Association of adverse events and survival in colorectal cancer patients treated with adjuvant 5-fluorouracil and leucovorin: Is efficacy an impact of toxicity?

Abstract

Background: Adverse events associated with 5-fluorouracil (5FU) based adjuvant therapy in colorectal cancer (CRC) patients may predict survival. We studied whether haematological (leucopenia, neutropenia, thrombocytopenia) or non-haematological (mucositis, diarrhoea, nausea/vomiting, hand-foot syndrome or other toxicity) adverse events were associated with disease-free survival (DFS) or overall survival (OS) in a large patient material treated with 5-fluorouracil based adjuvant chemotherapy.

Patients and methods: Data from two prospective randomised adjuvant trials were combined to achieve a dataset of 1033 radically operated stage II and III CRC patients treated with either monthly 5FU and leucovorin (LV) as bolus injections (Mayo or modified Mayo) or bi-monthly with bolus and continuous infusion (LV5FU2 or simplified LV5FU2). Toxicities were recorded at each treatment cycle according to NCI-C CTC (the Common Toxicity Criteria of the National Cancer Institute of Canada). The worst toxicity grade was taken into account. The median follow-up time of patients was 6.05 years.

Results: 47% of patients developed neutropenia, 54% nausea/vomiting and 43% mucositis. Any grade neutropenia was associated with improved DFS (hazard ratio (HR) 0.81), any grade nausea/vomiting with improved DFS (HR 0.79) and OS (HR 0.62) and mucositis with improved DFS (HR 0.74) and OS (HR 0.72). Patients experiencing no predefined toxicity had the worst outcome.

Conclusion: Specific adverse events related to adjuvant fluorouracil chemotherapy are associated with improved DFS and OS in early stage CRC patients.

Keywords: 5-Fluorouracil; Adjuvant therapy; Adverse events; Colorectal cancer; Prognosis.