Previous imaging findings of breast cancers that occurred in combined screening negatives

Purpose To retrospectively evaluate previous imaging findings of breast cancers that occurred in women whose combined screening using both mammography and ultrasonography was negative. Materials and methods A search of the institutional database identified 65 patients with breast cancers who had comparable previous negative screening mammography and ultrasonography (BI-RADS category 1 or 2) within 2 years. We classified each case as true or false negative. The previous imaging findings and the final outcome were analyzed. Results Among 65 cases, 42 (65%) were true negatives, 23 (35%) were false negatives. The abnormalities of false negatives were underestimated in 16 (70%) and unrecognized in 7 (30%). The findings were calcifications ( n = 8) or a mass ( n = 6) on mammography, a mass ( n = 5) or a non-mass ( n = 3) on ultrasonography and a density on mammography correlated with non-mass on ultrasonography ( n = 1). Ductal carcinoma in situ among false and true negatives accounted for 5 (22%) and 7 (17%), respectively. Symptomatic cancers among false and true negatives were 6 (26%) and 13 (31%), respectively. Conclusion Breast cancers that rarely occurred in combined screening negatives are often retrospectively seen as minimal abnormalities on previous imaging studies.