Abstract S3-02: NSABP B-36: A randomized phase III trial comparing six cycles of 5-fluorouracil (5-FU), epirubicin, and cyclophosphamide (FEC) to four cycles of adriamycin and cyclophosphamide (AC) in patients (pts) with node-negative breast cancer

Abstract

Abstract Background NSABP B-36 was originally designed as a 2X2 factorial randomized study to compare 6 cycles of FEC-100 with 4 cycles of standard AC with or without celecoxib in pts with node-negative breast cancer. The rationale for the trial was based on observations from other adjuvant trials suggesting that longer duration of anthracycline-based therapy may result in improved outcomes and also on accumulating evidence that prostaglandins may contribute to the malignant phenotype in breast cancer. The trial opened in May 2004 but random assignment to celecoxib v placebo was terminated in December 2004 (after 327 pts were enrolled) because of concerns for increased risk of cardiovascular disease with the use of COX-2 inhibitors. The trial continued as a two-arm study and completed accrual in July 2008. The primary endpoint of disease-free survival (DFS), and secondary endpoints of overall survival (OS), recurrence-free interval (RFI), distant recurrence-free interval (DRFI), and adverse events comparing FEC-100 and AC are reported here. Analyses of quality of life indicators will be reported separately. Methods 2,722 pts with T1-3, pN0 breast cancer were randomly assigned to either adriamycin 60 mg/m2 and cyclophosphamide 600mg/m2 every 21 days for 4 cycles (n=1361) or 5-FU 500mg/m2, epirubicin 100 mg/m2 and cyclophosphamide 500 mg/m2 every 21 days for 6 cycles (n=1361). Hormone- receptor positive pts were to receive physician's choice of hormonal therapy for a minimum of 5 yrs. Trastuzumab for HER2-positive pts was at investigator's discretion but was not to begin for >3 weeks after the last dose of chemotherapy. All women treated with lumpectomy were to receive breast radiotherapy; post-mastectomy chest wall radiotherapy was at physician's discretion. The differences in DFS (OS, RFI, and DRFI) between two treatment arms were assessed by log-rank test stratified by hormone receptor status and type of surgery. Results Median follow-up is 82.8 months. Pt and tumor characteristics were equally distributed between the two groups (<50 years old: 40%, lumpectomy: 68%, and hormone positivity: 65 %). Overall, Grade 3 and 4 expected toxicities were more frequent in the FEC arm. Combined Grade 3/4 toxicities reaching statistical significance with a difference of 3% or more between AC and FEC arms included fatigue 3.55% v 8.45%, febrile neutropenia 3.70% v 9.42%, and thrombocytopenia 0.74% v 4.41%, respectively. While on treatment, Grade 3 left ventricular systolic dysfunction occurred in one pt in each arm. There were 2 toxicity deaths on AC and 5 on the FEC arm. Primary and secondary endpoint analyses at 8 ys did not reveal any significant differences in DFS, OS, RFI, or DRFI. EndpointAC (%)FEC (%)HRCIp-valueDFS83.082.81.040.85,1.260.70OS91.292.00.940.71,1.240.65RFI90.090.40.970.76,1.260.84DRFI92.393.00.890.66,1.200.43 Conclusions Six cycles of the FEC-100 regimen did not result in any efficacy advantage over 4 cycles of standard AC in node-negative breast cancer pts. As anticipated, the FEC-100 regimen resulted in greater toxicity. Support NCI: U10-CA-12027, -37377, -69974, -69651, -44066-26; Pharmacia & Upjohn Co. Citation Format: Jacobs A Samuel, John W Wilson, Hanna Bandos, Richard M Elledge, André Robidoux, Louis Fehrenbacher, Patrick J Ward, Johnathan Polikoff, Adam M Brufsky, Louise Provencher, Alexander HG Paterson, John T Hamm, Robert L Carolla, Luis Baez-Diaz, Priya Rastogi, Thomas B Julian, D Lawrence Wickerham, Sandra M Swain, Charles E Geyer Jr, Eleftherios P Mamounas, Norman Wolmark. NSABP B-36: A randomized phase III trial comparing six cycles of 5-fluorouracil (5-FU), epirubicin, and cyclophosphamide (FEC) to four cycles of adriamycin and cyclophosphamide (AC) in patients (pts) with node-negative breast cancer [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr S3-02.