Accuracy of Mammograms Varies Across Racial and Ethnic Groups

Factors associated with the imaging facility, rather than individual characteristics, may explain some of these differences.

The accuracy of diagnostic mammograms was different across racial and ethnic groups, according to results published in Cancer Epidemiology, Biomarkers & Prevention, a journal of the American Association for Cancer Research. The researchers suggested that differences in the imaging facilities the women used, rather than in the women themselves, may explain the variances. 

“Diagnostic mammography performance varied among the four racial/ethnic groups in this study,” wrote the lead author, Sarah J. Nyante, PhD, associate professor of radiology at the University of North Carolina School of Medicine. “Our findings indicate that factors associated with the imaging facility, rather than individual characteristics, may explain some of these differences.”

The researchers looked at the invasive cancer detection rate, which is the number of cancers that were actually detected after a woman received a positive mammogram assessment, indicating that cancer was present.  

They found that the detection rate for white women was 35.8 per 1,000 mammograms, 31.6 for Asian/Pacific Islander women, 29.5 for non-Hispanic Black women, and 22.3 for Hispanics. 

The positive predictive value, which gauges accuracy, was highest among non-Hispanic whites at 27.8, followed by Asian/Pacific Islanders at 24.3, non-Hispanic Blacks at 23.4, and Hispanics at 19.4.

Asian/Pacific Islander women were the most likely to receive a false-positive report, indicating that a cancer is present when one isn’t actually there, and non-Hispanic Black women were most likely to receive a false-negative report, although this finding was not statistically significant. 

“Additional efforts are needed to identify the specific structural inequities that lead to disparities in diagnostic mammography performance. Enacting system‐level interventions to address those inequities has the potential to reduce some of the disparities we observed in this study,” Dr. Nyante wrote. 

The study provides a basis for considering the role of the diagnostic facility in women’s breast cancer treatment and suggests that further studies that provide the basis for mammography recommendations must include diverse patient populations, Dr. Nyante said. 

“Examining differences in diagnostic digital mammography performance and tumor characteristic outcomes by race and ethnicity may help us understand why disparities in cancer detection and quality of care persist for some demographic groups,” she said. 

In this study, Dr. Nyante and colleagues examined the results of 267,868 diagnostic mammograms performed at 98 facilities in the Breast Cancer Surveillance Consortium between 2005 and 2017. The researchers used Breast Imaging and Reporting Data Systems (BI-RADS) data to identify positive (malignant) and negative (benign) results. The racial distribution of the women whose mammograms were studied was 70 percent non-Hispanic white; 13 percent non-Hispanic Black; 10 percent Asian/Pacific Islander; and 7 percent Hispanic. 

There were also differences in the tumors detected through the diagnostic mammograms. Overall, Asian/Pacific Islander women had the largest proportion of ductal carcinoma in situ (DCIS), a noninvasive subtype. Meanwhile, Black women were more likely to be diagnosed at a later stage and higher tumor grade. As previous research has shown, they were also more likely to be diagnosed with the aggressive triple-negative breast cancer subtype.