Patterns of Treatment Failure — Implications for New Treatment Approaches

Abstract

A rational strategy for improving current adjuvant breast cancer treatment should be built on knowledge of the reasons for failure of the treatment currently utilised. Unfortunately, there are remarkably few data reported which identify why an adjuvant systemic treatment has failed. Most studies of adjuvant systemic treatment have found that the probability of relapse is strongly influenced by the extent of the tumour (tumour size, number of axillary lymph nodes containing metastases, etc.) before local treatment, and this has inevitably led to the assumption that treatment failure is due to the outgrowth of a tumour which is refractory to the administered adjuvant treatment. Recent evidence that relapsed tumours commonly respond to retreatment with the ‘failed’ adjuvant treatment (Valagussa et al. 1986; Muss et al. 1987) has led to studies of cell-kinetic modulation during adjuvant treatment (Davidson and Lippman 1987) and to reintroduction programmes. The results of these treatment programmes are not yet available.