Motivational Interviewing to Increase Physical Activity Behaviour in Cancer Patients

Physical activity is not only efficient for primary prevention of several cancer types, but it also plays an important role in cancer survivors. Physical activity after a cancer diagnosis has been associated with reduced overall and cancer-specific mortality. It has significant positive effects on physical fitness and several cancer-related symptoms including fatigue, sleep disturbance, depression and anxiety. The evidence is considerable and consistent for breast, colorectal and endometrial cancers. However, patients are generally insufficiently active, and participation rates in physical activity opportunities offered by specialized organizations are low. This pilot study will evaluate the feasibility, efficacy and cost-effectiveness of an intervention seeking to increase active lifestyle and physical activity participation of cancer patients. To encourage this behavioural change, motivational interviewing will be used, a patient-centred approach aimed at increasing the patients' motivation for a behavioural change through open-ended discussions. Seventy patients with breast, colorectal or endometrial cancer will be recruited within a time period of 12 months. Patients will be randomly assigned to an intervention or a control group. The intervention group will receive standard care alongside 12 motivational interviewing sessions within 12 weeks. The control group will receive standard care only. Physical activity behaviour (3D-accelerometer) and physical fitness (cardiovascular and strength fitness) will be measured in the week preceding and following the intervention. Additionally, a subgroup from both study arms will be assessed 12 weeks after the completion of the intervention. The investigators hypothesize that sedentary time will decrease and time spent in moderate and vigorous physical activity, physical fitness and quality of life of cancer survivors will increase to a greater extent in the intervention group than in the control group. Furthermore, health-