[Adjuvant endocrine treatment of postmenopausal patients with breast cancer with high risk of recurrence. 5. Results from the DBCG (Danish Breast Cancer Cooperative Group) 77C randomized trial].

The role of antiestrogen treatment of postmenopausal breast cancer patients with high risk of recurrent disease is evaluated in a nationwide, prospective trial conducted by the Danish Breast Cancer Cooperative Group (DBCG). After total mastectomy and postoperative radiotherapy (RT), 840 patients were randomized to treatment with tamoxifen (RT + TAM) for one year, and 824 were randomized to no further therapy (RT). The recurrenceree survival (RFS) after ten years of lifeable analysis is 31% in the RT + TAM treated group, and 28% in the RT group (p = 0.01). Survival is 38% and 34% in the two treatment groups, respectively (p = 0.04). The data were further analyzed with respect to prognostic factors such as age, number of positive nodes, tumour size, and degree of anaplasia. Survival is prolonged in nearly all subgroups of patients treated with RT + TAM. However, the prolongation is only significant in patients with four or more positive nodes, with tumours of less than 5 centimeters or with tumours of anaplasia grade II. Estrogen (ER) and progesterone receptor (PgR) concentrations were measured in tumours from 309 and 219 patients, respectively. Only patients with ER and PgR values above 100 fmol/mg cytosol protein seemed to have a prolongation of survival. In conclusion, a modest survival benefit is achieved with one year of adjuvant tamoxifen treatment. Nevertheless, this is the first example of a systemic treatment approach being able to change the fatal course of breast cancer in postmenopausal patients. By means of endocrine therapy, and in the context of a new randomized trial, the DBCG will try to improve the survival in these patients even further.