Sequential methotrexate and fluorouracil for the treatment of node-negative breast cancer patients with estrogen receptor-negative tumors: eight-year results from National Surgical Adjuvant Breast and Bowel Project (NSABP) B-13 and first report of findings from NSABP B-19 comparing methotrexate and fluorouracil with conventional cyclophosphamide, methotrexate, and fluorouracil.

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PURPOSE: To compare sequential methotrexate (M) and fluorouracil (F) (M-->F) with surgery (National Surgical Adjuvant Breast and Bowel Project [NSABP] B-13) and cyclophosphamide (C), M, and F with M-->F (NSABP B-19), in patients with estrogen receptor (ER)-negative tumors and negative axillary nodes. PATIENTS AND METHODS: A total of 760 patients were randomized to B-13; 1,095 patients with the same eligibility requirements were randomized to B-19. Disease-free survival (DFS), distant disease-free survival (DDFS), and survival were determined using life-table estimates. RESULTS: A significant benefit in overall DFS (74% v 59%; P < .001) was demonstrated at 8 years in all B-13 patients who received M-->F (69% v 56% [P = .006] in those <or= 49 years of age, and 81% v 63% [P = .002] in those >or= 50 years). A survival advantage was evident in older patients (89% v 80%; P = .03). In B-19, through 5 years, an overall DFS advantage (82% v 73%; P < .001) and a borderline survival advantage (88% v 85%; P = .06) were evident with CMF. The DFS (84% v 72%; P < .001) and survival (89% v 84%; P = .04) benefits from CMF were greater in women aged <or= 49 years. M-->F or CMF after lumpectomy and breast irradiation resulted in a low probability of ipsilateral breast tumor recurrence (IBTR). In B-13, the frequency of IBTR was 2.6% following M-->F versus 13.4% in women treated by lumpectomy; it was 0.6% following CMF in B-19. Toxicity >or= grade 3 was more frequent among CMF patients in B-19. The age-related difference in CMF benefit was not related to amount of drug received. CONCLUSION: M-->F and CMF are effective for node-negative patients with ER-negative tumors. The incidence of local-regional or distant metastases and IBTR decreased after either therapy. The benefit from either therapy was evident in all patients, but the CMF advantage was greater in those <or= 49 years. Because it is less toxic, M-->F may be used in patients with medical problems that would preclude CMF administration.