The risk of false-positive mammograms has been reported in two modern screening studies. A study published in the New England Journal of Medicine in 1998 highlighted the problem of false-positive mammograms. While the overall conclusions were rather negative, some positive aspects can be pointed out from the data. Certainly, false-positives do contribute to the increased cost of screening for breast cancer because of the additional workup that an abnormal report requires. However, if the false-positive rate is too low, then real cancers will be missed.
False positives show that the radiologists are meticulous in their reading of mammograms.
Falsely negative mammograms are a much more serious problem. Both physicians and women must be aware of mammography's limitations. Clinical breast examination should be performed near the time of the mammogram to avoid missing a palpable lesion that mammography does not detect. Clinical breast examination should always be a companion to mammography screening. Guidelines for screening mammography vary.