Prevention of breast cancer recurrence with adjuvant cytotoxic or endocrine therapy.

The paper provides a brief summary of the scientific hypotheses underlying adjuvant trials of systemic treatment in primary breast cancer, the history of the first and second generation of adjuvant studies of cytotoxic and endocrine therapy, and a brief description of the main findings of the international overview of all available randomized trials of adjuvant systemic treatment. In short, the overview has provided conclusive evidence that both adjuvant endocrine therapy (ovarian ablation and tamoxifen) as well as cytotoxic polychemotherapy can prevent disease recurrence and prolong overall survival. However, the treatment benefit appears to be only moderate and may not be considered clinically worthwhile in some patient subsets, e.g. those with a relatively favourable outcome with local treatment alone. Refinements in the use of prognostic factors to select patients for treatment--particularly in node-negative disease--are thus warranted, as well as further research aimed at improving treatment efficacy.