Over-diagnosis & Mammography

Over-diagnosis & Mammography 


Radiology Today (click for magazine cover)

June 2012

Overdiagnosis & Mammography 
By Kathy Hardy
Radiology Today
Vol. 13 No. 6 P. 24

A study finds over-diagnosis with increased screening, but there’s no way to determine which tumors do not need to be treated.

As radiologists, oncologists, patients, and advocates continue to wrestle with when mammography screening should begin, a new study suggests that with more views of breast tissue comes more potential overdiagnosis of breast cancer. The study, published in the Annals of Internal Medicine, concludes that mammography screening entails a substantial amount of overdiagnosis, which could lead women to undergo unnecessary and potentially harmful treatments.

Some believe the research casts more doubt on screening mammography, a modality still dealing with an identity crisis in the wake of the US Preventive Services Task Force’s 2009 recommendations suggesting that women at normal risk of breast cancer can reasonably delay mammography screening until they reach the age of 50. However many people in the breast imaging field still recommend mammograms for women at normal risk begin at age 40. The split creates a decision for referring physicians and patients regarding when to start breast cancer screening. Many breast radiologists contend that the idea of overdiagnosis and potentially unnecessary treatment of nonfatal cancer adds to the dilemma for doctors.

“This new epidemiological study tries to show that if we weren’t screening so much, we wouldn’t find as many unimportant tumors,” says Robin B. Shermis, MD, MPH, medical director of Ohio’s Toledo Hospital Breast Care Center. “This study deals in a theoretical world. In practicality, we can’t always tell which tumors have a potential aggressive biology when they are first detected. At initial detection, there is no way to identify whether or not a tumor is life threatening or will become life threatening.”

In blunter words, if you can’t differentiate between the tumors that will progress and kill a woman and the ones that will never harm her, how do you decide which tumors to treat? Breast radiologists assert that it’s too early to discuss what to do when mammography uncovers a tumor that fulfills the laboratory criteria of cancer but, if left alone, would never cause the patient any harm. They contend that, since science cannot accurately predict which tumors are harmless and which are more aggressive, it’s necessary to treat any tumor that's found as if it's deadly. That means surgical removal and sometimes radiation or chemotherapy.

“That’s exactly the problem,” says Rulla M. Tamimi, ScD, an associate professor of medicine at Harvard Medical School and a coauthor of the study. “Through imaging and pathology, we’re unable to determine the difference between fatal and nonfatal cancers. It’s important to have studies like this to get the debate going. Women should know about overdiagnosis.”

Finding Too Much?
The objective of the report, “Overdiagnosis of Invasive Breast Cancer Due to Mammography Screening: Results From the Norwegian Screening Program,” was to estimate the percentage of overdiagnosis of breast cancer attributable to mammography screening. This was done with a comparison of invasive breast cancer incidence with and without screening.

Tamimi says the data from Norway provided a unique opportunity to review data collected during the county-by-county introduction of a breast cancer screening program for women aged 50 to 69 that took place from 1996 to 2005. Researchers analyzed approximately 40,000 breast cancers, comparing cases found in counties where screenings were offered against counties where screenings were not yet offered. The study’s authors found that instances of invasive breast cancer increased 18% to 25% among participants who received screening mammography. They also found that between 1,169 and 1,948 of those women were overdiagnosed and received unnecessary treatments.

“In any screening program, there will be risks and benefits,” Tamimi says. “One of those risks is detecting cancers that, if left alone, will not cause mortality in the population of people screened.”

Carol H. Lee, MD, FACR, attending radiologist at Memorial Sloan-Kettering Cancer Center in New York and chair of the ACR’s Breast Imaging Commission Communications Committee, notes that the Norwegian study findings agree with those of the US Preventive Services Task Force recommendations, which suggested that there is a risk of overdiagnosis based on the number of women screened. However, she’s not suggesting that this means cancers found in breast tissue should be left alone.

“Saying [there is overdiagnosis], I know that screening with mammography saves lives,” Lee says. “The emphasis on overdiagnosis is too great.”

