Racial differences in false-positive mammogram rates: results from the ACRIN Digital Mammographic Imaging Screening Trial (DMIST).

BACKGROUND: Mammography screening reduces breast cancer mortality, but false-positive tests are common. Few studies have assessed racial differences in false-positive rates.
OBJECTIVES: We compared false-positive mammography rates for black and white women, and the effect of patient and facility characteristics on false positives. RESEARCH DESIGN AND
SUBJECTS: A prospective cohort study. From a sample of the American College of Radiology Imaging Network (ACRIN) Digital Mammographic Imaging Screening Trial (DMIST), we identified black/African American (N=3176) or white (N=26,446) women with no prior breast surgery or breast cancer. MEASURES: Race, demographics, and breast cancer risk factors were self-reported. Results of initial digital and film mammograms were assessed. False positives were defined as a positive mammogram (Breast Imaging Reporting and Data System category 0, 4, 5) with no cancer diagnosis within 15 months.
RESULTS: The false-positive rate for digital mammograms was 9.2% for black women compared with 7.8% for white women (P=0.009). After adjusting for age, black women had 17% increased odds of false-positive digital mammogram compared with whites (OR=1.17; 95% CI, 1.01-1.35; P=0.033). This association was attenuated after adjusting for patient factors, prior films, and study site (OR=1.04; 95% CI, 0.91-1.20; P=0.561). There was no difference in the occurrence of false positives by race for film mammography.
CONCLUSIONS: Black women had higher frequency of false-positive digital mammograms explained by lack of prior films and study site.The variation in the disparity between the established technique (film) and the new technology (digital) raises the possibility that racial differences in screening quality may be greatest for new technologies.