Column: Evolving Cancer Screening Guidelines

[Opinion column written by Dr. Michael R. Weitekamp MD, M.H.A., Chief of Staff, Bermuda Hospitals Board]

The recent public, political and social media backlash against the change in mammogram screening guidelines issued by the United States Preventive Services Taskforce [USPSTF] and adopted within the Standard Health Benefit [SHB - formally known as the Standard Hospital Benefit] for Bermuda is understandable.

Just the word “cancer” may invoke a very personal and visceral reaction of suffering, early death and concern for those we might leave behind.

An identified cancer is tragic enough when worrisome symptoms bring us to the doctor and those symptoms then prompt the testing which leads to the diagnosis.

But imagine you are perfectly healthy, happy, symptom-free and going about your busy, hopefully fulfilled life, when a screening test comes back as “suspicious” and your doctor now recommends some follow-up testing.

Suddenly you are no longer well, you have become a patient.

Even if the screening test turns out to be a false alarm – as many of them will – survey studies have shown that many people suffer heightened and long-lasting psychological symptoms, including anxiety and depression from such encounters with the health system. And as the sensitivity of various screening tests improves – including digital mammography, ultrasound, MRI, certain blood tests, etc. – the risk of both false positives and genuinely abnormal findings – i.e. “true positives” continues to rise – although these ‘true positives’ might not necessarily be life-threatening. We are transforming more and more healthy people into patients.

This might be a good thing if the medical community always knew what to do with what is found and if the natural history of every abnormal finding was fully understood.

Unfortunately, the purported benefits of early screening and early diagnosis are increasingly being called into question. Some very good data and thoughtful scientists interpreting that data have gone so far as to say we are in the midst of an epidemic of “over-diagnosis”.

What is “over-diagnosis”?

It occurs when you are diagnosed with something that was never going to cause you symptoms or shorten your life, and yet once diagnosed, both you and your physicians feel obligated to do something about it.

When universal screening programs target people without symptoms and lead to “over-diagnosis” they are doing more harm than good. In other words, rather than saving lives, they may be shortening some and adversely effecting the quality of many more.

This is why you have seen changes in the screening guidelines of most advanced jurisdictions and almost invariably these changes are to less aggressive screening for the reasons mentioned above.

Sticking just with mammogram screening for the moment, the official public guidelines in the US have been for every other year screening in women of average risk, beginning at age 40 through age 74 since 2009. Just this year the US is proposing changing the age to commence screening for average risk women to 50 years.

The United Kingdom, Australia and Canada already recommend screening only every 2-3 years. Sweden is on the verge of recommending the elimination entirely of routine, population-based screening for average risk women by mammography due to the failure of studies to demonstrate improved outcomes and due to the demonstrable harm that can be attributed to excessive screening.

It is patent nonsense to suggest that all these professionals and public health authorities are ignorant of the truth and insensitive to the needs of the average person. They are basing decisions on the best outcome data available.

Even a widely held assumption as fundamental as “early and frequent mammograms save lives” has been called into question for a number of reasons.

First, even the most optimistic estimates, based on studies of over one half million women over many years and many jurisdictions show that you must screen over 2000 average risk women for at least 10 years to potentially demonstrate one life saved by screening. Yet, over those 10 years nearly half of the women will be subjected to the harm of a false alarm requiring additional testing, perhaps a biopsy and all the attendant psychological issues mentioned earlier.

Now we also are beginning to understand that some are being “over-diagnosed” in the sense that some of the “cancers” being discovered are not inherently aggressive and may never have caused symptoms or death if left “undiscovered.” Yet, due to lingering uncertainty, these patients often undergo surgery and radiation therapy, each with its own immediate and delayed risk elements. Indeed, the breast cancer-specific death rates are showing slow and steady improvement over recent decades in many parts of the world. However, research models cannot and do not attribute this phenomenon to more screening, but to the fact that treatments have improved for established breast cancers, that fewer women are prescribed the hormone estrogen at the time of menopause and that many of these early “cancers” being found and perhaps never destined to shorten someone’s life are now treated, thus making the statistics appear better than they actually are.

I don’t harbor any delusion that an opinion piece such as this will change the minds of anyone with strongly held beliefs, personal anecdotes or vested interest in the status quo. These are complicated questions and to quote H.L.Mencken, “for every complex problem there is an answer that is clear, simple and wrong.” However, I do believe that those who express strong opinions are obligated to provide supporting data. I spent the first 36 years of my medical career in an academic setting and we had a saying that I am quite fond of recalling at times such as these…. “In God We Trust…everyone else must bring data.”

So, guideline recommendations have changed for many diseases and they are likely to change with even greater frequency in the future as we learn more and more about the natural biology and history of certain cancers and more about the unique genetic predispositions of segments of a population. It is very important to realize that population screening guidelines are directed at primary care providers and at individuals at average risk and without symptoms. Such guidelines are not meant to dictate every circumstance and nuance of clinical reasoning and risk. When in doubt, I would encourage anyone to speak with their physician and to be willing to ask question and to educate themselves. Please remember, above all else, that your long-term health and wellbeing depends so much more on your day-to-day choices regarding how you eat, sleep, drive, move, smile and socialize than on any medical test that you might choose to consent to.

For those interested in additional reading that touches on this issue and much more in an informative and entertaining fashion I highly recommend the book “Overdiagnosed: Making People Sick in the Pursuit of Health” by Drs H. Gilbert Welch and Lisa Schwartz.

For anyone interested in finding more information on any number of health issues that are framed in terms of the number of persons needed to treat [or screen] to help one person, contrasted with the number needed to “harm” by the same intervention, simply try out the web-site entitled TheNNT.com. This site is run by a group of physicians who developed a rating system to evaluate therapies or diagnostic interventions for patients based on potential harms and the desired outcomes….very informative and a great resource for truly informed consent and shared decision making with patients.

- Dr. Michael R. Weitekamp

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