Breast CancerCOBRANCT06480513
Cancer Of the BReast Asanas Study (COBRA)
A study testing live yoga and live remote yoga in people with Breast Cancer, run by UMC Utrecht at 1 site in Netherlands.
Trial summary
Rationale: Women with hormone-receptor positive breast cancer are usually prescribed endocrine therapy for a period of 5-10 years. This treatment reduces the risk of recurrence and improves overall survival in these women. Read more about this study
- Who is it for?
- Any age, women only
- Conditions the study is for
- Breast Cancer
- What is being tested?
- live yoga and live remote yoga
- Type of treatment
- Lifestyle or therapy programme
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 140 participants
- Where
- 1 siteNetherlands
- Study dates
- 8 Oct 2024to Jun 2027
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages Any age
- Women only
- No healthy volunteers
- Child, Adult, Older adult
Who may be able to join
- Be diagnosed with oestrogen-receptor positive stage I-III breast cancer,
- Use of aromatase inhibitors or Tamoxifen (>4 months and will continue using it for at least six months),
- Have finished primary treatment (chemotherapy, radiotherapy, surgery) for at least 12 weeks,
- Experience musculoskeletal complaints (>3 months, which are at least mild in severity (i.e., score of ≥ 3 for worst pain item of a modified version of the Brief Pain Inventory [BPI](16, 42))., which started or exacerbated after initiation of endocrine treatment,
- Be stabilized on menopausal symptom medication or antidepressants for at least three months and three weeks, respectively, if applicable, and
- Be able to read, speak and understand Dutch or English.
Who cannot join
- Too physically active (i.e., >150 minutes/week of self-reported moderate-to-vigorous or leisure and sports activities)
- Following (during the last 6 months), or planned to follow yoga classes on a structural base
- Following, or planned to follow, a structured psychological intervention during the intervention period, i.e., cognitive behavioral therapy, or unstable on psychotropic medication
- Participated in the intervention group of an exercise study during breast cancer treatment
- Any circumstances that would impede ability to give informed consent or adherence to study requirements as determined by the study team
- More than 3 weeks not able to attend training sessions during the intervention period
- A body mass index (BMI) of >35 kg/m2
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Netherlands1 site, 1 recruiting
- Recruiting
University Medical Center Utrecht (UMC Utrecht)
Utrecht, 85500 3508 GA
Stefanie Veenhuizen, MSc, +31 6 31 11 91 29, s.g.a.veenhuizen@umcutrecht.nl
About this study
Official title: The Effect of Yoga on Endocrine Therapy Induced Musculoskeletal Symptoms in Women With Breast Cancer: the COBRA Study
Rationale: Women with hormone-receptor positive breast cancer are usually prescribed endocrine therapy for a period of 5-10 years. This treatment reduces the risk of recurrence and improves overall survival in these women. Musculoskeletal complaints are a common (~50%) negative consequence of endocrine treatment, which affects daily functioning and quality of life. These symptoms frequently result in early treatment discontinuation, which is associated with shorter disease-free survival. Musculoskeletal complaints are often pharmacologically treated with limited effect and accompanied by side-effects. Therefore, interventions to counteract musculoskeletal complaints are urgently needed in this population. A potential non-pharmacological option is yoga. In patients with osteoarthritis, there is emerging evidence that yoga is effective to reduce pain and stiffness and improve function. Yoga as treatment for musculoskeletal complaints that are associated with endocrine treatment is rarely investigated and mainly in small studies.
Objective: The objective of the proposed study is to assess the effectiveness of a 4-month yoga program compared to a waiting list control group on musculoskeletal complaints in women with hormone-positive stage I-III breast cancer receiving endocrine treatment who report musculoskeletal complaints.
Read more
Study design: The COBRA study is a randomized controlled trial with two study arms: a yoga- and a waiting list control group.
Study population: For this study, 140 women with oestrogen-receptor positive stage I-III breast cancer on endocrine treatment (aromatase inhibitors or Tamoxifen; >4 months) will be recruited. These women experience musculoskeletal complaints (>3 months) which started or exacerbated after initiation of endocrine treatment. Furthermore, eligible women did not practice yoga in the last six months and are not planning to start yoga and are not highly physically active (i.e., >150 minutes per week moderate-vigorous exercise).
Intervention: The intervention consists of two one-hour sessions/week supervised yoga and once a week 30-minute yoga exercises at home. The 4-month yoga program will be an active form of yoga, such as Easy Vinyasa yoga, which is characterized by continuous slow movements linked with breathing. The waiting list control patients will be offered an online yoga program after the 4-month study period.
- Conditions
- Breast Cancer
- Being tested
- live yoga, live remote yoga
- Medical subject headings
- Breast Neoplasms
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
live yogaBehavioural
following live yoga classes twice a week and using yoga video's at home once a week
live remote yogaBehavioural
The control group will be offered live remote yoga classes after the intervention period
| Study group | Role | What they receive |
|---|---|---|
| yoga group | Experimental | following live yoga classes twice a week and using yoga video's at home once a week Receives: Behavioral: live yoga |
| control group | Other | Waiting list control group. The control group will be offered live remote yoga classes after the intervention period Receives: Behavioral: live remote yoga |
What is being measured
The primary outcome is the main question the study is designed to answer.
