Mammograms: For 1 life saved, 3 overtreated

Associated Press

LONDON

Breast-cancer screening for women over age 50 saves lives, an independent panel in Britain has concluded, confirming findings in U.S. and other studies.

But that screening comes with a cost: The review found that for every life saved, roughly three other women were overdiagnosed, meaning they were unnecessarily treated for a cancer that never would have threatened their lives.

The expert panel was commissioned by Cancer Research U.K. and Britain’s department of health and analyzed evidence from 11 trials in Canada, Sweden, the U.K. and the U.S.

In Britain, mammograms usually are offered to women age 50 to 70 every three years as part of the state-funded breast-cancer screening program.

Scientists said the British program saves about 1,300 women every year from dying of breast cancer while about 4,000 women are overdiagnosed. By that term, experts mean women treated for cancers that grow too slowly to ever put their lives at risk. This is different from another screening problem: false alarms, which occur when suspicious mammograms lead to biopsies and follow-up tests to rule out cancers that were not present. The study did not look at the false-alarm rate.

“It’s clear that screening saves lives,” said Harpal Kumar, chief executive of Cancer Research U.K. “But some cancers will be treated that would never have caused any harm, and unfortunately, we can’t yet tell which cancers are harmful and which are not.”

The review was published online today in the Lancet journal.

In the U.S., a government-appointed task force of experts recommends women at average risk of cancer get mammograms every two years starting at age 50.

But the American Cancer Society and other groups advise women to get annual mammograms starting at age 40.