According to research published inCancer Epidemiology, Biomarkers & Prevention, a journal for the American Association for Cancer Research, diagnostic mammograms were comparable across ethnic groups.
The racial disparities in breast cancer are well-documented, and research has identified multiple socioeconomic and biological factors as potential causes for the disparities, according to the study. Some aspects of breast cancer screening have also been examined, such as the timely receipt of screening mammograms, but less attention has been given to potential differences in the diagnostic mammography process.
If a screening mammogram has detected potential signs of breast cancer, Nyante said. Breast imaging is an important first step towards being diagnosed and developing the treatment pathway. It''s reasonable to think that differences at the beginning of treatment would affect future outcomes, she said.
Data from 267,868 diagnostic mammograms performed at 98 facilities in the Breast Cancer Surveillance Consortium between 2005 and 2017, were used by researchers to identify mammograms that radiologists considered to be positive (malignant) and likely negative (benign). The racial distribution of women whose mammograms were studied was 70 percent non-Hispanic white; 13 percent Asian/Pacific Islander; and 7% Hispanic.
The researchers calculated that the invasive cancer detection rate (the number of cancers detected after a mammogram, per 1,000 mammograms performed) was at the highest level among non-Hispanic whites (35.8), followed by Asian/Pacific Islander (31.6); non-Hispanic Black (29.5); and Hispanic (22.3).
The researchers investigated the positive predictive value, which measures cancer yield among positive mammograms, and found it was highest among non-Hispanic white (27.8); followed by Asian/Pacific Islander (24.3); non-Hispanic Black (23.4); and Hispanic (19.4).
Females from Asia/Pacific Islander were the most likely to receive a false-positive report. The false-positive rate per 1,000 mammograms was 169.2 for Asian/Pacific Islanders, 136.1 for Hispanics, 133.7 for Blacks, and 126.5 for whites.
Non-Hispanic Black women were most likely to receive a false-negative report. The false-negative rate per 1,000 mammograms was 4.6 for Blacks, 4.0 for whites, 3.3 for Asian/Pacific Islanders, and 2.6 for Hispanics.
Non-Hispanic Black women were the most likely to receive short-interval follow-up recommendations, with 31 percent of women recommended for further imaging within six months. By comparison, 22.1 percent of white women, 16.1 percent of Asian/Pacific Islander women, and 23.6 percent of Hispanic women received this recommendation.
Females from Asia/Pacific Islander had the highest percentage of ductal carcinoma in situ (DCIS), a noninvasive subtype. Despite their high tumor levels, black women were more likely to be diagnosed with later-stage tumors and higher tumor grade. These women were also more likely to be diagnosed with the aggressive triple-negative breast cancer subtype.
Nyante notes that controlling patient-level measurements did not explain the differences in performance statistics in this study, suggesting that the role of the diagnostic facility in womens breast cancer treatment should be further examined. This study emphasizes the importance of the inclusion of women from all backgrounds in clinical investigations, so that the population-level risks and benefits of mammography can be more evident.
According to Nyante, examining differences in diagnostic digital mammography performance and tumor characteristic outcomes based on race and ethnicity might help us understand why disparities in cancer detection and quality of care persist in some demographic groups.
Nyante observed some limitations to the study. While the study included both full-field digital mammograms and digital breast tomosynthesis (DBT) in recent years, DBT has become much more widely available. Therefore, the findings may not be entirely universal to the current imaging industry.