Rationale for combining chemotherapy and hormonal therapy in breast cancer

Both chemotherapeutic agents and hormones are effective in breast cancer treatment. Their mechanism of action seems to be conflicting: while cytotoxic drugs are active on cycling cells, hormones prolong the G0 phase. Therefore, the concurrent use of hormones and chemotherapy could decrease their expected clinical activity. On the contrary, a review of the literature suggests that there could be some synergistic action with combined therapy. The problem is therefore to assess the efficacy of simultaneous vs sequential administration of hormones and chemotherapy. In advanced disease the general conclusion could be that simultaneous administration of combined therapy: increases, although the difference is not statistically significant, the response rate both in pre and postmenopausal patients; and the most important end point, total survival, is not statistically improved by simultaneous vs sequential administration. In addition, in the adjuvant setting combined treatment appears superior to chemotherapy only in postmenopausal, receptor-positive patients. No definite conclusion is today available in premenopause.