Assessment of Physical Activity Engagement and Promotion Among Cancer Survivors in Cardio-Oncology Care: Qualitative Study.

Background: Cardiovascular disease and cancer are leading causes of morbidity and mortality worldwide, with cancer survivors facing elevated cardiovascular risk due to shared risk factors and cardiotoxic treatments. Physical activity (PA) is a well-established strategy to improve cardiovascular health and survivorship outcomes; however, most cancer survivors do not meet recommended PA guidelines. Understanding multilevel influences on PA engagement and promotion is essential to improving implementation in cardio-oncology care. Objective: This study aimed to examine barriers and facilitators to PA engagement and promotion in cancer survivorship from both survivor and medical team perspectives using the Capability, Opportunity, Motivation-Behavior (COM-B) framework. Methods: A descriptive qualitative study was conducted with 12 cancer survivors and 12 medical team members involved in oncology care. Semistructured interviews explored experiences, perceptions, and practices related to PA across the cancer care continuum. Rapid qualitative analysis was used to identify themes, which were mapped to COM-B domains. Participants also completed surveys assessing PA, cardiovascular health (Life's Essential 8 [LE8]), and sociodemographic factors. Results: Survivors had a mean age of 65.3 (SD 12.6) years and were evenly distributed by sex. PA engagement varied, with 42% (5/12) of survivors meeting recommended guidelines. The mean modified LE8-derived cardiovascular health score was 71.3 (SD 11.9), reflecting a standardized 6-domain composite (diet, PA, nicotine exposure, sleep, BMI, and blood pressure) calculated identically for all 12 participants. Across COM-B domains, physical limitation was the most commonly reported capability barrier (12/12 survivors), while current engagement in PA was the most prevalent capability facilitator (12/12 survivors). Opportunity was shaped by access to PA resources and social support, with social environment being the most frequently cited facilitator (12/12 survivors; 9/12 medical team members) and lack of access to PA resources being the most common barrier among medical team members (9/12). Motivation reflected perceived health outcomes as the most prevalent facilitator across both groups (12/12 survivors; 7/12 medical team members), alongside competing concerns such as safety and emotional responses. Medical team members' ability to promote PA was influenced by survivor readiness, clinical context, and resource availability. Conclusions: PA engagement in cardio-oncology is shaped by dynamic interactions among capability, opportunity, and motivation across survivor and medical team member contexts. Although PA is widely valued, sustained engagement remains limited due to fluctuating symptoms, environmental constraints, and clinical uncertainties. Interventions should prioritize flexible, survivor-centered approaches and incorporate supportive clinical communication and resource alignment to enhance PA across the survivorship trajectory.