ADJUVANT CHEMOENDOCRINE THERAPY FOR EARLY BREAST-CANCER - IS IT WORTHWHILE - (REVIEW)

The overview published in 1999 by the Early Breast Cancer Trialist' Cooperative Group demonstrated that systemic therapy after surgical removal of primary breast tumors prolongs both disease-free and overall survival of patients when compared with no systemic therapy, Specifically, both chemotherapy and ovarian ablation in patients aged less than 50 and tamoxifen in those aged 50 or more achieve a reduction of one-fifth to one-fourth in the annual odds of recurrence or death from any cause. The relative effect of different therapies is independent of the stage of the disease, while the absolute benefit depends not only upon the relative effect of treatment but also upon the baseline prognosis of patients. The overview did not report a direct estimation of the effect of combined chemoendocrine adjuvant therapy. Among the effects that may confound the evaluation of chemoendocrine adjuvant therapy are: (a) the possibility of biological interactions between drugs; (b) the presence on tumor cells of steroid hormone receptors; (c) the suppression of ovarian activity induced by chemotherapy in most premenopausal patients; (d) the scheduling of chemotherapy and endocrine therapy. Based on data of the overview, relevant questions are: (i) does the addition of endocrine therapy (tamoxifen dr ovarian ablation) to chemotherapy improve the outcome of premenopausal patients? (ii) does the addition of chemotherapy to tamoxifen improve the outcome of postmenopausal patients? We have reviewed single randomised trials in an attempt to answer these questions. In premenopausal patients, the addition of tamoxifen to chemotherapy probably induces only small advantages. The addition of ovarian ablation to chemotherapy could improve survival. The relationship between oophorectomy and receptor status has not been extensively studied; however, the addition of oophorectomy, like the addition of tamoxifen, to chemotherapy could be cost effective in cases of estrogen receptor-positive tumors. The effect of tamoxifen in association with ovarian ablation, after chemotherapy, has not yet been studied. In postmenopausal patients the addition of chemotherapy to tamoxifen is debated. The role of receptor status seems to be important in these patients. Most studies found that chemotherapy does not significantly increase the effect of tamoxifen in the subgroup of patients with receptor-positive tumors, while it does increase toxicity. On the contrary, the addition of chemotherapy to tamoxifen, in patients with receptor-negative tumors could significantly improve results.