High risk women need ‘annual’ breast screening

Having a mammogram every year may benefit women at raised risk of breast cancer, new findings suggest today.

The general screening of women aged 40 to 49 years leads to a reduction in deaths from breast cancer, write Professor Stephen Duffy of Barts and The London School of Medicine and Dentistry, UK, and colleagues in the Lancet.

But the effect of family history is not clear, so the team looked at the effect of screening women younger than 50 who have a significant family history of the disease.

Women with several relatives who had breast cancer, or with relatives who had breast cancer early in life, can be at three times the risk of the general population.

A total of 6,710 at-risk women were enrolled at 76 centres in the UK and given mammography yearly for about four years. Of the 136 women who were diagnosed with breast cancer, 77 per cent were diagnosed at screening, 21 per cent due to symptoms between screenings, and two per cent due to symptoms after failing to attend their latest mammogram.

Compared with two external comparison groups, tumours in the study group were significantly smaller, less likely to have spread to the lymph nodes, and of more favourable grade. Overall, the predicted ten year mortality for these patients was significantly lower, by about 20 per cent.

The authors write: "Tumour size, node status, and grade are highly predictive of future death from breast cancer. We showed that these characteristics were significantly more favourable in tumours in this cohort than were those in the two independent comparison groups."

They calculate that two breast cancer deaths could be prevented for every 10,000 screens.

FH01 collaborative teams. Mammographic surveillance in women younger than 50 years who have a family history of breast cancer: tumour characteristics and projected effect on mortality in the prospective, single-arm, FH01 study. The Lancet, published online November 18, 2010.