Diagnostic utility of combined ultrasonography and mammography in the evaluation of women with mammographically dense breasts.

To assess the diagnostic utility and additional cost of combined breast ultrasonography and mammography in the evaluation of asymptomatic women with mammographically dense breasts. Of 5108 asymptomatic women, who underwent mammography, 1754 had dense breasts (BI-RADS 3 or 4) and negative mammographic outcome. They were divided in 4 subgroups according to their age (<40 yrs; 40-49 yrs; 50-59 yrs; >59 yrs). Breast ultrasonography was performed immediately after mammography. Lesions detected at ultrasonography were examined cytologically/histologically. Mammograms from women, who were diagnosed carcinoma at ultrasonography, were reviewed by an external radiologist. Costs per diagnosed carcinoma and per examined woman were calculated on the basis of current regional charges. Mammographies (5108) were performed, 67 cancers were detected (cancer detection rate 13.1‰): mammography identified 55 carcinomas and ultrasonography performed in women with dense breasts identified 12 cancers (17.9% of all cancers detected, overall cancer detection rate 6.8‰). Ultrasonography identified a benign condition in 1567 out of 1754 women (89.3%) (in 925 absence of focal lesions; 438 simple cysts; 56 ductal ectasia; 148 benign solid lesions); 97 complex cysts, 52 lesions that could not be differentiated as liquid or solid lesions, and 38 solid lesions suspicious for malignancy in the remaining 187 out of 1754 patients (10.7%). Cytology/histology confirmed carcinoma in 12 women (overall biopsy rate 26.2‰, benign biopsy rate 19.4‰). The additional costs were: € 6,123.45 per detected cancer, € 41.89 per examined woman. Breast ultrasonography immediately after mammography in women with dense breasts is useful to avoid diagnostic delays and inconvenient medico-legal implications even though this procedure involves increased costs.