Barriers to physical activity levels in people with cancer who are undergoing chemotherapy: a narrative systematic review with mapping to the capability, opportunity, motivation behaviour (COM-B) model

Purpose: Cancer is a leading cause of death and disability. Chemotherapy is one of the most common treatments. Physical activity (PA) can improve chemotherapy side effects, fatigue, adherence, survival rates and quality of life. However, people who are undergoing chemotherapy are insufficiently active. This review aimed to identify the barriers to PA in adults who are undergoing chemotherapy for the treatment of cancer. Methods: Databases were searched for articles that met the eligibility criteria and screened to determine eligibility and risk of bias using the Clinical Appraisal Study Programme Qualitative Checklist. Studies included adults aged > 18 years who were currently undergoing chemotherapy for any type or stage of cancer. Reflexive thematic analysis was used to develop themes, which were deductively mapped to the capability, opportunity, motivation behaviour (COM-B) model and presented narratively. The behaviour change wheel intervention functions enabled identification of potential strategies to address barriers. Results: A total of 9774 articles were screened. Twenty studies were eligible, including 1085 participants. Side effects of cancer and chemotherapy, other health conditions (capability), knowledge gaps, accessibility, environmental factors, and lack of social support (opportunity); negative emotional response, not having time/prioritising other commitments, and low motivation (motivation) were identified as barriers to PA. Fatigue was the most commonly identified single barrier. Intervention functions to improve PA levels include environmental restructuring, education, training and enablement. Conclusion: The most commonly reported barriers to PA in people who are undergoing chemotherapy included side effects of cancer and chemotherapy, not having time/prioritising other commitments, knowledge and accessibility. Changes to service accessibility and delivery, and education for the cancer care team and people who are undergoing chemotherapy should be implemented to support increasing PA levels.