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For every life a mammogram saves, three other women will receive a life-altering medical version of TMI: too much information.

But is that risk still worth it?

A new British study has pointed to further limitations of the breast-cancer screening test, after an independent panel of scientists reviewed the findings of 11 clinical trials, going back several decades, as well as some more recent studies.

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In an article published today in the Lancet medical journal, the panel concluded that in Britain, for example, mammogram screening would save 1,300 lives every year, by catching cancer in its early stages.

But another 4,000 women would undergo unnecessary treatments such as radiation, chemotherapy and even mastectomies for cancers that would not have been otherwise detected or resulted in death.

The panel concluded, however, that screening programs should continue, but with the risks of being "over diagnosed" clearly laid out for women.

"We felt that the information given to women needs to be reviewed with our findings taken into account, so women are given an accurate picture of the benefits and harms," David Cameron, a professor at Edinburgh University was quoted as saying by the Guardian.

An awareness of the pros and cons of mammography has already triggered new controversial screening guidelines in Canada, which were announced in September. As The Globe and Mail's Andre Picard detailed, the screenings proposed that only postmenopausal women take the test and do so less often - and were supported by the science, despite the "early detection saves lives" mantra that so many women can recite by heart.

The recent British panel report adds weight to the argument that it's lousy science - and careless public policy - to sell a screening program as the perfect solution. It oversimplifies the complicated nature of a cancer diagnosis, and means that patients aren't empowered to make their own decisions and control their own care.

But, rational science is one thing; cancer is a disease made terrifying by its ability to lurk unnoticed until the damage is done.  One can hardly blame many women for preferring to be accidentally misdiagnosed than to have their cancer caught too late because they didn't get tested. Guardian columnist Emily Keller, who went through a bilateral mastectomy after an irregular mammogram detected cancer, questioned how doctors looking back at the clinical trial could know, by individual cases, which cancers will grow too slowly to amount to anything - and which ones won't. "Do you want to play those odds?" she asks. "I didn't."

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But that's the point: It's only armed with the best science available - one that doesn't oversimplify a complex disease - that patients can weigh their own odds.

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About the Author

Erin Anderssen writes about mental health, social policy and family issues. More

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