Small breast cancers: when and how to treat.

Small (T1a, b), lymph node negative breast tumors represent an entity diagnosed with increasing frequency due to the implementation of wide-scale screening programs. Patients bearing such tumors usually exhibit favorable long-term outcomes, with low breast cancer mortality rates at 10years, even in the absence of adjuvant chemotherapy. However, most available data derive from retrospective studies. Additionally, a subset of patients with these tumors experience recurrence of the disease, indicating that early tumor stage itself is not a sufficient prognosticator. It is of paramount importance to refine the prognosis of this population, identifying patients with high risk of recurrence, for whom adjuvant treatment is needed. The underlying biology of the disease provides relevant information, such as grade and status of hormone receptors and HER-2 (human epidermal growth factor receptor 2), with high grade, triple negative and HER-2-positive tumors having worse prognosis. Additionally, multigene signatures may improve further the prognostication of patients with small, node negative breast cancers. Further research for this increasingly frequent group of patients is urgently needed, so that better informed clinical decision making, in particular regarding adjuvant chemotherapy, can occur.