Accuracy of diagnostic mammography at facilities serving vulnerable women

Abstract

Background: Breast cancer missed on diagnostic mammography may contribute to delayed diagnoses, whereas false-positive results may lead to unnecessary invasive procedures. Whether accuracy of diagnostic mammography at facilities serving vulnerable women differs from other facilities is unknown.

Objective: To compare the interpretive performance of diagnostic mammography at facilities serving vulnerable women to those serving nonvulnerable women.

Design: We examined 168,251 diagnostic mammograms performed at Breast Cancer Surveillance Consortium facilities from 1999 to 2005. We used hierarchical logistic regression to compare sensitivity, false positive rates, and cancer detection rates.

Subjects: Women aged between 40 and 80 years underwent diagnostic mammography to evaluate an abnormal screening mammogram or breast problem.

Measures: Facilities were assigned vulnerability indices according to the populations served based on the proportion of mammograms performed on women with lower educational attainment, racial/ethnic minority status, limited household income, or rural residences.

Results: Sensitivity of diagnostic mammography did not vary significantly across vulnerability indices adjusted for patient-level characteristics, but false-positive rates for diagnostic mammography examinations to evaluate a breast problem were higher at facilities serving vulnerable women defined as those with lower educational attainment (odds ratio [OR], 1.39; 95% confidence interval [CI]: 1.08, 1.79); racial/ethnic minorities (OR, 1.32; 95% CI: 0.98, 1.76); limited income (OR, 1.34; 95% CI: 1.08, 1.66); and rural residence (OR, 1.55; 95% CI: 1.27, 1.88).

Conclusions: Diagnostic mammography to evaluate a breast problem at facilities serving vulnerable women had higher false positive rates than at facilities serving nonvulnerable women. This may reflect concerns that vulnerable populations may be less likely to follow-up after abnormal diagnostic mammography or concerns that such populations have higher cancer prevalence.