Adjuvant Chemotherapy Followed by Goserelin Versus Either Modality Alone for Premenopausal Lymph Node-Negative Breast Cancer: A Randomized Trial

Abstract

Background: Although chemotherapy and ovarian function suppression are both effective adjuvant therapies for patients with early-stage breast cancer, little is known of the efficacy of their sequential combination. In an International Breast Cancer Study Group (IBCSG) randomized clinical trial (Trial VIII) for pre- and perimenopausal women with lymph node–negative breast cancer, we compared sequential chemotherapy followed by the gonadotropin-releasing hormone agonist goserelin with each modality alone. Methods: From March 1990 through October 1999, 1063 patients stratified by estrogen receptor (ER) status and radiotherapy plan were randomly assigned to receive goserelin for 24 months (n = 346), six courses of “classical” CMF (cyclophosphamide, methotrexate, 5-fluorouracil) chemotherapy (n = 360), or six courses of classical CMF followed by 18 months of goserelin (CMF → goserelin; n = 357). A fourth arm (no adjuvant treatment) with 46 patients was discontinued in 1992. Tumors were classified as ER-negative (30%), ER-positive (68%), or ER status unknown (3%). Twenty percent of patients were aged 39 years or younger. The median follow-up was 7 years. The primary outcome was disease-free survival (DFS). Results: Patients with ER-negative tumors achieved better disease-free survival if they received CMF (5-year DFS for CMF = 84%, 95% confidence interval [CI] = 77% to 91%; 5-year DFS for CMF → goserelin = 88%, 95% CI = 82% to 94%) than if they received goserelin alone (5-year DFS = 73%, 95% CI = 64% to 81%). By contrast, for patients with ER-positive disease, chemotherapy alone and goserelin alone provided similar outcomes (5-year DFS for both treatment groups = 81%, 95% CI = 76% to 87%), whereas sequential therapy (5-year DFS = 86%, 95% CI = 82% to 91%) provided a statistically nonsignificant improvement compared with either modality alone, primarily because of the results among younger women. Conclusions: Premenopausal women with ER-negative (i.e., endocrine nonresponsive), lymph node–negative breast cancer should receive adjuvant chemotherapy. For patients with ER-positive (i.e., endocrine responsive) disease, the combination of chemotherapy with ovarian function suppression or other endocrine agents, and the use of endocrine therapy alone should be studied.