Simultaneous or sequential chemotherapy for locally advanced breast cancer.

Chemotherapy of breast cancer is still an area of intensive research. Based on mathematical model of tumor cell growth kinetics, a novel concept of chemotherapy in breast cancer was launched which implies dose-densification of chemotherapy through the use of sequential non crossresistant single agents or regimens. The relative infrequency of locally advanced breast cancer (LABC) has limited the speed of clinical progress in this area. The introduction of primary (neoadjuvant) systemic chemotherapy (PSCT), however, improved the outcome of patients with LABC. The first data concerning neoadjuvant sequential chemotherapy were related to primary operable breast cancer. Many studies, using the two most active classes of cytotoxic drugs, anthracyclines and taxanes, in primary breast cancer, showed that sequential PSCT was superior to simultaneous combination chemotherapy in terms of enhancing the rates of patients rendering suitable for breast-conserving (BC) treatment. There are few trials dealing with sequential PSCT in LABC. In the majority of them sequential dose-dense PSCT was administered because the rapid delivery of the most active cytotoxic drugs (anthracyclines and taxanes) is necessary to achieve reduction of the size of the primary tumor, to increase the possibility of BC treatment and to eliminate occult distant micrometastases, contributing thus to possible prolongation of survival. This article summarises recent data concerning sequential PSCT in LABC in order to evaluate its possible use in clinical practice.