Anti‐estrogen treatment of postmenopausal breast cancer patients with high risk of recurrence: 72 months of life‐table analysis and steroid hormone receptor status

Abstract

The role of anti‐estrogen treatment of postmenopausal breast cancer patients with high risk of recurrent disease is evaluated in a nationwide, prospective, randomized trial conducted by the Danish Breast Cancer Group. After total mastectomy and postoperative radiotherapy, 829 patients were randomized to treatment with tamoxifen (RT + TAM) for 1 year and 821 were randomized to no further therapy (RT). The recurrence‐free survival (RFS) after 72 months of life‐table analysis is 44% in the RT + TAM treated group, and 40% in the RT group (p=0.0003). Survival is 51% in both treatment groups (p=0.53). The data have been further analyzed with respect to prognostic factors such as age, degree of anaplasia, tumor size, and positive nodes. The RFS is lower in all subsets of patients treated with RT + TAM, but is only significant in patients 50–59 years of age, with tumors of anaplasia grade I, with tumors less than 5 cm, or with 4 or more positive lymph nodes.Estrogen receptor concentrations were measured in a subset of 291 of these patients. A cut‐off limit of 10 fmol/mg cytosol protein and the use of a Cox proportional hazards model distinguished between patients with long RFS and those with early recurrent disease. Patients with an estrogen receptor content below 100 fmol/mg did not benefit from the endocrine therapy, while those with concentrations above 100 fmol/mg had a significantly longer RFS. Progesterone receptor determinations were performed in 12% of the patients. Progesterone receptor‐positive patients had a lower rate of recurrence when treated with RT + TAM compared to the receptor‐positive patients in the RT group (p=0.017).