Is Mammography As Much Of A Life-Saver As We Think?

By Karen Weintraub
Guest Blogger

Where do you come down on the great mammography debate?

Are you more comfortable knowing you’ve done everything you can to prevent breast cancer? Or are you annoyed by the pushiness of screening advocates, and convinced by data suggesting that it’s often over-diagnosed and over-treated?

A study published last week in the British Medical Journal added another twist to the longstanding debate, by suggesting that better treatments – not mammography – deserve credit for the drop in breast cancer deaths since the mid-1990s.

The study looked at pairs of northern European countries or regions; one that introduced universal screening many years before the other. Sweden, for instance, began universal screening in 1986, a dozen years before neighboring Norway. Researchers found breast cancer death rates were virtually identical on either side of the border, suggesting, they said, “that screening has not played a direct part in the reductions of breast cancer mortality.”

If this is true, we should be putting more emphasis on treatment advances, and far less on getting every woman over a certain age to get a mammogram.

That’s precisely what Dr. H. Gilbert Welch, professor of medicine at the Dartmouth Institute for Health Policy and Clinical Practice, thinks should happen.

There’s no question that mammography saves lives, Welch says, but it’s not as good a screen as most people think. About 2,500 women over 50 have to be screened every year for 10 years to save one life, he wrote in a New England Journal of Medicine editorial last year. Up to 1,000 of those women will have at least one false positive, and 5 to 15 of them will be treated needlessly for breast cancer they don’t have.

“We’ve exaggerated its effect grossly. And we haven’t acknowledged – in fact we’ve largely ignored – its harm,” Welch said. (Welch qualified his statement in a follow-up email: his complaint is with using mammography to screen a broad swath of people, most of whom have no symptoms. It is an appropriate test, he said, when used to examine women with suspicious lumps or other symptoms.)

Paradoxically, the more a test overdiagnoses a condition, the more popular it usually is, explained Welch, who co-wrote a book earlier this year called Overdiagnosed: Making People Sick in the Pursuit of Health. If you think your breast cancer screen saved your life, you’re going to believe in it devoutly and you’re going to tell everyone you know to get one.

There's plenty of institutional support for the pro-mammography position. Just last month, The American College of Obstetricians and Gynecologists issued new breast cancer screening guidelines that recommend mammography screening be offered annually to women beginning at age 40. (Previous ACOG guidelines recommended mammograms every one to two years starting at age 40 and annually beginning at age 50.)

But to Welch, the emphasis on mammography wastes resources that could be better spent saving lives with treatment. If encouraging women to get mammograms “is the most important thing we doctors do, we might as well go into a different business,” he said.

Dr. Daniel Kopans, a professor of radiology at Harvard Medical School and a senior radiologist at Massachusetts General Hospital, couldn’t disagree more with Welch’s conclusions.

Mammography saves lives – plain and simple. You can quibble over how many lives, but not with the conclusion, he says.

To Kopans, the question is whether we’re spending too much money on wasteful treatments. “Medical oncologists: they treat 100 women to benefit maybe 3-10 with their therapies,” he said.

Research in the United States shows breast cancer death rates dropping 5-7 years after the introduction of universal screening in the mid-1980s, he says. (You would expect a delay, because mammography catches some slow-growing tumors that would not have been noticed or caused health problems for some years.)

This European study was a scientific joke, he said. Some of the paired regions or countries were not easily comparable. And researchers looked too soon at death rates after universal screening was first introduced in the second part of the pair in the mid-1990s, he said.

Mammography isn’t perfect, Kopans agrees.

There’s no doubt that we treat some tumors that would have gone away on their own, or never turned lethal, he said. “We are not great – we’re not even good – at who needs the full treatment and who doesn’t. That’s a goal we’ve been pursuing for decades.”

And there are clearly cancers that can’t be cured even if caught early with mammograms, Kopans said.

But the more we know about cancer, the more we realize how complicated it is. There is still no breast cancer cure on the horizon. And so far, no better screen than mammography. “We’re going to chip away at” breast cancer, he said. “Until then, it’s insanity to not try to find it earlier.”

So, what’s a woman to do with all this information?

Welch says it comes down to personal choice.

Women who derive comfort or reassurance from a mammogram should be able to keep getting them, he said. And “women who don’t like mammography, or who feel guilty about the process should feel equally comfortable not pursuing mammography.”

Personally, I've had to fight for what I consider a “compromise” position. I got a baseline mammogram at 40, and planned to wait until 50 for another as long as I continue to have no symptoms. There’s no breast cancer in my family, and I have no known risk factors (which, according to the American Cancer Society include dense breasts, early start of period, heavy alcohol use, sedentary lifestyle).

My old OB agreed with this strategy. But the annual demands for mammograms continued. When I checked in at the OB’s office this morning, the nurse raised an eyebrow when I declined “my” mammogram. The new doctor I saw also balked. He admitted he didn’t know the right amount of time between screens for someone of my health status. But to a decade just seemed too long to wait.

What do you think?

Karen Weintraub is a freelance health and science writer based in Boston. She is the co-author of a forthcoming book on autism.