Diet and Physical Activity Intervention in CRC Survivors

Background - Colorectal cancer (CRC) incidence is increasing at an alarming rate in Hong Kong. A recent 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.

Objectives & hypothesis - 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 and (2) reduce consumption of a Western diet.

The investigators hypothesize that the proposed interventions are (1) efficacious in changing the two targeted behaviours; and (2) acceptable to CRC survivors.

Settings and methods - 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 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.

Impact - 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.

Background - 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.

Objectives & hypothesis - 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 grain 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%.

Settings and methods - 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 by questionnaire; (3) facilitators and barriers to behavioural change by questionnaire; (4) measurement of theoretical constructs underlying PA and dietary interventions by questionnaire; (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 (i.e. at baseline, 6, 12, 18 and 24 months after the start of intervention).

Impact - 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.