The majority of breast cancer patients are postmenopausal women who are increasingly being offered adjuvant chemotherapy. Since the beneﬁcial effect of chemotherapy in postmenopausal patients predominantly occurs in the ﬁrst 5 years after diagnosis, a prognostic marker for early events can be of use for adjuvant treatment decision making. The aim of this study was to evaluate the prognostic value of the 70-gene prognosis signature for early events in postmenopausal patients.
Frozen tumor samples from 148 patients aged 55–70 years were selected (T1–2, N0) and classiﬁed by the 70- gene prognosis signature (MammaPrintä) into good or poor prognosis. Eighteen percent received hormonal therapy.
Results: Breast cancer-speciﬁc survival (BCSS) at 5 years was 99% for the good-prognosis signature versus 80% for the poor-prognosis signature group (P = 0.036). The 70-gene prognosis signature was a signiﬁcant and independent predictor of BCCS during the ﬁrst 5 years of follow-up with an adjusted hazard ratio of 14.4 (95% conﬁdence interval 1.7–122.2; P = 0.01) at 5 years.
The 70-gene prognosis signature can accurately select postmenopausal patients at low risk of breast cancer-related death within 5 years of diagnosis and can be of clinical use in selecting postmenopausal women for adjuvant chemotherapy.