Lee contends that screening mammography shouldn’t decrease just because it may find cancers that are not deadly. “Does it make sense to stop finding cancers because some of them will not go on to be fatal?” she asks. Lee also challenges the use of the term “overdiagnosis,” saying instead that nonlethal breast cancer may be overtreated, not overdiagnosed.

“If a tumor meets the histologic criteria for being malignant, we treat them all as if they’re life threatening,” Lee says. “That’s the trade-off. We can’t tell whether it is life threatening.”

Treat What You Find
Looking at the study’s parameters, radiologist Stamatia Destounis, MD, managing partner of Elizabeth Wende Breast Care in Rochester, New York, questions the validity of the data, noting that “if you want to prove something invalid you can look at the data any way you want.” In particular, she points to the time span used to gather data for this study.

“With mammography, you need to study a program for more than nine years,” she says. “Imaging to detect breast cancer involves identification of subtle findings on mammography over time and long-term follow-up after breast cancer diagnosis to identify long-term benefits. We need more information on the women within the study and the control group over longer periods of time to identify a benefit.”

In her work with the ACR, Lee spends a great deal of time discussing the benefits of breast cancer screening. With the publicity that surrounds studies like this and the task force recommendations, she says referring physicians and women are unsure of what steps they should take when it comes to mammography.

“Another benefit of screening mammography relates to treatment options,” Lee says. “If you have a mammogram, there’s a chance that it will pick up a cancer that will never be life threatening, but you’ll still undergo surgery and possibly chemotherapy and/or radiation. However, there is also a chance that your life will be saved and treatment for the cancer will be less invasive because it is caught sooner. Which would you prefer? Different women will have different reactions.”

One of Lee’s arguments against studies like this and the task force recommendations is that with an epidemiological study you’re dealing with mathematical modeling rather than with actual practice. Shermis agrees that epidemiology has its place when studying breast cancer from a public health perspective. However, while the studies may provide insight to cost factors associated with unnecessary medical procedures and the stress associated with screening mammography follow-ups, they don’t address the human aspect of detecting the disease in women.

“Yes, there’s anxiety associated with any follow-up related to screening mammography findings, but that’s minimal compared to knowing you have a tumor and not treating it,” Shermis says. “An option would never be to leave a cancer alone. In addition, there’s much less stress involved and it’s much less expensive to treat a cancer when it’s small than after it has grown large.”

Confusing Referrers and Patients
Shermis and others believe these study results simply add to the already confusing amount of information disseminated in the past several years regarding screening mammography guidelines.

“This is just more misleading info,” Shermis says. “Women and referring physicians are confused enough. We were just starting to see a bounce back in screening mammography from the backlash that resulted when the task force findings were issued. Now, this study compounds the confusion.”

Identifying cancer is not a perfect science, Shermis notes. However, it is the job of breast imagers, oncologists, and surgeons to follow the proper steps required to make the best educated decision possible when it comes to breast cancer detection and ultimately a course of treatment.

“Nothing’s perfect,” he says, “but when you have the right people involved, it’s a relatively smooth process. Until we can identify cancers, we need to treat tumors that we find. Breast cancer screening has been profoundly successful in saving lives. As long as you have good standards for how to work up cancers and you follow them, you will have success.”

Radiologists, surgeons, and oncologists “all recognize that this tumor may not do anything,” Shermis adds. “None of us could look at a cancer and say we didn’t have to treat it. However, we’ve seen tiny cancers metastasize and large cancers do nothing. We’re not in a position to guess whether or not a tumor could lead to cancer.”

“The continuing dilemma for breast imagers is that we try to be as evidence-based as possible,” Lee says. “We’re not resting on our laurels. Clinical trials done with a half-million women over more than 20 years show us that mammography is still the gold standard for breast cancer screening. We need to stop picking apart the basic finding that mammography saves lives.”

