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Colorectal cancer (CRC) incidence is increasing at an alarming rate in Hong Kong. A recent World Cancer Research Fund (WCRF) report concluded physical activity (PA) protects against colon cancer and foods low in dietary fibre, red meat and processed meat cause CRC. Yet, the influence of lifestyle factors on cancer outcome (i.e. recurrence and survival rates) in CRC survivors is largely unknown. Our literature review showed a paucity of published studies on lifestyle intervention in CRC survivors; none had investigated the effect of such intervention on cancer outcomes. With advances in treatment, CRC survivors live longer. Many of them are motivated to make lifestyle changes. However, our qualitative research has shown a huge service gap in the provision of appropriate PA and dietary advice to CRC survivors. Many patients were unaware of the link between PA and diet with CRC outcome but most demonstrated acceptance of lifestyle intervention. Yet, there is currently no scientifically-based evidence to allow firm recommendations to be made.
Our study aims to evaluate the acceptability of two behavioural interventions for CRC survivors intended to improve cancer outcome and designed to (1) increase PA levels (to 60 minutes of moderate PA 5 days/week) and (2) reduce consumption of a Western diet (<5 servings of red/processed meat weekly and 2 servings of refined grains daily). We hypothesize that the proposed interventions are (1) efficacious in changing the two targeted behaviours; and (2) acceptable to CRC survivors with compliance rates of about 80%.
The study follows the Medical Research Council Framework for the design and evaluation of complex interventions. Phases 0 and 1 (funded by WCRF) have been completed. This application seeks funding for a Phase 2 feasibility trial. Two hundred and twenty-four CRC survivors within 12 months of completion of cancer treatment and without evidence of persistent/recurrent disease will be recruited from four public hospitals in Hong Kong after informed consent. Subjects will be randomized in a 2x2 factorial design for the two targeted behaviours prescribed over 12 months. Primary outcome measure is whether the target levels of PA and dietary intake could be met at the end of intervention. Secondary outcome measures include: (1) magnitude of changes in PA level and dietary intakes; (2) rates and determinants of compliance; (3) facilitators and barriers to behavioural change; (4) measurement of theoretical constructs underlying PA and dietary interventions; (5) possible health benefits (body composition, physical fitness, quality of life and mood) and side effects (PA-associated injury and nutritional deficiency) arising from the interventions. Outcome will be assessed at baseline, 6 months into intervention and then at 0, 6 and 12 months post-intervention.
To the best of our knowledge, this is the first behavioural intervention model targeting PA and reduced consumption of a Western diet in CRC survivors. If proven feasible, our intervention programme would pave way for a large randomized controlled trial testing the effect of PA and diet on the treatment outcome of CRC.
Colorectal or bowel cancer (CRC) is increasing in incidence at a very alarming rate in Hong Kong. A recent authoritative report from the World Cancer Research Fund (WCRF) concluded that physical activity and foods containing dietary fibre protects against bowel cancer whereas red meat and processed meat cause bowel cancer. Yet, we do not know if these lifestyle factors affect the treatment outcome (i.e. survival and relapse rates) in the increasing number of bowel cancer survivors. In the first part of our study funded by the WCRF, we have identified a huge service gap in the provision of appropriate physical activity and dietary advice to bowel cancer survivors. Our bowel cancer patients were unaware of the link between physical activity and diet with treatment outcome but most demonstrated acceptance to lifestyle modification. Our review of the medical literature also showed minimal information on the effect of lifestyle intervention on bowel cancer survivors. As a result, one cannot give any scientifically-based advice on how bowel cancer survivors may improve their outlook by lifestyle changes.
This proposed study aims to test the feasibility of two behavioural changes in bowel cancer survivors, namely (1) increase in physical activity level (to 60 minutes of moderate physical activity five days a week); and (2) reduce consumption of a Western diet to preset levels (i.e. < 5 servings of red/processed meat every week and 2 servings of refined grains daily).
A feasibility study will be conducted on 224 bowel cancer survivors from 4 public hospitals in Hong Kong. Patients who have completed their cancer treatment within the previous 12 months and without residual disease would be invited to participate. They would be randomly allocated to one of the four groups, that is, (1) no intervention (control); (2) physical activity intervention only; (3) dietary intervention only; and (4) both dietary and physical activity interventions. The intervention would last for 12 months and the subjects would be followed up for a further 12 months. The outcomes to be determined include (1) rates of meeting the two behavioural targets, (2) levels of behavioural change, (3) compliance rate and factors affecting compliance; (4) factors facilitating and preventing behavioural change; (5) psychosocial factors (according to adopted theories) influencing the process of behavioural change; (7) possible health benefits associated with behavioural change and (7) possible side effects associated with behavioural change. These outcomes will be assessed periodically during and up to 12 months after completion of the intervention.
To the best of our knowledge, this is the first behavioural modification study targeting increase in physical activity level and reduced consumption of a Western diet in bowel cancer survivors. If proven feasible, our intervention model would facilitate the launch of a large-scale scientific study (called a randomized controlled trial) to formally determine the effect of physical activity and diet on the treatment outcome of bowel cancer survivors.