Racial and Ethnic Variation in Diagnostic Mammography Performance among Women Reporting a Breast Lump

BACKGROUND

We evaluated diagnostic mammography among women with a breast lump to determine whether performance varied across racial and ethnic groups.

METHODS

This study included 51,014 diagnostic mammograms performed between 2005 and 2018 in the Breast Cancer Surveillance Consortium among Asian/Pacific Islander (12%), Black (7%), Hispanic/Latina (6%), and White (75%) women reporting a lump. Breast cancers occurring within 1 year were ascertained from cancer registry linkages. Multivariable regression was used to adjust performance statistic comparisons for breast cancer risk factors, mammogram modality, demographics, additional imaging, and imaging facility.

RESULTS

Cancer detection rates were highest among Asian/Pacific Islander [per 1,000 exams, 84.2 (95% confidence interval (CI): 72.0-98.2)] and Black women [81.4 (95% CI: 69.4-95.2)] and lowest among Hispanic/Latina women [42.9 (95% CI: 34.2-53.6)]. Positive predictive values (PPV) were higher among Black [37.0% (95% CI: 31.2-43.3)] and White [37.0% (95% CI: 30.0-44.6)] women and lowest among Hispanic/Latina women [22.0% (95% CI: 17.2-27.7)]. False-positive results were most common among Asian/Pacific Islander women [per 1,000 exams, 183.9 (95% CI: 126.7-259.2)] and lowest among White women [112.4 (95% CI: 86.1-145.5)]. After adjustment, false-positive and cancer detection rates remained higher for Asian/Pacific Islander and Black women (vs. Hispanic/Latina and White). Adjusted PPV was highest among Asian/Pacific Islander women.

CONCLUSIONS

Among women with a lump, Asian/Pacific Islander and Black women were more likely to have cancer detected and more likely to receive a false-positive result compared with White and Hispanic/Latina women.

IMPACT

Strategies for optimizing diagnostic mammography among women with a lump may vary by racial/ethnic group, but additional factors that influence performance differences need to be identified. See related In the Spotlight, p. 1479.

Does diagnostic mammography need to be a routine component of the initial evaluation of a breast symptom in women 30-39 years of age?

Diagnostic mammography is routinely ordered, along with targeted breast ultrasound, to evaluate breast symptoms in women 30-39 years of age. However, in this age group, mammography is often limited by breast density and the probability of detecting an occult malignancy is low. We sought to evaluate whether diagnostic mammography detected any new incidental malignancies in women aged 30-39 years presenting with focal breast symptoms. This retrospective study included women 30-39 years of age who had a diagnostic mammogram performed for focal breast symptoms at a single institution from 2002 to 2017. Descriptive analyses were performed to determine the rate of incidental mammographic findings outside of the region of the presenting symptom that 1) led to additional imaging and/or biopsies and 2) were found to be malignant. During the 16-year study period, 1770 evaluations were performed, of which 249 (14.1%) were found to have an additional incidental mammographic abnormality. Further diagnostic imaging was required in 211 (11.3%), core biopsy in 67 (3.8%), and excisional biopsy in 8 (0.5%). None of the mammographically detected incidental findings resulted in a new diagnosis of breast cancer. In the evaluation of focal benign breast symptoms in women 30-39 years of age, diagnostic mammography did not detect any new incidental malignancies outside of the area of interest, but instead led to additional unavailing imaging and biopsy procedures. The mammography component of the diagnostic evaluation of younger average-risk women may potentially be omitted if the presenting symptom is determined to be benign with ultrasound alone.

Evaluation of Palpable Breast Abnormalities

A palpable breast abnormality is one of the most common presenting clinical breast complaints. Although the majority of palpable abnormalities are benign, they are among the most common presenting symptoms of breast cancer, and those breast cancers detected symptomatically tend to have poorer prognosis than their screen-detected counterparts. Clinical breast examination is a vital part of the workup of palpable abnormalities. However, as physical exam features of most masses are not reliable for categorization of malignancy, imaging evaluation is necessary. Choice of imaging modality, which includes diagnostic mammography and breast ultrasound, is dependent upon patient age. Ultrasound is the primary imaging modality for evaluation of palpable masses in women younger than 30 years of age because of its high negative predictive value and sensitivity and lack of ionizing radiation. For women aged 30-39 years, ultrasound or mammography can be performed as the initial imaging evaluation, with ultrasound maintaining a high sensitivity in women younger than 40 years old. Mammography, often followed by ultrasound, is the recommended imaging evaluation sequence for women aged 40 and older. Utilization of advanced imaging modalities for evaluation of the palpable area of concern is not supported by evidence.