Identifying Dangerous Tumors
Rather than a continued focus on the ethicality of breast cancer screening, Lee suggests that researchers look to finding a way to sort out which cancers have the potential to be lethal and which are safe to leave alone. Tamimi believes that’s where data from the Norwegian study can actually be used to help the evolution of breast screening guidelines. Pointing out instances of overdiagnosis and overtreatment of tumors found in the breast can help researchers determine where to focus next in the process of developing accurate breast cancer detection methods. Advancements in imaging technology and the use of ultrasound and MRI in scanning breast tissue continue to help locate tumors but, in many cases, also increase the incidence of false-positives. But there are other areas where further research could help identify what the technology is finding.

“They need to look at tumor characteristics and tumor markers and learn more about which traits are less aggressive,” Tamimi says.

“Many women aren’t even aware that overdiagnosis exists in breast cancer screening,” she adds. “The discussion started with prostate cancer, but more should be said regarding overdiagnosis in breast cancer. Women are being told they have a cancer, which comes with its own stress, and then they have to deal with treatment. They should really have a clear picture of whether or not what was found in their breasts is good or bad before making those decisions.”

For the immediate future, however, Tamimi understands how these findings can create confusion for women over time. “It’s disappointing to people to hear that screening mammography isn’t the tool that it’s been presented as,” Tamimi says. “Dialogue about overdiagnosis is important to get out there so that research and developments don’t stay stagnant.”

Tamimi says the Norwegian study serves as a starting point for more effective communication between physicians and patients regarding over-diagnosis, which she contends goes hand in hand with misdiagnosis.

Lee points out that while this study brings up the issue of too much screening and the potential for overdiagnosis that might come with that, at the same time state and federal governments are debating the legislation of mandatory breast density notification. Texas, Connecticut, and Virginia passed laws within the last two years that require radiologists to notify patients if they have dense breast tissue following routine screening mammography; other states, as well as the federal government, are considering similar measures this year. There is the belief that legislating dense breast notification could lead to more screening with ultrasound, MRI, and other imaging modalities, which could lead to more false-positives.

“On the one hand we’re saying there are too many false-positives and too much screening,” Lee says. “On the other hand, there is the breast density notification issue that will likely lead to more screening. As breast imagers we’re caught between two imperatives: screen less vs. screen more.”

While Lee recognizes that mammography is not perfect, it is the only screening tool that has been shown to decrease mortality from breast cancer. “The bottom line is that screening mammography saves lives,” she says.

— Kathy Hardy is a freelance writer based in Phoenixville, Pennsylvania. She is a frequent contributor to Radiology Today.

General Health Checkups and Medical Screening Tests—Do You Really Need Them?

By Dr. Mercola

Alan Cassels, a drug policy researcher at the University of Victoria in British Columbia, has written several books about the drug industry. His latest work is called Seeking Sickness: Medical Screening and the Misguided Hunt for Disease.
This book is loaded with helpful information about medical screening, and really focuses on an important topic, which is prevention.
It's been a longstanding passion of mine to prevent disease rather than to treat it, because it's so much easier to implement a preventive strategy. There is an enormous amount of effort and research invested in the traditional community into medical screening procedures.
The trouble is, conventional medicine views these medical tests as "prevention," when in fact there's nothing preventive about them at all. They're just diagnostic tools, and some aren't even all that accurate at that. Worse yet, some may be risky, and do more harm than good.

"I've been following the marketing tactics of the pharmaceutical industry for almost 18 years now," Cassels says. 
"I came upon screening partly because I started to see that a lot of people who ended up being put on certain regimes ended up there because they'd been through some screening regime – perhaps a screen for their blood cholesterol, a screen for their eyeball pressure, or even something simply as benign as screening for high blood pressure.
I started to look upstream from the pharmaceutical industry and really look at the kind of tactics that were used to entrap more and more people into drug regimes. And screening... is very pervasive."

To Screen, or Not to Screen?

A recent article in The Atlantic¹, written by Oklahoma physician John Henning Schumann, MD, brings up the issue of over-screening—medical tests that simply are not necessary, or worse, detrimental. He discusses the case of one of his patients, who brought in results obtained from a "medical screening fair" at her local church.
The test was advertised as a bargain at $129, but according to Dr. Schumann, it was a complete waste of money considering she didn't have any risk factors warranting the testing. Besides relieving her of some hard-earned money, all it did was make her anxious when she really didn't need to be.

