Relationship between body mass index and malignancy rates of MRI-guided breast biopsies: impact of clinicodemographic factors.

PURPOSE

To determine the positive predictive value (PPV) of magnetic resonance imaging (MRI)-guided breast biopsy stratified by body mass index (BMI). Secondary endpoints include evaluation of indications for breast MRI and identification of factors associated with malignant biopsy.

METHODS

We retrospectively analyzed results of MRI-guided breast biopsies in a consecutive cohort of women at a single institution between 2014 and 2019. The PPV was compared between BMI subgroups and the overall group by the one-sample z-test. Factors associated with malignant biopsy were analyzed using multivariate regression analysis.

RESULTS

Among 427 MRI-guided breast biopsies, the PPV was significantly higher in patients with a BMI ≥ 35 compared to BMI < 35 (38.6% versus 24.5%, p = 0.043). This remained true in the 180 biopsies from high-risk screening studies, but there was no difference in PPV by BMI in the 205 biopsies performed to evaluate extent of known disease. Among this cohort who underwent MRI-guided breast biopsy, the underlying indication for MRI was less likely to be high-risk screening in those with a higher BMI or Black or Hispanic race (p = 0.015 and p < 0.001, respectively). For high-risk screening studies, only BMI ≥ 35 was associated with malignant biopsies (OR 37.5, p = 0.003). For evaluation of extent of disease studies, only increased lesion size was a significant predictor of malignant result (OR 1.01, p = 0.04).

CONCLUSIONS

Among women who underwent MRI-guided breast biopsy, elevated BMI was associated with increased PPV and malignant biopsies. Patients with a higher BMI or Black or Hispanic race who had MRI-guided biopsy were less likely to be undergoing high-risk screening and more likely to have breast MRI to evaluate extent of known disease.