Respective roles of radiotherapy and chemotherapy in adjuvant treatment of cancer of the breast: theoretical importance and feasibility of chemoradiotherapy

Concomitant radiochemotherapy is of potential interest in the treatment of early stage breast cancer. Radiotherapy improves local control after both conservative surgery and mastectomy and in this last case also improves overall survival. Some questions however still exist concerning the role of the delay between surgery and radiotherapy on the efficacy of this treatment. Over 6 months, the benefit due to radiotherapy could be reduced. Adjuvant chemotherapy leads to improved survival in all categories of patients with breast cancer, either with or without axillary-node involvement. Anthracyclin-containing regimens seem to be the most efficient, but their superiority on "historical" standard regimens such as cyclophosphamide-methotrexate-5-fluorouracil has never been fully established. Chemotherapy and radiotherapy have synergistic effects. Used simultaneously, their effect on residual disease after surgery could be increased. Moreover, this therapeutic modality enables reduction of treatment duration as well as the delay between surgery and radiotherapy. Some studies have demonstrated the good tolerance of concomitant radiotherapy and FNC (5-fluoro-uracil, mitoxantrone and cyclophosphamide) or CMF. Three French randomized trials testing the value of concomitant vs sequential radiotherapy + chemotherapy are ongoing. However, careful and critical interpretation of survival data will be required to consider concomitant chemoradiotherapy as a standard adjuvant treatment of early stage breast cancer.