Clinical and biological characteristics of T3N0M0 and T4N0M0 breast cancer

T3-4N0M0 breast cancer is rather rare among all breast cancers. The clinical features of these tumors and their biological nature are poorly studied in the scientific literature. In this study we showed that patients with T3N0M0 and T4N0M0 tumors revealed a number of common clinical features, comorbidities and biological characteristics of the tumor. At the same time carcinomas differed in their aggressiveness and the course of the disease. The history was shorter and the average tumor size was larger among patients from T3N0M0 group than in the T4N0M0 group, which indicates a higher tumor growth rate. Also, mean proliferation index ki-67 was higher in the T3N0M0 group than in the T4N0M0 group. The proportion of triple-negative and luminal B Her2-negative biological subtypes was the largest in both the T3N0M0 and T4N0M0 groups. More than 50 % of women with T3-4N0M0 tumors had carcinomas with zero or low expression of hormonal receptors. Thus, such tumors were more aggressive and potentially highly sensitive to systemic chemotherapy in a significant proportion of patients with T3-4N0M0 breast cancer in our study.