Effects of Dietary and Physical Activity Interventions on Health-Related Quality of Life Outcomes in Colorectal Cancer Survivors

Introduction Colorectal cancer is the second most common cancer and cancer-killer in Hong Kong. The latest World Cancer Research Fund revealed that foods low in fibre and high in red and processed meat cause colorectal cancer, while physical activity (PA) protects against colon cancer. A trial was conducted to demonstrate the feasibility of two behavioural interventions intended to improve colorectal cancer survivors’ PA level and diet. This study reported the health-related quality of life (HRQoL) outcomes at 6 and 12 months. Methods This was a multi-centre randomised controlled trial with a 2×2 factorial design, in which colorectal cancer patients within their first year of completion of main cancer treatment were randomly allocated to one of the 4 groups: (A) both dietary and PA interventions, (B) dietary intervention only, (C) PA intervention only, and (D) neither intervention but usual care. Subjects under dietary intervention were encouraged to consume less red and processed meat and refined grains, while those under PA intervention were motivated to progressively increase PA. HRQoL outcomes were measured by SF-12 and FACT-Colorectal. Comparisons at 6 and 12 months among the groups were conducted using generalised estimating equations with adjusting baseline values. Results Two hundred and twenty three consented colorectal cancer survivors were randomised. Their mean (standard deviation) age was 65.1 (10.1) years, of which 82 (36.8%) were female. No significant baseline differences among the 4 groups were found. Interaction between the two interventions was insignificant in all HRQoL measures at both time points. At 6-month, PA (A+C versus B+D) significantly improved SF-12 PCS (difference = 3.11, 95% confidence interval = [1.55, 4.68]; p-value < 0.001) and SF12-derived SF-6D Index (0.046, [0.010, 0.082]; p-value = 0.012), but did not significantly change SF-12 MCS and FACT-Colorectal Total Score. The dietary intervention (A+B versus C+D) had no significant effects on all HRQoL measures. At 12-month, the PA effects that were significant at 6-month became insignificant (PCS: 0.40, [–1.24, 2.04]; p-value = 0.631; SF-6D Index: –0.011, [–0.050, 0.027]; p-value = 0.569), but the diet intervention significantly increased SF-6D Index (0.042 [0.004, 0.080]; p-value = 0.029). The effects on all other HRQoL measures remained insignificant. Conclusions The results revealed that increased PA may help improving colorectal cancer survivors’ physical health at 6 months but no effect was found at 12 months