A phase III adjuvant randomised trial of 6 cycles of 5-fluorouracil-epirubicine-cyclophosphamide (FEC100) versus 4 FEC 100 followed by 4 Taxol (FEC-T) in node positive breast cancer patients (Trial B2000)

Abstract

Background: Standard adjuvant chemotherapy regimens for patients with node positive (N+) breast cancer consisted of anthracycline followed by taxane. The European Association for Research in Oncology embarked in 2000 on a phase III trial comparing 6 cycles of FEC100 versus 4 FEC100 followed by 4 Taxol. Primary end-point was disease free survival. Secondary end-points were overall survival, local recurrence free interval, metastases free interval and safety.

Patients and methods: Between March 2000 and December 2002, 837 patients were randomised between 6FEC100 for 6 cycles (417patients) or FEC100 for 4 cycles then Taxol 175mg/m(2)/3 weeks for 4 cycles (4FEC100-4T) (420 patients). One thousand patients had been planned initially but the trial was closed earlier due to slow accrual.

Results: Hazard ratios (HRs) were 0.99 for disease-free survival (DFS) (95%CI: 0.77-1.26; p=0.91), and 0.85 for overall survival (OS) (95%CI: 0.62-1.15; p=0.29). Nine-year DFS were 62.9% versus 62.5% for 6FEC100 and 4FEC100-4T, respectively. Nine-year OS were 73.9% versus 77% for 6FEC100 and 4FEC100-4T, respectively. Toxicity analyses based on 803 evaluable patients showed that overall grade 3-4 toxicities were similar in both arms (63% versus 58% for 6FEC100 arm and 4FEC100-4T arm, respectively; p=0.16).

Conclusion: In this trial replacing the last 2 FEC100 cycles of 6FEC100 regimen by 4 Taxol does not lead to a discernable DFS or OS advantage. The lack of a significant difference between the randomised treatment arms may however be due to a lack of power of this trial to detect small, yet clinically worthwhile, treatment benefits.

Keywords: Adjuvant chemotherapy; Anthracycline; Breast cancer; Efficacy; Paclitaxel; Phase III.