A 10 per cent increase in the number of women being screened resulted in a 16 per cent rise in the rate of cancers being diagnosed-and yet there was no difference in the number of deaths.
As Harvard University researchers point out, the principal function of mammography is to reduce deaths from breast cancer by detecting cancers early so they can be successfully treated.
But it's failing in this basic requirement, as the researchers discovered when they tracked the health of 16 million women aged from 40 years who had been screened. More than 53,000 breast cancers were diagnosed, but the vast majority were small, and, in fact, the number of larger, and potentially fatal, cancers that were detected declined.
Overall, mammography is not ideal for a mass screening programme, and would be best used on those at higher risk, they conclude.
(Source: JAMA Internal Medicine, 2015; doi: 10.1001/jamainternmed.2015.3056)