Adjuvant Chemotherapy After Potentially Curative Resection of Metastases From Colorectal Cancer: A Pooled Analysis of Two Randomized Trials

Abstract

Adjuvant systemic chemotherapy administered after surgical resection of colorectal cancer metastases may reduce the risk of recurrence and improve survival, but its benefit has never been demonstrated. Two phase III trials (Fédération Francophone de Cancérologie Digestive [FFCD] Trial 9002 and the European Organisation for Research and Treatment of Cancer/National Cancer Institute of Canada Clinical Trials Group/Gruppo Italiano di Valutazione Interventi in Oncologia [ENG] trial) used a similar design and showed a trend favoring adjuvant chemotherapy, but both had to close prematurely because of slow accrual, thus lacking the statistical power to demonstrate the predefined difference in survival. We report here a pooled analysis based on individual data from these two trials. After complete resection of colorectal liver or lung metastases, patients were randomly assigned to chemotherapy (CT arm; fluorouracil [FU] 400 mg/m(2) administered intravenously [IV] once daily plus dl-leucovorin 200 mg/m(2) [FFCD] x 5 days or FU 370 mg/m(2) plus l-leucovorin 100 mg/m(2) IV x 5 days [ENG] for six cycles at 28-day intervals) or to surgery alone (S arm). A total of 278 patients (CT, n = 138; S, n = 140) were included in the pooled analysis. Median progression-free survival was 27.9 months in the CT arm as compared with 18.8 months in the S arm (hazard ratio = 1.32; 95% CI, 1.00 to 1.76; P = .058). Median overall survival was 62.2 months in the CT arm compared with 47.3 months in the S arm (hazard ratio = 1.32; 95% CI, 0.95 to 1.82; P = .095). Adjuvant chemotherapy was independently associated with both progression-free survival and overall survival in multivariable analysis. This pooled analysis shows a marginal statistical significance in favor of adjuvant chemotherapy with an FU bolus-based regimen after complete resection of colorectal cancer metastases.