Predictors of nonadherence to breast cancer screening guidelines in a United States urban comprehensive cancer center.

backgroundThis study aimed to identify predictors of nonadherence to breast cancer screening guidelines in an urban screening clinic among high- and average-risk women in the United States.

methodsWe reviewed records of 6090 women who received ≥2 screening mammograms over 2 years at the Karmanos Cancer Institute to examine how breast cancer risk and breast density were associated with guideline-concordant screening. Incongruent screening was defined as receiving supplemental imaging between screening mammograms for average-risk women, and as not receiving recommended supplemental imaging for high-risk women. We used t-tests and chi-square tests to examine bivariate associations with guideline-congruent screening, and probit regression to regress guideline-congruence unto breast cancer risk, breast density, and their interaction, controlling for age and race.

resultsIncongruent screening was more likely among high- versus average-risk women (97.7% vs. 0.9%, p < 0.01). Among average-risk women, incongruent screening was more likely among those with dense versus nondense breasts (2.0% vs. 0.1%, p < 0.01). Among high-risk women, incongruent screening was more likely among those with nondense versus dense breasts (99.5% vs. 95.2%, p < 0.01). The significant main effects of density and high-risk on increased incongruent screening were qualified by a density by high-risk interaction, showing a weaker association between risk and incongruent screening among women with dense breasts (simple slope = 3.71, p < 0.01) versus nondense breasts (simple slope = 5.79, p < 0.01). Age and race were not associated with incongruent screening.

conclusionsLack of adherence to evidence-based screening guidelines has led to underutilization of supplementary imaging for high-risk women and potential overutilization for women with dense breasts without other risk factors.