US women's attitudes to false-positive mammography results and detection of ductal carcinoma in situ: cross-sectional survey

Objective To determine women's attitudes and knowledge of both false-positi ve mammography results and the detection of ductal carcinoma in situ after screening mammography. Design Cross-sectional survey. Setting United States . Participants A total of 479 women aged 18 ro 97 years who did nor report a history of breast cancer. Main outcome measures Attitudes and knowledge a bout false-positive results and the detection of ductal carcinoma in situ a fter screening mammography. Results Women were aware that false-positive re sults do occur. Their median estimate of the false-positive rate for 10 yea rs of annual screening was 20% (25th percentile estimate, 10%; 75th percent ile estimate, 45%). The women were highly tolerant of false-positive result s: 63% thought that 500 or more false-positives per life saved was reasonab le, and 37% would tolerate a rate of 10,000 or more. Women who had had a fa lse-positive result (n = 76) expressed the same high tolerance: 30 (39%) wo uld tolerate 10,000 or more false-positives. In all, 62% of women did not w ant to take false-positive results into account when deciding about screeni ng. Only 8% of women thought that mammography could harm a woman without br east cancer, and 94% doubted the possibility of nonprogressive breast cance rs. Few had heard of ductal carcinoma in situ, a cancer that may not progre ss, but when informed, 60% of women wanted ro take into account the possibi lity of it being detected when deciding about screening. Conclusions Women are aware of false-positive results and seem to view them as an acceptable consequence of screening mammography. In contrast, most women are unaware t hat screening can detect cancers that may never progress but think that suc h information would be relevant. Education should perhaps focus less on fal se-positive results and more on the less-familiar outcome of die detection of ductal carcinoma in situ.