Promoting Physical Activity in Breast Cancer Survivors on Aromatase Inhibitors

Promoting Physical Activity Through Supervised vs Motivational Behavior Change Interventions in Breast Cancer Survivors on Aromatase Inhibitors (PAC-WOMAN): A 3-arm Pragmatic Randomized Controlled Trial

Aromatase inhibitors (AI) are frequently used to treat hormone-receptor-positive breast cancer, but they have multiple adverse effects (eg, arthralgia), resulting in premature therapy discontinuation/switch. Physical activity (PA) can attenuate these negative effects and improve quality of life (QoL). However, most cancer survivors fail to perform/sustain adequate PA levels, especially in the long-term. Theory-based interventions, using evidence-based behavior change techniques, aimed at promoting long-term behavior change in breast cancer survivors are effective, but remain scarce and fail to promote self-regulatory skills and better-quality motivations associated with sustained PA adoption.

PAC-WOMAN will test the long-term effectiveness and cost-effectiveness of two state of the art, group-based interventions encouraging sustained changes in PA, sedentary behavior, and QoL. Additional aims include examining the impact of both interventions on secondary outcomes (eg, body composition, physical function), and key moderators/mediators of short and long-term changes in primary outcomes. A 3-arm pragmatic randomized controlled trial, involving a 4-month intervention and a 12-month follow-up, will be implemented, in a real exercise setting, to compare: 1) brief PA counseling/motivational intervention; 2) structured exercise program vs. waiting-list control group. Study recruitment goal is 122 hormone-receptor-positive breast cancer survivors (stage I-III), on AI therapy (post-primary treatment completion) ≥1 month, performance status 0-1. Outcome measures will be obtained at baseline, 4 months (i.e., post-intervention), 10 and 16 months. Process evaluation, analyzing implementation determinants, will also be conducted.

PAC-WOMAN is expected to have a relevant impact on participants PA and QoL, and on the improvement of interventions designed to promote sustained adherence to active lifestyle behaviors, facilitating its translation to community settings.

Aromatase inhibitors (AI) are frequently used to treat hormone-receptor-positive breast cancer, but they have multiple adverse effects (eg, osteoporosis, arthralgia), resulting in premature therapy discontinuation/switch. Physical activity (PA) is safe and should be an integral and continuous part of care for all individuals diagnosed with cancer. There is compelling evidence suggesting that PA plays an important role in improving longevity among cancer survivors. PA effectively ameliorates short- and long-term adverse effects of cancer therapies (eg, comorbid conditions, improves physical fitness and function, attenuates cancer-related fatigue, enhances body image and quality of life (QoL), and decreases cancer recurrence and mortality. PA also allows women to benefit from endocrine therapy while being protected against the related risk of osteoporosis, fracture, and ultimately cancer recurrence or death. Thus, PA in breast cancer survivors, and specifically among women on AIs, is paramount to improve health outcomes, QoL, and prevent therapy discontinuation. However, most cancer survivors fail to meet established guidelines for PA.

Theory-based interventions, using evidence-based behavior change techniques, aimed at promoting long-term health behavior change in breast cancer survivors are effective, but remain scarce and predominantly focused on short-term adherence/outcomes. Also, most interventions fail to provide validated self-regulatory tools or explore meaningful links between PA and patients' values and life aspirations to foster lasting behavior changes. Prior research has shown that internal (better quality) forms of motivation play an important role in PA and behavior sustainability, suggesting that self-determination theory (SDT) can be a valid framework to promote sustained adherence to PA. A need-supportive intervention climate enhances people's wellbeing and their ability to self-regulate and sustain behavior changes. Finally, skills such as self-monitoring, goal setting or action planning have also been identified as important mediators of long-term PA and as core features of effective behavior change/maintenance interventions in breast cancer survivors.

In sum, although regular PA is a promising and safe way of helping cancer survivors navigate their disease, alleviating the growing pressure on the health care system, most cancer survivors do not meet the recommended PA doses. It is a goal of this project to overcome the abovementioned shortcomings, by testing an intervention model informed by solid evidence and a robust theoretical rationale (SDT), provided by qualified exercise professionals, which appear to add value to the treatment process, improving the therapeutic effect and safety of the exercise practice.

PAC-WOMAN will test the long-term effectiveness and cost-effectiveness of two 4-month group-based interventions aimed at promoting sustained changes in PA, sedentary behavior, and QoL. Additional aims include examining the impact of both interventions on secondary outcomes (eg, body composition, physical function), and key moderators and mediators of short and long-term changes in primary outcomes. A 3-arm randomized controlled trial, involving a 4-month intervention period and a 12-month follow-up, will be implemented to compare: 1) a brief PA counseling intervention; 2) a structured exercise program; and 3) a. waiting-list control group. Study recruitment goal is 122 breast cancer survivors with hormone-receptor-positive breast cancer (stage I-III), on AI therapy (post-primary treatment completion) for at least 1 month, ECOG performance status 0-1. Outcome measures will be obtained at baseline, 4 months (i.e., post-intervention), 10 and 16 months. Process evaluation, analyzing implementation determinants, will also be conducted.

PAC-WOMAN is expected to have a relevant impact on the improvement of interventions designed to promote sustained adherence to active lifestyle behaviors and facilitate its translation to community settings.

Inclusion Criteria:

1. post-menopausal women, below 70 years old;
2. histologically confirmed hormone-receptor-positive breast cancer (stage I, II, III);
3. having initiated aromatase inhibitor hormonal therapy following the primary treatment (surgery, radiotherapy, chemotherapy, etc.), at least 1 month before being enrolled;
4. ECOG-Performance Status 0-1.

Exclusion Criteria:

1. evidence of stage IV cancer or synchronous tumors;
2. uncontrolled hypertension, cardiac or pulmonary disease;
3. contraindications to exercise training according to the assistant doctor;
4. inability to provide informed consent;
5. expected inability to fulfill the proposed schedule.