Tumor-associated inflammation as a potential prognostic tool in BRCA1/2-associated breast cancer

Abstract

The prognosis of BRCA1/2-associated breast cancer partly depends on histologic characteristics. Most of these breast cancers, however, are poorly differentiated. BRCA1-associated cancers are mainly negative for estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2. Consequently, the use of these histologic features for risk stratification in BRCA1/2 breast cancer is limited. We assessed the prognostic value of additional histologic features, including tumor-associated inflammation and tumor-associated stroma in BRCA1/2 breast cancer patients. From the Rotterdam Family Cancer Clinic database, we collected demographics, tumor characteristics, and follow-up data from female BRCA1/2 breast cancer patients. Tumor samples were centrally reviewed including histologic subtype, differentiation grade, tumor-associated inflammation density, amount of tumor-associated stroma, and intratumor necrosis. The impact of these factors on recurrence-free survival (RFS) was evaluated using univariate and multivariate Cox regression, adjusted for established prognostic features and year of diagnosis. We included 138 BRCA1 and 37 BRCA2 breast cancer patients. Median follow-up after diagnosis was 9.7 years. Independent prognostic factors for RFS were tumor size (hazard ratio [HR], 2.47 for >2 versus ≤2 cm; 95% confidence interval [95% CI], 1.10-5.57), tumor-associated inflammation (HR, 0.18 for moderate/marked versus absent/mild; 95% CI, 0.05-0.61), and intratumor necrosis (HR, 2.60 for presence versus absence; 95% CI, 1.12-6.05). Established prognostic factors as nodal status and differentiation grade were not significantly related to RFS. Subgroup analyses of 138 BRCA1 and 118 triple-negative breast cancer cases showed similar results. Tumor-associated inflammation density was the strongest predictor for RFS in this series of BRCA1/2 breast cancer patients. This provides a potential risk stratification tool that can easily be implemented in routine histologic examination.

Keywords: BRCA1/2; Breast cancer; Prognostic features; Tumor-associated inflammation; Tumor-associated stroma.