Natural history of more than 20 years of node-positive primary breast carcinoma treated with cyclophosphamide, methotrexate, and fluorouracil-based adjuvant chemotherapy: a study by the Cancer and Leukemia Group B. - Weiss RB; Woolf SH; Demakos E; Holland JF; Berry DA; Falkson G; Cirrincione CT; Robbins A; Bothun S; Henderson IC; Norton L (Journal of clinical oncology : official journal of the American Society of Clinical Oncology, 2003)