UK women invited to attend screening for breast cancer are three times as likely to be treated for a cancer that would never have harmed them as they are to have their lives saved, an expert panel has concluded.1

For every 10 000 women invited to mammography screening for 20 years between the ages of 50 and 70, the panel estimated that 43 deaths would be prevented and 129 women would be given a diagnosis (and most likely treated) who did not need treatment.

The panel’s calculation of the lives saved is close to that previously claimed by the NHS breast screening programme: 1300 a year. But 4000 women undergo treatment for a cancer that would not have harmed them.

The panel, assembled by the Department of Health for England and the charity Cancer Research UK, concluded that screening confers significant benefits and should continue but that clear communication to women of the harms and benefits was essential.

England’s national director for cancer, Mike Richards, said that he accepted the findings as “the best we’ve got” and that they would be incorporated into leaflets sent to women inviting them to be screened.

Cancer Research UK said that it advised women to continue attending screening. Harpal Kumar, the charity’s chief executive, said, “On balance, taking all the evidence into account, CRUK recommends that women go for breast …