Understanding quality of life in patients with colorectal cancer: comparison of data from a randomised controlled trial, a population based cohort study and the norm reference population

Quality of life (QoL) is an important outcome measure in clinical studies. However, there is little experience with the interpretation of QoL results.To guide interpretation of QoL results from a randomised controlled trial (RCT) targeting the effectiveness of the immune modulator G-CSF on postoperative recovery in high risk (ASA III/IV) colorectal cancer patients, we compared RCT data with data from a population based cohort study and norm reference data. QoL was assessed using the European Organisation for the Research and Treatment of Cancer (EORTC) QLQ-C30 and CR38 questionnaires. QoL results were analysed on discharge from hospital and six months postoperatively.Colorectal cancer patients (both from the RCT and the cohort study) showed the greatest differences in QoL scores compared to norm reference data at discharge from hospital. Six months postoperatively, global quality of life and pain approximated norm reference values indicating optimal recovery. However, deficits still appeared in scores for role functioning, physical functioning, social functioning and fatigue. The best improvements (discharge from hospital to six months postoperatively) were seen with respect to physical functioning, fatigue and pain.For further analysis of RCT data, physical functioning and fatigue scores may be more sensitive than global quality of life to detect differences in treatment effects.