EFFECT OF SYSTEMIC ADJUVANT TREATMENT ON FIRST SITES OF BREAST-CANCERRELAPSE

Adjuvant systemic treatment for resectable breast cancer changes the n atural history of the disease but provides only a small and delayed ef fect on survival. Evaluation of the types of first relapse avoided by available treatments may explain why effects on mortality are small an d appear late during follow-up. In randomised clinical trials done by the International Breast Cancer Study Group (IBCSG) between 1978 and 1 985, 2108 patients with node-positive disease received more-effective treatments (6 or more cycles of cyclophosphamide, methotrexate, fluoro uracil and prednisone; with or without tamoxifen, or tamoxifen and pre dnisone alone), and 722 patients received less-effective treatments (n o treatment or a single cycle of chemotherapy). 3 main categories of f irst site of relapse were defined and evaluated by cumulative incidenc e analysis: local or regional, and distant soft tissue,bone, and visce ra. The more-effective treatments reduced the cumulative incidence of first relapse in local or regional and distant soft tissue sites at 10 years from 36% to 18% (p=00001); first relapse in bone and viscera wa s not altered by the more-effective treatments. These results were sim ilar for premenopausal and postmenopausal women, and for patients with oestrogen-receptor-positive or oestrogen-receptor-negative tumours. A djuvant systemic treatments in current use improve patient outcome mai nly by reducing the incidence of first local or regional and distant s oft-tissue relapses, while first recurrences in bone or viscera are in fluenced much less. More intensive treatments at present being tested in clinical trials might affect bone and visceral relapses and have a greater and earlier influence on survival.