The Acceptability and Feasibility of a Diet and Physical Activity Intervention to Prevent Recurrence in Colorectal Cancer Survivors: a Phase 2 Study
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
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
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.
Allocation: Randomized, Intervention Model: Factorial Assignment, Masking: Open Label, Primary Purpose: Treatment
Whether the PA and dietary intake targets are met at the end of intervention;
Whether the PA and dietary intake targets are met at the end of intervention; i.e. PA group: achieve PA targets or not Dietary group: achieve dietary target or not PA + dietary group: achieve both PA and dietary targets or not Control group: achieve PA or dietary target or not
at the end of 12 months of intervention
Judy WC Ho, MBBS
Queen Mary Hospital, University of Hong Kong
Hong Kong: Ethics Committee