Monotherapy options in the management of metastatic breast cancer

Anthracyclines and taxanes are the most active agents in the first-line treatment of metastatic breast cancer. Among the options following clinical resistance to anthracycline and/or taxane treatment, the most widely used cytotoxic agents are the vinca alkaloid vinorelbine, the fluoropyrimidine capecitabine, and the nucleoside analogue gemcitabine. No direct comparisons of these agents have been reported in single-agent treatment or in single-agent versus combination treatment. Review of data from phase II trials in metastatic breast cancer indicates that the agents produce comparable response rates and are well tolerated. Review of the relatively smaller amount of data on effects in exclusively anthracycline- or anthracycline-taxane-refractory patient groups yields a similar conclusion. Given the absence of definitive comparisons of these agents, and any marked survival difference on informal comparison, treatment decisions should be aimed at maximizing patient benefit by considering the overall benefit of treatment in relation to the potential harm. A similar approach should be applied when considering use of combinations of these agents versus single-agent treatment.