RESUMO
BACKGROUND: Mammography (MX) is a reliable modality for detection of breast cancer in asymptomatic women. Use of additional whole breast ultrasonography (US) for breast cancer screening is widely recognized, in particular in women with dense breast parenchyma. PURPOSE: To determine the subgroup of women, according to breast density and age, who receive most benefit from US following MX for detection of breast cancer in an asymptomatic condition. MATERIAL AND METHODS: The study was conducted in asymptomatic women who had non-fatty breast parenchyma using MX and US during January 2006 and December 2007. Mammographic breast density was classified as recommended by ACR BI-RADS lexicon. Non-fatty breast referred to D2, D3, and D4. US was performed by the same radiologists who interpreted MX with a handheld machine during the same visit. Data on demographics, cancer detection rate (CDR), and incremental cancer detection rate (ICDR) were analyzed using 95% confident interval (CI). RESULTS: Of 14,483 breast cancer screenings in women who had non-fatty breast density, 115 cancers were documented. The mean age of cancer patients was 49.6 years. Of 115 cancers, 105 were evidenced on images (31 with MX alone, 19 with US alone, and 55 with both MX and US). Overall CDR was 7.9 per 1000 examination (95% CI, 6.5-9.5). CDR for MX only (MX-CDR) was 6.5 per 1000 examinations (95% CI, 5.2-7.9). Additional US could significantly improve CDR (P < 0.001; 95% CI, 0.9-2.2); US-ICDR was 1.4 per 1000 examinations. According to age group, the group of 40-59 years had statistically significant improvement of ICDR (P < 0.001). The ICDR was highest in D4 breast density (D4) (US-ICDR = 2.5 per 1000 examinations). CONCLUSION: Use of US adjunct to MX for detection of breast cancer in asymptomatic non-fatty, average-risk women for detection of breast cancer is a promising diagnostic procedure. A significant benefit was documented, in particular, in women aged 40-59 years old, and in women with D4 breast density.
