Treating women who have had a false positive mammography screening (detecting cancer where there is none) is a third of the cost of providing screening for all women, Swedish researchers have discovered.

The inaccuracy of mammograms has been well recorded, but research has never before looked into the anguish, and the cost, involved for the women wrongly believing they have breast cancer.

Researchers from South Hospital in Stockholm monitored 352 women who had false positive readings. They made 1,112 visits to doctors, had 397 biopsies, 187 follow up mammograms and 90 surgical biopsies before being pronounced clear of cancer. Even after six months, only 64 per cent had been given a clean bill of health.

The process cost £250,000, and women under the "danger age" of 50 accounted for 41 per cent of these costs.

Researchers point out that these costs, extrapolated out, account for a third of the total cost of providing screening in the first place.

Their findings provide a potent argument against the recommendation of the Swedish health authorities that all women aged between 40 and 74 years should be screened between every 18 months and two years.