the u.s. spends $ 4billion -lrb- £ 2.7 billion -rrb- a year on unnecessary medical costs due to mammograms generating false alarms and on treatment for breast tumors unlikely to cause problems , a new report has revealed .
the study , published in the health affairs journal on monday , has estimated the figure for women aged 40 to 59 .
it is made up of $ 2.8 bn attributed to breast cancer overdiagnosis - treatment of tumors that grow slowly .