"I love America and the free market. I love companies that make a buck with hard work and ingenuity..." he writes. "But I don't love when innocent people get fleeced in the name of bad medicine that pretends to be good. Worse yet, when it happens at church. Commercial screening companies fiendishly target churches to find parishioners looking for healthy bargains. If your local church is endorsing a "health screening fair," it must be good, right?"

Yes, churches, synagogues and other houses of worship have recently been targeted by the medical industry in an effort to increase business. This became woefully apparent last year, when the White House Office of Faith-Based and Neighborhood Partnerships, co-sponsored by the U.S. Health and Human Services, the Office of Minority Health, and the CDC, held an invitation-only, off the record call².
The focus of the call was on getting faith-based organizations to sponsor flu clinics with Walgreens. As an example, they cited a priest who stopped in the middle of mass to roll up his sleeve and get vaccinated, inspiring the rest of his parish to line up behind him. This has nothing to do with promoting good health. It's just another marketing shtick, and a potentially dangerous one at that. I'm sure the priest in question didn't stop to recount the many potential side effects before his flock took to the line to follow his lead.

"She didn't need these screening tests, and I'll tell you why," Dr. Schumann continues.
"As a non-smoking daily walker, her chance of having peripheral arterial disease (blockage of the leg arteries) is vanishingly small. The ultrasound of her abdomen, to search for an aneurysm of the aorta, is also a waste of money since her likelihood of having the condition borders on the absurd. The same is true for the ultrasound she received of her carotid arteries. In fact, the country's most influential (and controversial) authority on screening, the U.S. Preventive Services Task Force, recommends against all of the tests Mildred underwent as routine screening tests.

The broader issue on why excessive screening is bad is that it can lead to a cascade of obligatory follow-up costs down the line... Companies should not play on our fears to sell us unnecessary screening exams. When they do, we should be confident that we're better off not buying them."

Routine Health Checks Found to Have No Benefit

In related news, a recent study by the Cochrane Library³, the gold standard for independent medical reviews, found that:

"General health checks did not reduce morbidity or mortality, neither overall nor for cardiovascular or cancer causes, although the number of new diagnoses was increased. Important harmful outcomes, such as the number of follow-up diagnostic procedures or short term psychological effects, were often not studied or reported and many trials had methodological problems. With the large number of participants and deaths included, the long follow-up periods used, and considering that cardiovascular and cancer mortality were not reduced, general health checks are unlikely to be beneficial."

This may sound shocking to many, as general health checks are typically considered to be part and parcel of early disease detection and prevention. However, after reviewing the health outcomes of nearly 183,000 people, the researchers found that, in terms of making you live longer, getting regular health check-ups doesn't appear to make a difference...
Regular screening may however increase your drug use, and you may receive a diagnosis and treatment for a condition that might never have led to any symptoms or had any impact on your longevity. According to lead researcher Lasse Krogsbøll⁴ of The Nordic Cochrane Centre in Copenhagen, Denmark:

"What we're not saying is that doctors should stop carrying out tests or offering treatment when they suspect there may be a problem. But we do think that public healthcare initiatives that are systematically offering general health checks should be resisted."

This isn't the first time researchers have concluded we may be over-testing and over-treating. In fact, over the past few years this has become increasingly studied, and most analyses concur that more testing and more aggressive treatment does not translate into reduced mortality. Naturally, there's no way to make recommendations here that could apply to everyone or even most people. Evaluating your risk factors is one important factor of course, as stated in Dr. Schumann's article. Evaluating your symptoms is another. If you're asymptomatic, maintain a healthy, active lifestyle, and don't have any risk factors, perhaps signing up for a bunch of medical tests at your local church, "just in case," is not in your best interest.

Medical Screenings—Heavily Promoted to Increase Sales of Post-Screening Activity

Alan Cassels also has something to say about this:

"[S]o much of what we consider to be disease in the orthodox medicine world has been created, has been shaped, and has really been molded by the pharmaceutical industry," he says. "And very much what we consider to be medicine is determined by the kinds of things that end in what the drug industry calls the 'drug successful visit.' Not just anything that we potentially could be sick with, but anything that any healthy person could get.

