Self-Determination Theory-informed Occupational Therapy Program to Increase Physical Activity Among Survivors of Breast Cancer

Breast cancer (BC) survivors, defined as those ever diagnosed with BC through the end of life, totaled approximately 4 million people in the U.S. in 2022. While the 5-year survival rate across all races for BC is 90%, functional limitations associated with BC treatment often have considerable impacts on BC survivors' physical and mental health-related quality of life (HRQoL). Approximately 90% of women diagnosed with non-metastatic BC undergo breast-conserving surgery or mastectomy. These surgical interventions commonly lead to upper extremity impairment, decreased strength, and limited mobility, contributing to long-term declines in objectively measured physical function, one key determinant of HRQoL. Moreover, BC survivors' functional limitations can limit participation in health promoting behaviors (e.g., aerobic physical activity [PA]; muscle strengthening exercise [MSE])-limitations that have been shown to place this population at increased morbidity and premature mortality risk. It is therefore critical to develop accessible programs that allow BC survivors who have undergone breast-conserving surgery or mastectomy to reduce functional limitations and more readily engage in health promoting behaviors contributing to improved HQRoL.

Physical activity is safe and beneficial for most cancer survivors, and can improve HRQoL via increased self-efficacy and physical, emotional, social, and functional well-being. More specifically, aerobic PA has been shown to have a positive impact on multiple aspects of BC survivors' health, including cardiorespiratory fitness and fatigue levels. Recently, MSE has been established as a critical health-promoting behavior for reducing the functional limitations associated with BC treatment. MSE also contributes to improved cardiorespiratory fitness and overall metabolic health. However, less than 20% of BC survivors meet recommended aerobic PA and MSE guidelines. Qualitative research highlights that BC survivors who have undergone breast-conserving surgery or mastectomy are uncertain about integrating aerobic PA and MSE into their lives after transitioning out of formal care settings. Support is needed to help this population with lingering functional limitations transition into sustained, self-directed PA and MSE in community- and home-based settings.

Occupational therapy (OT) is uniquely capable of addressing the barriers to sustained PA faced by BC survivors who have undergone breast-conserving surgery or mastectomy. The goal of OT for cancer survivors is to return to activities of daily living following cancer treatment. As such, OT is a critical post-treatment component for BC survivors. Occupational therapists are trained in behavior change techniques, remediation of functional impairments, and modification of activities and environments. This training uniquely positions occupational therapists to provide the specialized aerobic PA and MSE programming that can support BC survivors' health behavior initiation and maintenance. Further, this skillset may be particularly conducive to promoting long-term adherence to aerobic PA and MSE, as OT emphasizes the primacy of building clients' capacity to engage in behaviors that are congruent with personally held values and preferences. Emerging evidence suggests that orienting health promotion efforts in this way supports sustained lifestyle behavior change.

OT-based PA programming for BC survivors can be grounded in Self-Determination Theory (SDT) to support sustained, self-directed PA. SDT posits that people are oriented toward growth and development, and that the satisfaction of people's core psychological needs (i.e., autonomy, competence, and relatedness) facilitates the formation of autonomous motivations for health-related behaviors (i.e., enjoyment, interest, identity, and values). It theorizes that changes in more autonomous motivations will yield longer-lasting behavioral changes than changes in less autonomous motivations. Autonomous motivations for PA are well established determinants of long-term physical activity maintenance in multiple populations, including BC survivors. Autonomous motivations for PA can be modified by targeting core psychological needs (i.e., increasing perceptions of autonomy, competence, and relatedness). Importantly, SDT has been proposed as an ideal theoretical framework for guiding OT. OT is centered on building client's capacity to engage in personally defined goals and occupations (targeting perceptions of autonomy). Occupational therapists scaffold learning and apply therapeutic techniques centered on helping clients experience incremental successes toward achieving their goals (competence); they also prioritize establishing an autonomy-supportive, therapeutic alliance with their clients (relatedness). It is through these mechanisms of action that we expect our program to yield sustained increases in aerobic PA/MSE for BC survivors.

