Predictive value of BI-RADS classification for breast imaging in women under age 50.

In this study, we assessed the positive-predictive value (PPV) of mammography and/or ultrasonography in women age 50 based on recommendations for biopsies and final pathology results. We performed a retrospective analysis of all mammography and ultrasonography reports issued from 9/2005 to 1/2007 resulting in biopsy among women aged 18-50 at a large county hospital. Data included demographics, imaging modality, breast density, type of finding, BI-RADS, and final pathology. Results were compared to women aged >50 at the same institution. Four hundred and seventy-five biopsies in 395 patients were reviewed. The PPV of BI-RADS 3 (n = 11) was 9.1%, BI-RADS 4 (n = 440) 5.9%, and BI-RADS 5 (n = 24) 66.7%. Forty three (9%) were malignant, of which 31 (6.5%) were invasive carcinomas and 12 (2.5%) were noninvasive. None of the biopsies on patients aged <30 were malignant. Recommended biopsies based on mammography alone were malignant in 20.2% (20/99) compared to 3.4% (7/205) for ultrasonography alone, and 8.9% (15/168) for both mammography and ultrasonography. Suspicious calcifications were malignant in 25% compared to 6.8% for masses/nodules and 3.6% for cysts. Lesions larger than 2 cm are more likely to be malignant (11.8%) than lesions between 1 and 2 cm (3.6%) or below 1 cm (4.3%). The PPV of the current screening modalities diminishes markedly in women under the age of 50 and even more below the age of 40. Calcifications and masses larger than 2 cm should be biopsied, but the current BI-RADS criteria may benefit from revision for other findings in young patients.