Abstract P1-13-04: Optimal duration of adjuvant chemotherapy for high risk node negative breast cancer patients: 6-year results of the prospective randomized phase III trial PACS 05.

Abstract

Abstract BACKGROUND: In 2000, the NIH Consensus meeting concluded that 4 to 6 cycles of adjuvant chemotherapy appeared to provide an optimal benefit; So, we underwent a prospective randomized trial comparing 4 and 6 cycles of FEC 100 (JCO 2005; 23: 2686–2693) for high risk node negative breast cancer patients. METHODS: This study enrolled 18–65 y women with operable breast cancer, without axillary lymph node involvement, or presence of isolated tumor cells, with size superior to 1 cm and another poor prognostic factor: T > 2 cm, HR –, SBR grade II or III, age < 35 y. After adequate breast surgery and axillary lymph node dissection or sentinel node technique, they were randomized between arm A, 6 cycles of FEC 100, and arm B, 4 cycles, every three weeks. The local regional treatment was completed following usual recommendations. All HR+ patients received hormonal therapy for 5 years. After August 2005, patients with HER2+ tumors were excluded from this study. The primary end point was PFS at 5 years. This study was powered to detect a 6% difference in favour of 6 cycles. Between August 2002 and September 2006, 1516 patients were randomized; 1515 are analysed in ITT. Three patients in the B group did not receive any chemotherapy. There is no significant difference between the two arms for tumor and patient characteristics. RESULTS At a median follow-up of 73 months we observed regarding PFS a low event rate, 197 for the entire population (13%) 91 in arm A median PFS, vs. 106 in arm B median PFS, without any difference between the two groups for DFS, DDFS, local relapse, overall survival. There was no unexpected toxicity. In the arm A we observed more grade III and IV neutropenia, without congestive heart failure. CONCLUSION At a follow-up of 73 months, we observed a low relapse rate, with no significant difference between the two arms. Duration of FEC100 does not induce different outcomes in this population. Question of length of adjuvant treatment is still open with and without taxanes. Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P1-13-04.