Association of mammographic density with hormone receptors in invasive breast cancers — results from a case-only study
Menée en Allemagne, cette étude de cas incluant 2 410 patientes atteintes d'un cancer du sein évalue l'association entre la densité mammaire et l'expression des récepteurs hormonaux
Introduction For many breast cancer (BC) risk factors, there is growing evidence concerning molecular subtypes for which the risk factor is specific. With regard to mammographic density (MD), there are inconsistent data concerning its association with estrogen receptor (ER) and progesterone receptor (PR) expression. The aim of this study was to analyze the association between ER and PR expression and MD. Methods In this case-only study, data on BC risk factors, hormone receptor expression, and MD were available for 2410 patients with incident BC. MD was assessed as percent mammographic density (PMD) using a semiautomated method by two readers for every patient. The association of ER/PR and PMD was studied with multifactorial analyses of covariance (ANCOVA) with PMD as the target variable and including well-known factors that are also associated with MD, such as age, parity, use of hormone replacement therapy, and body mass index (BMI). Results In addition to the commonly known associations between PMD and age, parity, BMI, and hormone replacement therapy, a significant inverse association was found between PMD and ER expression levels. Patients with ER-negative tumors had an average PMD of 38%, whereas patients with high ER expression had a PMD of 35%. A statistical trend towards a positive association between PMD and PR expression was also seen. Conclusion PMD appears to be inversely associated with ER expression and may correlate positively with PR expression. These effects were independent of other risk factors such as age, BMI, parity, and hormone replacement therapy, possibly suggesting other pathways that mediate this effect. © 2012 Wiley-Liss, Inc.