Controversies of chemotherapy for the treatment of metastatic breast cancer.

Metastatic breast cancer (MBC) remains an incurable disease. The aims of treatment include tumour shrinkage, symptom control, delay of disease progression and prolongation of survival while maintaining an acceptable quality of life. In the last decade, a decline in mortality has been observed. Combination chemotherapy generally provides some survival advantage over single-agent chemotherapy. Taxanes and antimetabolites are among the most effective agents, providing a balance between efficacy and tolerability. Increasing numbers of patients are receiving adjuvant anthracycline and taxane therapy. In these patients, treatment options include cytotoxic agents not used in adjuvant treatment, re-challenge with anthracycline and taxanes, or new targeted agents such as pertuzumab, lapatinib or bevacizumab. Biology of the disease at cell level plays a major role in treatment choice. Key points in the intracellular signal transduction pathways relevant for cell proliferation, apoptosis and the angiogenesis/metastasis process, represent possible targets for new target-specific agents. Tailored therapies are a step forward in improving patients' prognosis.