Changing Patterns in Clinicopathological Characteristics of Breast Cancer and Prevalence of BRCA Mutations: Analysis in a Rural Area of Southern China.

Objective: Although the burden of breast cancer remains especially high in rural China, data on the clinicopathological characteristics and prevalence of the breast cancer susceptibility gene 1/2 (BRCA1/2) mutations in patients with breast cancer remain limited. We investigated the clinicopathological characteristics, changing patterns, and prevalence of BRCA1/2 mutations in patients with breast cancer.

Methods: The clinicopathological characteristics of 3712 women with pathologically confirmed primary breast cancer treated at Meizhou People's Hospital between January 2005 and December 2018 were evaluated. The prevalence of BRCA1/2 mutations in 340 patients with breast cancer diagnosed between January 2017 and September 2018 was also evaluated.

Results: The median age at diagnosis was 49±10.5 (range, 20-94) years. Positivity for estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) was observed in 59.0%, 52.5%, and 24.9% of patients, respectively. Time trend analysis revealed that an increasing trend was observed for age at diagnosis (p = 0.001), proportion of patients without a reproductive history (p < 0.001), postmenopausal patients (p = 0.001), invasive pathological cancer type (p = 0.008), ER-positive rate (p < 0.001), PR-positive rate (p = 0.008), and HER2-positive rate (p < 0.001). Compared with patients without BRCA1/2 mutations, those with BRCA1/2 mutations were more likely to have a family history of breast or ovarian cancer (p < 0.001) and have triple-negative breast cancer (TNBC) (p < 0.001). Family history of breast or ovarian cancer (odds ratio [OR], 103.58; 95% confidence interval [CI], 20.58-521.45; p < 0.001) and TNBC subtype (OR, 5.97; 95% CI, 1.16-30.90; p = 0.033) were independent predictors for BRCA1/2 mutation.

Conclusions: The clinicopathological characteristics of patients with breast cancer in this rural area have changed during the past decade. BRCA1/2 testing should be performed in patients with breast cancer with a family history of breast or ovarian cancer and TNBC.