Breast cancer is the most common cancer disease in women. As the prevalence of fatigue is high in this group it is motivated to find interventions that can reduce fatigue and render in an increased level of physical activity both during and after treatment. Yoga have shown effect on cancer related fatigue (CRF) and is a rehabilitation activity that is often requested by breast cancer patients. Breast cancer patients live in cites and small-towns as well as in rural areas and therefore there is a need for accessible rehabilitation activities for all patients despite place of residence.

A digitally distributed yoga class can potentially increase accessibility for those living in rural areas.

Aim

The overarching aim of this study is to investigate the effect of a 12-weeks digitally distributed yoga intervention for women treated for breastcancer, compared with a control group receiving regular care, concerning:

• patient reported outcomes, primary endpoint CRF
• systemic inflammation
• activity level

The study will evaluate if there are differences during and after the intervention and if those differences are sustained after 1, 3, 6, 12 and 24 months after the intervention.

Additional objectives are to compare the two groups concerning completing oncologic treatment, cost effectiveness, return to work and also to describe the patients experiences of participating in a digitally distributed yoga class at home.

Research questions

If and how a digitally distributed yoga can influence cancer related fatigue, stress, health related quality of life and level of physical activity compared to regular care? If and how a digitally distributed yoga can have an effect on systemic inflammation? How is the feasibility of digitally distributed yoga twice weekly at home? What is the breast cancer patients' experience of participating in digitally distributed yoga clas?

Study design and Setting

This is a randomized controlled multi center study where the participant are randomized to a 12-weeks internet based yoga intervention or regular care. Usual care includes standardized information about the importance of physical activity in their personal care plan.

Three regions located in the middle of Sweden is reqruiting participants and two moore is in the process of starting reqruitment.

From January 2022 permission to reqruit through social media and direct adverticement began, after permission was granted from the ethical board.

Inclusion criteria: Adult women diagnosed with breast cancer, that have undergone breast cancer surgery within 60 days with curative intention, without any signs of metastatic disease, and before start of chemotherapy. They should be Swedish speaking and literate.

Exclusion criteria: If they received neoadjuvant treatment before surgery, have an advanced recurrent disease, unstable cardiovascular disease, brain or bone metastasis or are unable to complete the questionnaires due to reduced physical or cognitive capacity. If they have any physical condition that hinder participation in yoga or have an unstable medical condition that might be aggravated by yoga.

Randomization:

The patients are randomized after their first visit to the oncologist. In an web-based digital portal, a digital randomization are conducted. The stratified randomization will be according to surgery, Breast-Conserving Surgery (BCS) versus mastectomy (ME), chemotherapy versus no chemotherapy.

Yoga Intervention:

To minimize the ambiguities in design found in previous studies, the yoga intervention is designed according to Sherman's recommendations. The yoga postures and movements will be chosen specifically to address this group of patients.

1. Type of yoga: Physical yoga sequences that through scientific evaluation have proven to be effective and relevant for the target group, ended by relaxation and time for reflection. There are two different programs during the 12-week-intervention. Easy-access sequences that can suit all (with modifications if needed), no progression but the programs can offer a small variation of movements over the intervention period.
2. Dose: twice weekly for 12 weeks; one yoga class live broadcasted and digitally distributed to the patient's computer or mobile device, and one class pre-recorded video for self-training.
3. Components of yoga: The yoga class will follow a standardized program with yoga sequences that is designed to increase calm, improve focus, acceptance and energy level as well as reduce fatigue.
4. Sequences: The yoga class will be 60 minutes including 10 minutes of final relaxation. Thereafter, a 5 minutes reflection will be offered.
5. Modification: Modification of yoga movements will be offered by the instructors based on the personal conditions of the participants. In the pre-recorded video the instructor will give a number or alternatives when relevant.
6. Selection of instructors: The yoga instructors have previous experience of teaching yoga, ie is registered yoga teachers with 100 respectively 200-hour training. They have attend a one-day course administered by the research team consisting of lectures and seminars about cancer and cancer treatment, the aim and design of the study, theory, and instructions regarding the yoga programs including modifications and technical aspects regarding digital distribution of the intervention.
7. Home Training: Instructions for yoga home practice will be standardized. The yoga programs will be distributed in video-links for the participants to view at a time-point that suits them during the week. The recommendation will be to yoga at home once a week in addition to the digital yoga class in real time.
8. Presence over time: Attendance will be noted through login data. Adherence to activity will be calculated as the number of patients conducting 65% of the sessions, divided by the total number of patients in the group.

Technical solution:

Participants are expected to use their own computer or mobile device. The streaming is be arranged through Zoom® . Written information and help to connect is provided weekly as well as personal support when needed.

Control group:

All breast cancer patients receives written standardized information about the importance of physical activity by their contact nurse or physiotherapist, when discharged from the hospital accordingly to the routines at the clinic.

Sample size estimation:

The sample size calculation is based on the outcome fatigue. The target main effect size is determined to be an improved fatigue score of 2 on a scale from 4 to 20. That is in accordance with the clinical important difference. For two-sided test with α=0.05 and power =80% to detect a factorial effect of 2 under the null hypothesis of no effect, 64 individuals in each group are needed. In order to compensate for a potential 30% dropout, the sample size will be increased with an additional 39 persons, giving a total sample size of 67 patients. To detect interaction effects that is usually smaller than the main effect, the original sample size was increased with 25% (~42 patients). This gives a total of 209 patients divided into 2 arms; intervention and control. To cover up for any other possible dropouts a total of 240 perons will be included.

Data collection:

Data are collected at baseline (one month after surgery) and 3, 6, 24 and 48 months after breast cancer surgery. Self-reported data (questionnaires) are collected each time (5 times), activity levels (accelerometer) at the first three follow-ups and at 12 months.

Diary of physical activity is reported in conjunction with the measurements with accelerometer.

Blood samples will be collected from 40 patients reqruited through hospitals at the first three follow-ups.

Health economic evaluation:

The health economic evaluation will be performed with a societal as well as a health care perspective and consider time period from baseline to one year after the interventions had ended. Cost effectiveness will be presented in costs per quality adjusted life years (QALY), but also as a probability of cost-effectiveness compared to usual care.

Main components in the analysis are extra costs of the interventions, changes in QALY and savings of the interventions. Saving may be less time on sick leave (less production losses) and less health care consumption. Complete costs of the interventions for the health care provider and for patients will be measured. Further, QALY will be estimated using the instrument EQ-5D-5L, time on sick leave will be collected in the questionnaire to participants, and health care consumption will be retrieved from medical records.

Inclusion Criteria:

Clinical diagnosed with breast cancer Adult women Must have undergone breast cancer surgery with curative intention Must be Swedish speaking Must be able to read

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Exclusion criteria:

Metastatic disease Received neoadjuvant treatment before surgery Advanced recurrent disease Unstable cardiovascular disease Brain or bone metastasis Unstable medical condition that might be aggravated by yoga.