Heterogeneity of breast cancer I stage: clinical and prognostic value of the carcinoma size T1A, T1B and T1C
During last 25 years there has been a progressive increase in the share of «small» tumors (T1a and T1b) in breast cancer stage I. Biological characteristics of tumor size T1a, T1b and T1c are different. Tumors less then 5mm have favorable biology: a high rate of luminal A subtype of breast cancer that affects the minimum proportion of relapses of the breast cancer and high rates of long-term survival. Biological characteristics of tumor with T1b and T1c size are more aggressive and presented by a high frequency of ductal carcinoma with luminal B and triple-negative immunophenotype, which significantly decreases the prognosis of the disease. Biology «small» tumors should be considered for choosing the optimal adjuvant treatment algorithm for breast cancer stage I.