Pathologic Features and Biomarker Expression among Young Women with Breast Cancer: Results from the Young Women's Breast Cancer Study.

Abstract

Abstract Background: Prior studies have suggested a higher prevalence of high grade, ER-negative and HER2-positive tumors as well as basal-like carcinomas in young women with breast cancer; features that are associated with a more aggressive phenotype and decreased survival. However, studies are limited by small numbers among the very young (<35 years). Thus the distribution of poor prognostic features of breast cancers arising in young women remains unclear. We examined the clinical and pathologic features and biomarker expression patterns in relation to patient age in a large group of young women with invasive breast cancer.Design: The Young Women's Breast Cancer Study is an ongoing multi-center prospective cohort enrolling women with newly diagnosed breast cancer at age ≤ 40 years old. Medical records are reviewed for clinical characteristics, tumor stage and receptor status. HER2 positivity is defined as IHC 3+ or FISH amplified. Pathologic features are examined by central review, with detailed evaluation of phenotypic features associated with basal-like carcinomas. Univariate logistic regression models were used to evaluate the relationship to age, as a continuous variable and each clinico-pathologic feature.Results:The first 248 women for whom pathology has been reviewed (71% of participants enrolled to date) are included in this analysis. The table below presents the distribution of pathologic features by age group. There are no statistically significant differences in ER expression, PR expression or HER2 overexpression by age at diagnosis. Nor are the youngest women more likely to have higher stage or higher grade tumors. However, the youngest women are more likely to have pushing tumor margins and zones of tumor necrosis (p=0.03 and p=0.01 respectively).Clinico-pathologic Feature<30 years (n=27) (%)31-35 years (n=70) (%)36-40 years (n=151) (%)ER positive17 (63)47 (67)96 (64)PR positive15 (56)44 (63)90 (60)HER2 positive7 (26)26 (37)40 (27)Grade 316 (59)44 (63)80 (53)Poor stage5 (19)14 (20)27 (18)Ductal type22 (81)58 (83)132 (87)Fibrotic focus present12 (44)18 (26)51 (34)Tumor necrosis present14 (52)13 (19)38 (25)Prominent lymphocytic infiltrate8 (30)13 (19)36 (24)Pushing tumor margins11 (41)21 (30)36 (24) Conclusion:We find no differences in the distribution of poor prognostic features such as higher tumor stage, high tumor grade, ER/PR negativity or HER2 positivity among the very young. However, our study does indicate that the youngest women are significantly more likely to have tumors with pushing margins and zones of tumor necrosis, which are some of the morphologic features associated with the basal-like phenotype. Further research is warranted to evaluate the implication of these findings with regard to the etiology, treatment and prognosis of breast cancer in young women. Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 6007.