Combined screening with mammography and ultrasound in a population-based screening program

Objectives: To compare the performance of screening with mammography combined with ultrasound versus mammography alone in women at average risk for breast cancer. Methods: 66,680 women underwent physician-performed ultrasound as an adjunct to screening mammography. Histological results and follow-up at one year were used as reference standard for sensitivity. Main outcome measures were cancer detection rate, sensitivity, recall rate, biopsy rate, and positive predictive value of biopsy for combined screening with mammography plus ultrasound versus mammography alone. Results: The overall sensitivity of mammography only was 61.5% in women with dense breasts and 86.6% in women with non-dense breasts. The sensitivity of mammography plus ultrasound combined was 81.3% in women with dense breasts and 95.0% in women with non-dense breasts. Adjunctive ultrasound increased the recall rate from 10.5 to 16.5 per 1000 women screened, and increased the biopsy rate from 6.3 to 9.3 per 1000 women screened. The positive predictive value of biopsy was 55.5% (95% CI 50.6%-60.3%) for mammography alone and 43.3 (95% CI 39.4%-47.3%) for combined mammography plus ultrasound. Conclusions: Supplemental ultrasound improves cancer detection in screening of women at average risk for breast cancer. Recall rates and biopsy rates can be kept within acceptable limits.