Drug treatment of breast cancer.

Breast cancer is the most common malignancy of women in the United States, affecting one out of every 13 women at some time in their lives. Although only 10% of patients have demonstrable distant metastases at the time of diagnosis, a majority will eventually die of disseminated disease. Chemotherapy was formerly considered to be the treatment of last resort in patients with breast cancer, reserved for those who had failed surgery, radiotherapy and hormonal manipulation. However, combination chemotherapy has now been shown to be highly effective. The most active drug combinations produce objective tumour regression in about 60% of patients with advanced disease. Parallel to the development of effective chemotherapy, there has been a renewal of interest in hormonal therapy. The ability to predict whether or not a patient will respond to hormonal therapy has been improved significantly by the clinical application of the oestrogen receptor assay. The selection of a specific treatment for the patients with advanced breast cancer must be individualised. It should take into account a number of prognostic variables, including: sites of metastatic involvement; total extent of disease; disease free interval; menopausal status; and the presence or absence of oestrogen receptor in tumour tissue. The final decision regarding treatment should then be based not only on the probability of response, but also on the anticipated degree of toxicity. Current efforts to improve the management of advanced breast cancer include the development of more effective drug regimens and the combination of chemotherapy with hormonal manipulation. For instance, it would appear that in premenopausal patients, the combination of chemotherapy with oophorectomy may yield results that are superior to those achieved with either treatment alone. The most promising development in the management of early breast cancer has been the use of chemotherapy as an adjuvant treatment in patients with operable disease.