Efficacy of adjuvant fluorouracil and folinic acid in B2 colon cancer. International Multicentre Pooled Analysis of B2 Colon Cancer Trials (IMPACT B2) Investigators

Abstract

Purpose: The goal of this analysis was to determine whether fluorouracil (FU) and folinic acid (leucovorin, LV) is an effective adjuvant therapy for patients after potentially curative resection of colon cancer in patients with B2 tumors.

Patients and methods: One thousand sixteen patients with B2 colon cancer entered onto five separate trials were randomized to FU + LV or observation. A pooled analysis for event-free (EFS) and overall survival (OS) using a stratified log-rank and Cox model was performed.

Results: The median follow-up duration was 5.75 years. Patients receiving FU + LV did not experience a significant increase in EFS or OS. The hazards ratio at 5 years was 0.83 (90% confidence interval, 0.72 to 1.07) for EFS and 0.86 (90% confidence interval, 0.68 to 1.07) for OS. The 5-year EFS was 73% for controls and 76% for FU + LV. The 5-year OS was 80% for controls and 82% for FU + LV. Increasing age and poorly differentiated tumors were significant indicators of poor prognosis (P < .02).

Conclusion: This data set does not support the routine use of FU + LV in all patients with B2 colon cancer. Longer follow-up may identify a small benefit. At present, studies in B2 colon cancer designed with a no-treatment control arm should be considered appropriate.