer the issue is even more confusing with the testing being more expensive and exposing individuals to more radiation while detecting more false positives that require costly testing and intervention.
    I blame much of the problem on the 24 hour news cycle and social media requiring instant reporting and gratification. No longer do procedures or research  get discussed in research journals and at conferences with months for researchers and clinicians to comment before a consensus panel meets and issues guidelines. Everything is immediate. This creates a feeding frenzy created by people who do not have the training to understand statistical research leading to word of mouth consensus on testing. The PSA is just such a test as were homocysteine levels and possibly Vitamin D levels. Med Malpractice in the USA and the strong trial bar further exacerbate the problem.

    • Joe Kosterich

      It is good to be the one individual. Less so to be one of the people who have needless surgery or procedures and pointless stress. The question is how many people is it acceptable to harm in the quest to help one person? I do not claim to have the answer but the question still needs to be put

  • Anonymous

    I’m prejudiced because my father died three weeks ago from aggressive prostate cancer (Gleeson 9). He had regular PSA tests, but unfortunately his doctor didn’t notice his number going up for three years because he was busy investigating his GERD and making sure his heart was okay. I’m also disappointed that nobody in the family mentioned that his father and uncle had the disease. It was considered “too private to discuss.” All tragic mistakes.

    So get the simple tests done, and then watch the results. Don’t just file them. At least my father called his one male cousin, nagged him, and he was diagnosed in time. His grandchild will get to know her Grandpa.

  • eric_Lf

    Speaking of assumptions… This post has an underlying assumption that once a smoke signal (in the case of PSA) is detected, the only treatment route is agressive pharmacological or surgial intervention (or both). That’s too black and white. With a good understanding of the strength of the signal, the therapeutic response could (in principle) be gradual and adapted to the diagnostic data. A slightly elevated PSA may warrant increased observation and lifestyle changes, a more threatening one (with convergent data from other diagnostic sources) should trigger the carpetbombing of modern oncology. I have no clue about the current treatment algorithms and the perverse incentives leading to over-treatment, but it seems sensible in all cases to gather more data through routine screenings … provided the therapeutic response is appropriate to the findings.

  • Anonymous

    Bravo, Dr. Joe

    I will definitely read that book and have read other reports, clinical studies where over detection and over treatment is part of the huge unnecessary cost in medical care.  I believe it also interfers with real prevention by calling it prevention.  The real prevention of diet and exercise.  The one comment about vitamin D levels being lumped into unnecessary screening I believe is wrong. Blood levels may not be that reflective of how the D is absorbed or used but it makes people more aware that they need to supplement this  (a hormone really).  Studies have been ongoing for years and there are now recognized by even the medical community even though they don’t make money on Vitamin D.     

    Personally, I remember when the first bone scans were done.  My doc said “we didn’t do this study until now because we didn’t have a drug to treat osteoporosis.  Of course no one was checking nutrient consumption with regard to bones as this is not profitable. Mine showed osteopenia so I was started on a biphsophonate.  Had it again and no change.  Then I found out biphsophonates worked and stopped, even before all the latest fracture info.  I started eating better, taking bone supplements and adjusting them as new information came out.  I have had ultrasound tests at health fairs and my bones are in good shape.  But, according to my doc, that is not the gold standard even though I found several studies that showed it was comparable. I will get one, but I still won’t take biphsophonates.   

    Lots of money in Medicine to be made in screening and the subsequent surgeries and drugs.  Lots of money to be lost in Medicine and Big Ag if we ate right and exercised .

    • Joe Kosterich

       The more tests you do the greater the chance of finding “something” which then needs more tests to sort out.All good for the medical industry but expensive and of far less benefit than is claimed

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