And really, screening is about looking in healthy people to find signs of disease.

I want to distinguish right off the bat that when I'm talking about screening, I'm talking about people who have no symptoms, who are otherwise healthy, and who have really no reason to consult the doctor or being told, 'You need to be proactive. You need to seek out early signs of disease. That's a good thing to do to keep yourself healthy.' People that actually have symptoms – feel a lump or whatever – and then go in for a test, that's a diagnostic test. That's something different.

I'm talking about a screening test where you're taking otherwise healthy people and trying to find signs of disease in them."

Common Cancer Screens Can Do More Harm than Good

Much like myself, Cassels research has led him to seriously question common tests like mammography for breast cancer, and the PSA test for prostate cancer. In the interview above he explains:

"[O]ne thing that we know for sure is that a lot of the activity around screening makes a lot of money for a lot of people. One example might be the whole world of mammography... [W]e're telling healthy women who have no symptoms, 'Go in every year. From the day you turn 40, go in once a year, and have your breasts radiologically screened.'

What we're not telling women is that just the act of screening involves a whole downstream potential for harm and also involves huge amounts of certain medical resources in terms of the radiologist, the surgeons, and so on.

It's a huge industry. You might say, 'Well, what's wrong with that industry if it's actually saving lives?' Well, when you sit down, and you look at the number of women that have to be screened in order to have one woman benefit, it's actually quite shocking... The best studies (these are studies that are over 10-years long and done in Canada, the U.S., and in Europe), have found that you have to screen 2,100 women every year for 11 years to prevent one death. So, to answer the question, 'Is it lifesaving?' Yes. One in 2,100 women would benefit from being screened over an 11-year period.

But at the same time, of those 2,100 women, about 600 to 700 of them will have a false-positive. They will find something unusual or something abnormal, and that will require biopsies, open surgeries, mastectomies, and so on. Not to mention the psychological harm of inflicting a cancer scare... The problem is that you're generating a huge amount of activity to save one in 2,000 women. In the best-case scenario, you're causing 600 or 700 women to have huge amounts of procedure... It seems to me that it's an awfully high cost to pay to prevent one death.

And I think that there are many, many other things that we can do to try to reduce the risk of breast cancer in women rather than telling them to get their annual mammography screen."

The male version of mammography is the annual PSA test. It's a simple blood test that measures the level of an antigen in your blood. An elevated reading could indicate that you have prostate cancer, or are at increased risk of developing prostate cancer. Or not, as the PSA test is notoriously inaccurate...

"What most men aren't being told – this is from the research that I did – is when they're given that test, the likelihood of them finding cancer cells in their prostate are fairly high," Cassels explains.

"In fact, it's directly proportional to your age. If you live to be 60 or 70 years old, there's a good chance you're going to have a 60 percent chance of having some evidence of prostate cancer. You might say, 'Wow, if you've got prostate cancer, shouldn't you do something about it?'

Well, certainly with the PSA test and its lack of specificity and accuracy, you've got 60 or 70 percent of the male population that will develop prostate cancer in their lifetime. But only about three percent of men will die from prostate cancer.

What doctors have told me is that most men will die with prostate cancer, but not because of it. And that's really kind of a mindblowing concept for a lot of people, because they think what you're saying is that, 'I can have a cancer in my body and live a perfectly, long, and healthy life.' Absolutely.

One of the things that screening is good at is finding signs of disease. What it's not very good at is finding disease that matters. In this case, having an elevated PSA level could be caused by a whole range of things. And if you're otherwise asymptomatic, going down that line of getting tested will lead to biopsies, possibly surgery, other kinds of treatment including chemotherapy, and hormone therapy. At the end of the day, a lot of the men that go through that mill end up becoming incontinent or impotent because of the treatment."

