Association Between Radio-pathological Breast Tumor Characteristics and Mammographic Breast Density

Background: Despite mammographic density being a strong indicator of breast cancer risk, it is unclear whether there is association between breast density and certain breast cancer subtypes. This study aimed to investigate the relation between radiologic breast density category and tumor characteristics. Methods: Patients with histologically proven breast cancer who had undergone diagnostic mammography were reviewed retrospectively from 2016 to 2019. The American College of Radiology BI-RADS mammographic density categories were recorded and grouped into low (a and b), and high (c and d). Patient characteristics as well as tumor size, border, pathology, ER, PR, Her2 immunohistochemistry was extracted from the mammography, ultrasonography, and core needle pathology reports. Binary logistic regression model was used to analyze the association between breast density and receptors, molecular subtypes, or tumor features. Results: The present study was comprised of 129 patients, with 7, 47, 41, and 34 patients in the density categories a, b, c, and d, respectively. Patients who had a higher breast density were significantly younger (p=0.001). Those with a lower density were more likely to have HER2, IHC 0 tumors (Odds ratio adjusted for age = 4.9, 95% CI 1.25-18.27, p=0.022). Mammographic density was not related to molecular subtypes and other tumor features. Conclusion: Mammographic dense breast may be associated with Her2 positive breast cancer.