First Person: Why a "Vast" Mammogram Study May Do Harm

The study followed 90,000 women. It concluded that mammograms do not save lives. Critics disagree. So does my wife.

Breast cancer is the number one cancer afflicting women. The disease is often found through mammography.


It was 13 years ago, but I remember it as though it was 13 minutes ago.

My wife, Marsha, had a mammogram. Inconclusive, the report said. So she was called back for a follow-up.

I was at my office when the phone rang. In a shaky voice, Marsha repeated what the radiologist told her after the second screening: "Sure looks like cancer to me."

I thought of that moment when I saw the headline in this week's New York Times: "Vast Study Casts Doubts on Value of Mammograms." Many other media outlets picked up the story. The Daily Kos gave it this spin: "Vast Study, Mammograms Do More Harm Than Good?" CNN asserted: "Study: Mammograms Do Not Save Lives."

Marsha and I are neither scientists nor statisticians. But we both know that for her, the mammogram had tremendous value.

Because of the mammogram finding, she was diagnosed with stage II bilateral breast cancer: a tumor in each breast, one lymph node affected but no evidence of spread to other organs. She had lumpectomies, followed by six sessions of chemotherapy and a month of radiation.

Today, she is in good health.

The new study is impressive in scope: 90,000 Canadian women, followed for 25 years, with the results published in the BMJ, which summed it up this way: "Annual mammography in women aged 40-59 does not reduce mortality from breast cancer beyond that of physical examination or usual care when ... therapy for breast cancer is freely available."

The findings seem solid. Until you talk to some of the country's cancer experts.

"Everyone assumes it must be a good study. But it's the worst study ever done," says Daniel Kopans, a professor in the department of radiology at Harvard Medical School. In 1990, the doctors in charge of the Canadian study asked him to review the quality of mammography. "They had a lot of outdated machines," he reports. What's more, he says, the technologists who would perform the breast scans were not properly trained.

Kopans also claims that the study investigators gave breast exams to all participants before they were assigned to either the group that was to have mammograms or the control group. The study organizers likely "loaded the sides" by placing more women with advanced cancer in the screening group, he says. That would have boosted the survival rate for the women who did not have mammograms as part of the study.

Lead study author Anthony Miller vigorously rebuts Kopan's criticisms. Miller, a professor emeritus of cancer epidemiology at the University of Toronto's Dalla Lana School of Public Health, says the mammogram machines were "high quality." He defends the technique of the screeners and said an official assessment of study records "exonerated us" of the charge of stacking the deck.

It's all very confusing, especially because other studies have shown a reduction in deaths from breast cancer as a result of mammography. A 29-year research project in Sweden showed a 30 percent drop in mortality in women who were screened.

The continuing debate over the science of mammography—and the recent spate of screaming headlines that disparage mammograms—isn't merely academic. It has an impact on people's lives. Marisa Weiss, a breast oncologist in the Philadelphia area and founder of breastcancer.org, says the overburdened 21st-century woman, juggling work and family responsibilities, is definitely receptive to news that mammograms may not be necessary.

"Getting a mammogram every year is a pain in the ass. People would love not to get it. It's scary. Woman are saying, 'If [the medical profession] isn't so sure it's important, then I'm not going to go get it." In her practice, she's seen people "letting mammograms slip—instead of every year, every year and a half, every two years." Injecting doubt about diagnostic tools "can cloud people's thinking."

Breast cancer is the number one cancer afflicting women. And one of the "most common ways" breast cancer is found is through mammography, says Weiss. "It doesn't magically get treated without being found."

Then there is the study's claim that mammograms uncover small cancers that would not prove life threatening and would not require treatment. "My point of view is that you never want to miss a diagnosis," she says. "Missing a diagnosis of breast cancer is unacceptable because someone's life is at stake, and we don't yet know how to say it's okay to miss this cancer because it's not going to kill her."

Behind the raging debate and the blizzard of numbers in this and other studies, there are individuals like Marsha. Her dense breasts make it difficult if not impossible for her to find a lump by touch; doctors, too, rely on mammograms to assess her breasts. In fact, Anthony Miller told me that for women with "lumpy breasts," mammograms are a critical tool—a message that was not included in media coverage of his study.

I wondered what Marsha would make of all this, so I asked her. "From my perspective," she told me, "the mammogram saved my life."