How Cancer Screening Makes Healthy People Sick

Health and medicine explained.
Feb. 14 2014 8:08 AM

Misfearing Breast Cancer

More evidence that routine mammograms make healthy people sick.

mammogram.
Less than 7 percent of breast cancers are diagnosed in women younger than 40.

Photo by Jupiterimages/Thinkstock

This article originally appeared in The Last Word on Nothing.

What’s the No. 1 killer of women? It’s a question that practitioners asked every new patient at a clinic where physician Lisa Rosenbaum once worked, and she hasn’t forgotten the answer given to her by one middle-aged woman with high blood pressure and elevated blood lipids. “I know the right answer is heart disease,” the patient told Rosenbaum, “But I’m still going to say ‘breast cancer.’ ”

Rosenbaum recounts this experience in a perspective published this week in the New England Journal of Medicine, which follows on the heels of a long-term study published online this week in BMJ that found no benefit from screening mammography. The two papers make fine companions.

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The Rosenbaum commentary explores a phenomenon that Cass Sunstein dubbed “misfearing”—our human nature to fear instinctively, rather than factually. Rosenbaum’s patient’s first answer is correct—heart disease kills more women than all cancers combined, yet breast cancer seems to invoke far more fear among most women. “What is it about being at risk for heart disease that is emotionally dissonant for women?” Rosenbaum asks. “Might we view heart disease as the consequence of having done something bad, whereas to get breast cancer is to have something bad happen to you?”

I don’t know the answer to this question, but I suspect that Rosenbaum is onto something. Studies show that women—and doctors—grossly overestimate their risk of developing breast cancer and dying from it. One study published in the Journal of the National Cancer Institute found that women in their 40s overestimated, by a factor of 20, their risk of dying from breast cancer during the next decade. I have to think that the media is partly to blame.

Less than 7 percent of breast cancers are diagnosed in women younger than 40 (the median age at diagnosis is 61), but when the disease strikes younger women, it tends to be more aggressive and less responsive to treatment than it is in older women. Scary stories like those of Susan G. Komen, who died of breast cancer at age 36, invoke fear, and for good reason. Komen did not bring her cancer upon herself. Her disease was random, undeserved, and very aggressive. And if you flip through the women’s magazines during their October “breast cancer awareness” extravaganzas, most of the stories you’ll read are about beautiful young women like Komen who were diagnosed at a young age. The way to prevent such a fate, most of these stories will tell you, is obvious—screen early and often.

This solution is the only reasonable option if you think of breast cancer as a relentlessly progressive disease that will inevitably kill you if you don’t remove it in time. That story about breast cancer—I call it the “relentless progression” model—has truthiness on its side. It makes common sense and offers a measure of comfort: Every cancer can be cured if you just catch it in time.

There’s just one problem, as I’ve written here numerous times before—research has shown that the relentless progression model is wrong. Despite the one-size-fits-all name, breast cancer is not a single disease, and as the science of tumor biology has advanced, researchers have come to understand that not every breast-cancer cell is destined to become one of the life-threatening varieties. It’s only when cancer spreads to other parts of the body—a process called metastasis—that it becomes deadly, and it’s now clear that not every breast cancer is fated to leave the breast. If you detect an indolent cancer early, there’s no life to save.