Medical Science Rarely a Slam Dunk

In related news, a recent study⁵ by Dr. John Ioannidis of the Stanford School of Medicine in California warns against placing too much faith in medical studies showing very large effects of medical treatment (benefits or harms). The massive analysis tracked the fate of thousands of studies, from the effects demonstrated in the initial study, compared to the effects elucidated in subsequent trials.
Interestingly, in 90 percent of cases where "very large" effects were initially reported, such effects shrank or vanished altogether as subsequent studies were done to confirm the results. Dr. Ioannidis told Reuters⁶:

"Our analysis suggests it is better to wait to see if these very large effects get replicated or not... Keep some healthy skepticism about claims for silver bullets, perfect cures, and huge effects."

Typically, studies reporting very significant effects are based on smaller, less reliable experiments. This is because small trials are more likely to be skewed by chance alone. The authors also point out that studies showing very large effects rarely address mortality, and are more likely to address laboratory-defined efficacy. Alas, changes in lab values does not necessarily equate to improved health... Sometimes, this kind of efficacy could actually be disastrous.
Dr. Andrew Oxman of the Norwegian Knowledge Centre for the Health Services in Oslo, who wrote an editorial⁷ about the study, told Reuters⁸:

"'There are lots of examples where things start to be used and have entered the market based on surrogate outcomes and then actually proved harmful.' He mentioned the heart rhythm drugs encainide and flecainide, which for many years were given to people with acute heart attacks. But then trials showed they were actually bad for these patients. 'These drugs were by given well-meaning clinicians, but they actually killed more people than the Vietnam War did,' Oxman said.

Statins are another perfect example of this, as they are very effective at reducing your cholesterol level, yet wreak all sorts of havoc in your body while doing so. If you're not careful it may even lead to premature death. Your cholesterol numbers will probably be a-okay though, if that brings any relief to anyone, and your death will be chalked up to some other health problem.
According to Cassels:

"[W]hen you look at the big meta-analyses of statin drugs, there are about five major studies that have tens of thousands of patients in them... testing drugs like simvastatin or atorvastatin (Zocor or Lipitor). When you look at the totality of those studies, the one thing that you find is that the benefit, in terms of reduction in heart attack or stroke for people who haven't had a heart attack or stroke (we're talking primary prevention), is simply not there.

You can alter cholesterol quite easily using cholesterol-lowering drugs. But the question is, 'What's important? Having your cholesterol altered or reducing your risk and reducing the chance that you could have a heart attack?'

I think that the main thing that has happened... [is that] we focus on the numbers... when in fact, what really counts is whether you have a heart attack or stroke.

Of course, it takes long-term studies, five- and 10-year long studies, to determine whether drugs will prevent that. And certainly in the primary prevention population, you don't see any reductions. Women don't benefit from having their cholesterol altered with statins, and certainly [not] the elderly. Some of the newer research is showing that older people who have higher cholesterol actually have a protective effect from that."

Final Thoughts

Of the tens of thousands of treatments evaluated in Dr. Ioannidis study, only one stood out as a clear "slam dunk" in terms of the benefit of treatment. A respiratory intervention in newborns repeatedly demonstrated a reliable, very large drop in death rates. That really tells us something about "evidence-based medicine," doesn't it?
It's not at all as clear-cut as conventional doctors and health authorities would like us to believe. Today, I think many treatment recommendations, especially in terms of drugs and vaccines, are clearly premature and based on very flimsy evidence. The same applies to many of the medical screening tests available. The evidence of real benefit simply isn't there in many cases.

"I guess the summary statement is: go into the screening with your eyes wide open," Cassels says.

"And that is to say that it's not an emergency procedure. If you're being offered a screen of any sort whether it's a mental health screen, a screening of osteoporosis, for blood pressure, cholesterol, or for cancers, take the time to ask the questions. 'How could I be hurt by this screening?'

When you actually understand that a screening can potentially harm you, you might take a very different approach to rushing into it. You might take more time to actually do some research. And really when you do research, it's important that you look at independent sources of information.

... The United States Preventive Services Task Force—their stuff is all available on the Internet. In terms of the spectrum of trustworthiness, I would place that in the More Trustworthy category, as opposed to the other category, which might be those groups that stand to benefit from screening and over-promote and overpromise on screening's benefits. So, really, independent information is I think key, and knowing that screening can potentially harm you."

 http://www.youtube.com/watch?v=-oczZye3hpY

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