Effectiveness of Ultrasound for Breast Cancer Screening

To evaluate the effectiveness of ultrasound (US) for breast cancer screening, we conducted a retrospective survey of 856 breast cancer patients who were preoperatively examined by mammography (MMG) and US. Their average age was 54.7 years, with a range of 24 to 92 years. MMG revealed positive findings in 771 patients (90.1%), and negative findings in the remaining 85 patients (9.9%). Likewise, US revealed positive findings in 835 patients (97.5%), and negative findings in the remaining 21 patients (2.5%). Accordingly, the proportion of positive finding in US was significantly higher than that in MMG (chi-square test, p<0.0001).<br>The incidence of negative findings with MMG was inversely related to age : 5.8% for patients in their 70s, 5.7% for those in their 60s, 8.3% for those in their 50s, 11.1% for those in their 40s, and 26.2% for those in their 30s or younger, because of the higher breast density in younger women (chi-square test, p<0.0001). The incidence of positive findings was 99.4% for tumors 2.1 to 3.0 cm in size, 96.3% for those measuring 1.6 to 2.0 cm, 94.3% for those measuring 1.1 to 1.5 cm, and 75.4% for those less than or equal to 1.0 cm (chi-square test, p<0.0001). Among the 85 patients with negative findings by MMG, 70 (82.4%) were positive and 15 (17.6%) were negative by US. As findings of calcification by US, high echo spots plus a tumor lesion were observed in 59 patients (71.1%), high echo spots only were noted in 22 patients (26.5%), and high echo spots were not seen in 2 patients (2.4%).<br>In conclusion, parallel use of MMG and US is recommended for breast cancer screening, especially for women in their 50s or younger, to reduce the incidence of misdiagnosis.