Abstract P1-13-09: Long-term follow-up of two randomized controlled trials (N-SAS-BC01 trial and CUBC trial) comparing oral tegafur-uracil (UFT) versus classical cyclophosphamide, methotrexate, and 5-fluorouracil (CMF) as adjuvant therapy in early breast cancer

Abstract

Abstract Background: Two randomized controlled trials comparing the efficacy of oral tegafur-uracil (UFT) (2 years) with that of classical cyclophosphamide, methotrexate, and 5-fluorouracil (CMF) (6 courses) were conducted in patients with resected early breast cancer. UFT is an oral fluoropyrimidine that combines tegafur, a prodrug of 5-fluorouracil, with uracil in a 1:4 molar ratio. One study was the N-SAS-BC01 trial (Watanabe et al, J Clin Oncol 2009), which was conducted in patients with high-risk node-negative breast cancer (n=733). The other was the CUBC trial (Park et al, Br J Cancer 2009), which was performed in patients with node-positive breast cancer (n=377). We reported the pooled analysis of these two randomized control trials using individual patient data (Ohashi et al, Breast Cancer Res Treat 2010). This pooled analysis showed that UFT was non-inferior to CMF in terms of inhibiting recurrence of estrogen receptor (ER)-positive early breast cancer. In addition, an exploratory subgroup analysis showed that UFT may be more effective in ER-positive patients who were 50 years or older. The present study was conducted to investigate the long-term efficacy of UFT or CMF in patients with early breast cancer. Methods: Long-term follow-up data for disease recurrence and survival were collected. Hazard ratios (HR) were determined using the Cox model stratified by study and adjusted for clinical characteristics, namely age, tumor size, nodal status, histological type, ER, and progesterone receptor (PgR). Survival curves were estimated by the Kaplan-Meier method. Hochberg multiplicity adjustment was applied in the previous pooled analysis, and non-inferiority of UFT versus CMF was shown in terms of relapse-free survival (RFS) in the ER-positive patient group. We investigated the non-inferiority of UFT in the same patient group with updated data. Restricted mean survival time (RMST) was calculated to consider the relative efficacy of UFT. This study is registered with JapicCTI-163321. Results: In total, 1,057 patients were analyzed (CMF, n=528; UFT n=529). The median follow-up time was 11.1 years (12.1 years in the N-SAS-BC 01 trial and 8.3 years in the CUBC trial). Table 1 shows the 10-year RFS and overall survival (OS) in all patients and ER-positive patients. The difference in RMST between arms at 20 years in terms of RFS was -2.7 months in all patients and 3.4 months in ER-positive patients. Table 2 shows the HR for RFS according to ER status and age. UFT (%)CMF (%)UFT to CMF; HR (95% CI)10-year RFSall patients74.477.11.02 (0.81–1.30)ER-positive patients75.075.10.91 (0.66–1.27)10-year OSall patients86.886.90.98 (0.72–1.34)ER-positive patients89.987.90.86 (0.54–1.37) Age <50 yearsAge ≥50 yearsER negative1.76 (0.95–3.26)0.93 (0.58–1.51)ER positive1.29 (0.74–2.23)0.76 (0.50–1.16) Conclusion: This study shows that UFT was shown to be non-inferior to CMF in terms of RFS in ER-positive early breast cancer. This result is similar to that of the previous pooled analysis. Sponsor: Taiho Pharmaceutical Co., LTD Citation Format: Yonemori K, Ohsumi S, Takao S, Tokuda Y, Ito Y, Nakagami K, Takahashi M, Yoshidome K, Nakayama T, Yamaguchi Y, Ohashi Y, Inaji H, Watanabe T. Long-term follow-up of two randomized controlled trials (N-SAS-BC01 trial and CUBC trial) comparing oral tegafur-uracil (UFT) versus classical cyclophosphamide, methotrexate, and 5-fluorouracil (CMF) as adjuvant therapy in early breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P1-13-09.