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New study stirs up controversy (again) about breast cancer screening

The study provides more evidence that the benefits of regular mammogram screenings have been oversold to women. It’s also reigniting the sometimes ugly controversy over such screening.

“While no one can dismiss the possibility that screening may help a tiny number of women, there’s no doubt that it leads many, many more to be treated for breast cancer unnecessarily.”
REUTERS/Eric Gaillard

A study published last Wednesday in the New England Journal of Medicine (NEJM) provides more evidence that the benefits of regular mammogram screenings have been oversold to women.

It’s also reigniting the sometimes ugly controversy over such screening.

The study was conducted by Dr. Archie Blyer of St. Charles Health System in Oregon and Dr. H. Gilbert Welch of the Dartmouth Institute for Health Policy & Clinical Practice in New Hampshire. Welch, author of the book “Overdiagnosed: Making People Sick in the Pursuit of Health,” has long argued that too much of what is considered standard medical practice in the United States is either ineffective or, worse, harmful to our health.

For the NEJM study, Welch and Blyer used 32 years (1976 to 2008) of breast cancer data from the National Cancer Institute’s Surveillance, Epidemiology and End Results (SEER) program to determine the effectiveness of breast screening.

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What they found was disappointing, to say the least, as Welch explained in an opinion piece he wrote last week for the New York Times:

After correcting for underlying trends and the use of hormone replacement therapy [which has been linked to an increased risk of breast cancer], we found that the introduction of screening has been associated with about 1.5 million additional women receiving a diagnosis of early stage breast cancer.

That would be a good thing if it meant that 1.5 million fewer women had gotten a diagnosis of late-stage breast cancer. Then we could say that screening had advanced the time of diagnosis and provided the opportunity of reduced mortality for 1.5 million women.

But instead, we found that there were only around 0.1 million fewer women with a diagnosis of late-stage breast cancer. This discrepancy means there was a lot of overdiagnosis: more than a million women who were told they had early stage cancer — most of whom underwent surgery, chemotherapy or radiation — for a “cancer” that was never going to make them sick. Although it’s impossible to know which women these are, that’s some pretty serious harm.

But even more damaging is what these data suggest about the benefit of screening. If it does not advance the time of diagnosis of late-stage cancer, it won’t reduce mortality. In fact, we found no change in the number of women with life-threatening metastatic breast cancer.

Still, Welch adds, breast-cancer data offer women some good news, too. “Breast cancer mortality has fallen substantially in the United States and Europe,” he writes. “But it’s not about screening. It’s about treatment. Our therapies for breast cancer are simply better than they were 30 years ago.”

ACS: ‘Women should be fully informed’

Dr. J. Leonard Lichtenfeld, the deputy chief medical officer for the American Cancer Society, also wrote an opinion article about the study last week. Calling Blyer and Welch “highly regarded researchers,” he explained that although the ACS was not going to be changing its breast cancer screening recommendations any time soon, it recognizes that the society’s views on the subject are not the only legitimate ones.

As of today,  we continue to recommend women at average risk for breast cancer should have a screening mammogram every year beginning at age 40, along with a clinical breast exam.

What frequently gets “lost in the sauce” is that we also acknowledge the concerns that have been raised regarding the matter of over diagnosis and the benefits, risks and harms of screening mammograms. These are important, and women should be fully informed as they make a decision about what is right for them.

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Yes, we obviously believe screening should begin at age 40, but unlike some recent media reports suggest, we do realize that other respected experts do not agree with us.

‘First and foremost: Tell the truth’

Welch, however, argues that no matter how sincerely the medical community believed in annual mammograms and “the virtue of early diagnosis” in 1990, when widespread mammography screening was first implemented in the United States, it’s wrong to continue that policy.

“While no one can dismiss the possibility that screening may help a tiny number of women,” he writes, “there’s no doubt that it leads many, many more to be treated for breast cancer unnecessarily. Women have to decide for themselves about the benefit and harms.”

“First and foremost, tell the truth: women really do have a choice,” he adds.

You’ll find the NEJM study on the journal’s website. You can read the opinion pieces by Welch and Lichtenfeld at the New York Times and ACS websites, respectively.