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

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-fable 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 less than or equal to 49 years of age, and 81% v 63% [P = .002] in those greater than or equal to 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 less than or equal to 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 greater than or equal to 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 less than or equal to 49 years, Because it is less toxic, M-->F may be used in patients with medical problems that would preclude CMF administration.