The combination of Ki67, histological grade and estrogen receptor status identifies a low-risk group among 1,854 chemo-naive women with N0/N1 primary breast cancer

We have confirmed a prognostic index based on a proliferation marker (Ki67), histological grade, and ER for identification of a low-risk group of patients with N0/N1 primary breast cancer. For this low-risk group constituting 57% of the patients, with a five-year distant disease-free survival of 92%, adjuvant chemotherapy will have limited effect and may be avoided.