Abstract
Background Annually about 1,700,000 women undergo breast biopsies with an estimated cost of $3.5 billion. About 80% of women are diagnosed with benign conditions (BCs). Other concerns are psychological impact and possible complications of radiographic evaluation of future mammograms. A recent report in the New York Times described the high rate of breast biopsies as diagnostic overkill, drastic and expensive. We report the preliminary findings on pathologic outcomes and predictive probability of sub-classifications of Breast Imaging Reporting and Data System-4 (BIRADS 4).
Methods We identified a total of 6,198 women with mammographic classification of BIRADS 4 between 1/1/2009-10/31/2011. So far, demographic, clinical and pathology data have been retrieved for a total of 624 women. Women were broadly stratified by their pathologic outcome into BCs of no clinical significance, proliferative conditions (PCs), and malignant lesions (MLs). Only final pathologic diagnosis was considered. All statistical analyses were performed using SAS v. 9.1.
Results A total of 157 women had opted against biopsy and therefore were excluded from further analysis. Of the remaining 467 women, 68.6% (n=322) were diagnosed with BCs, 9.6% (n=45) with PCs, and 21.3% (n=100) with MLs. Women diagnosed with MLs were older (63.5± 13.7) than women with PCs (61.5 ± 13.6) or women with BCs (56.2 ± 11.6) (P<.001). The difference in distributions of the other risk factors, breast density, family history, previous biopsy, use of postmenopausal hormones or body mass index, did not reach statistical significance among the 3 groups. A total of 104 women were sub-classified into 4A (n=65), 4B (n=16) and 4C (n=23). Our initial multivariate logistic regression suggested no statistically significant difference in the risk of breast cancer between women in 4A and 4B classification (P=.35). Final analysis suggested older age (OR=1.08, 95% CI 1.02–1.10, P=.01) was the best predictor of 4C. Our analysis yielded cancer predictive probability (PPV) of 0.13 (± 0.09) for 4A, 0.31 (± 0.16) for 4B and (0.76± 0.17) for 4C.
Discussion The rate of breast biopsy most likely will remain unchanged, given the present PPVs for 4A and 4B, unless other less invasive but as valid methods are developed.