Digitally mediated occupational therapy (OT) is uniquely suited to helping BC survivors transition to sustained community- and home-based physical activity after undergoing breast surgery dramatically increasing the accessibility of expert-provided PA/MSE programing. OT programs conducted in formal settings are often associated with low adherence and face marked barriers to implementation, including lack of access to care and transportation-related barriers. These barriers are most pronounced in rural BC survivors-particularly relevant to the target population of the current proposal; in 2020, 33% of Oklahomans lived in areas designated as 'rural' by the U.S. Department of Agriculture (USDA) Economic Research Service (ERS). The use of digital technologies, such as telehealth, can help rural and urban BC survivors circumvent these challenges to receiving OT programming. Emerging evidence suggests that technology-mediated OT is feasible for urban and rural BC survivors. Yet, more research is needed to understand if a telehealth-delivered OT program based on the tenets of SDT and focused on promoting post-surgery aerobic PA and MSE will be acceptable and feasible to urban and rural BC survivors. We propose to investigate the acceptability, feasibility, and safety of a novel 8-week OT program among urban and rural BC survivors (N = 30) that combines 1) 8 telehealth-delivered sessions with an occupational therapist and 2) self-regulatory strategies known to support PA adoption and maintenance.1 Study observations will contribute valuable insights regarding how to scale telehealth-delivered OT programs to improve PA adherence and PROs among urban and rural BC survivors-ultimately helping improve HRQoL.

We will investigate the acceptability and feasibility of a novel 8-week OT program among 30 rural and urban BC survivors that features: 1) 8 weekly telehealth OT sessions, and 2) self-regulatory strategies known to support aerobic PA and MSE adoption and maintenance, emphasizing components of the SDT, and the provision of a wearable device (e.g., a fitness tracker) programmed to supplement individually tailored goals. We have the following Specific Aims, Hypotheses, and Milestones:

Aim 1: Assess participants' perceptions of the acceptability, usability, and usefulness of the SDT-grounded, OT-based PA/MSE program (hereafter 'program'). Hypothesis 1: Participants will report the program's components to be acceptable, useable, and useful. Milestone 1a: Thematic analyses of qualitative data will suggest the program was enjoyable and improved physical and mental well-being. Milestone 1b: Quantitative assessments of the program via the System Usability Scale will average scores >68-indicative of 'above-average' program usability and usefulness.

Aim 2: Evaluate program feasibility and safety. Hypothesis 2: The program will be feasible and safe as demonstrated by satisfactory participant retention and adherence to program components and no unexpected increases in adverse outcomes. Milestone 2a: At least 80% of participants who complete baseline measures will subsequently complete post-program measures Milestone 2b: Participants will average ≥80% attendance at OT sessions. Milestone 2c: Frequency of BC-related lymphedema, musculoskeletal injuries, and any adverse events will be below normative values-indicative of a safe program.

Exploratory Aims: Evaluate pre- to post-program changes in 1: SDT-related constructs as key mechanisms of action; 2: aerobic PA and MSE; and 3: patient-reported outcomes (PROs) and goal attainment. Exploratory Hypotheses: Pre- to post-program changes in SDT-related components, aerobic PA and MSE behaviors, and PROs/goal attainment will be favorable. Milestone 3a: Measures of perceived autonomy, competence, and relatedness-key SDT components in the context of PA/MSE-will improve from pre- to post-program. Milestone 3b: Participants will demonstrate aerobic PA increase of ≥10 minutes/day and will engage in at least two MSE bout per week by post-program. Milestone 3c: An average pre- to post-program change of 2-6 T-score points, dependent on the PRO being assessed, as measured by the Patient-Reported Outcomes Measurement Information System (PROMIS), with most participants achieving their pre-program goals by post-program.