Musculoskeletal complaints
Worst of joint pain and stiffness/joint pain and stiffness severity/joint pain and stiffness interference assessed by the modified version of the BPI.
The 14-item questionnaire result in three domain scores: worst pain/stiffness, pain/stiffness severity, and pain/stiffness interference over the past week, on a scale of 0 to 10. All these three domain scores of the BPI will be primary outcomes which will be tested sequentially to preserve an alpha of 0.05. The order of the sequential testing is: 1) worst pain/stiffness, 2) pain/stiffness severity and 3) pain/stiffness interference.
Measured: Baseline, at 4 and 8 months
Secondary outcomes (23)
Lower extremity joint complaints
Using the WOMAC questionnaire
Measured: Baseline, at 4 and 8 months
Upper extremity musculoskeletal complaints
Using the DASH questionnaire
Measured: Baseline, at 4 and 8 months
Menopausal symptoms
Using the FACT-ES questionnaire
Measured: Baseline, at 4 and 8 months
Fatigue
Using the MFI questionnaire
Measured: Baseline, at 4 and 8 months
Sleep
Using the PSQI questionnaire
Measured: Baseline, at 4 and 8 months
Health-related Quality of Life (HRQoL)
Using the QLQ-C30 that has functional scales, symptom scales and a global quality of life (QOL) score. A high score for a functional scale represents a high/ healthy level of functioning, a high score for the global health status/QoL represents a high QoL, but a high score for a symptom scale/item represents a high level of symptomatology/problems.
Measured: Baseline, at 4 and 8 months
Health-related quality of life (HRQoL)
Using the BR45. The QLQ-BR45 incorporates nine multi-item scales to assess body image, sexual functioning, breast satisfaction, systemic therapy side effects, arm symptoms, breast symptoms, endocrine therapy symptoms, skin mucosis symptoms, endocrine sexual symptoms. All items are scored 1 to 4.
Measured: Baseline, at 4 and 8 months
Anxiety and depression
Using the Hospital Anxiety and Depression Scale (HADS) where anxiety and depression are measured separately on a scale from 0-7 (Normal), 8-10 (borderline abnormal) and 11-21 (abnormal).
Measured: Baseline, at 4 and 8 months
Cognitive functioning
Using the Amsterdam Cognition Scan
Measured: Baseline and at 4 months
Cognitive functioning
Using the FACT-COG
Measured: Baseline, at 4 and 8 months
Physical activity
Using the Short Questionnaire to Assess Health-enhancing physical activity (SQUASH). Physical activity is measured in minutes per week.
Measured: Baseline, at 4 and 8 months
Blood markers
Inflammatory markers (Interleukin-6 and Interleukin-IB, tumor necrosis factor alpha (TNF-alpha) and high-sensitive C-reactive protein (hsCRP). At the end of the study we will conduct a literature review to identify the most promising biomarkers.
Measured: Baseline and at 4 months
Physical strength
Hand grip strength using a handgrip dynamometer. The best of three attempts will be recorded.
Measured: Baseline and at 4 months
Physical strength
Leg press using a hypothetical 1-RM test
Measured: Baseline and at 4 months
Physical strength
Plank position holding time test for core strength
Measured: Baseline and at 4 months
Vital signs
Blood pressure and resting heart rate
Measured: Baseline and at 4 months
Anthropometrics
Weight and height will be combined to report BMI in kg/m^2. Waist- and hip circumference.
Measured: Baseline and at 4 months
Physical fitness
Steep ramp test using a cycle ergometer
Measured: Baseline and at 4 months
Physical fitness
Balance is measured with the Short-Form Fullerton Advanced Balance (S-FAB) scale. This scale consists of four items: stepping up onto and over a 6-inch bench, a tandem walk, standing on one leg, and standing on foam with the eyes closed. The items are rated from 0 (unable to complete the task) to 4 (completed the task perfectly), and the scores are summed up to a total score (0-16).
Measured: Baseline and at 4 months
Safety of the yoga intervention
(Serious) adverse events potentially related to the intervention
Measured: 0-8 months (whole study period)
Use of pain medication
Assessed with the BPI, questioned during the baseline and T1 visit, and self-reported with a diary
Measured: 0-8 months (whole study period)
Compliance with endocrine treatment
Self-reported with a diary
Measured: 0-8 months (whole study period)
Qualitative outcome
Patient and teacher experiences with in-depth interviews
Measured: During or after the study
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted28 Jun 2024
- Study start8 Oct 2024
- Primary completionJun 2027 (estimated)
- Study completionJun 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for Breast CancerStudies of the same condition, open and under way.
- More trials run by UMC UtrechtThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Supportive care
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Enrolment
- 140 participants (estimated)
Sponsor and investigators
- Lead sponsor
- UMC Utrecht
- Sponsor type
- University, hospital or other
- Collaborators
- World Cancer Research Fund International
- Responsible party
- Principal investigator, Dr. Evelyn Moninkhof, UMC Utrecht
- Investigators
- Anne May, Prof. Dr., Study director, UMC Utrecht
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06480513
- Sponsor's protocol ID
- 24-054/G; NL86325.041.24
- Acronym
- COBRA
- Status last verified
- Apr 2026
- First submitted
- 12 Jun 2024
- Last updated
- 6 May 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided
Publications
Veenhuizen SGA, Gal R, Cramer H, Bijlsma RM, Blickle P, van der Palen J, Wagenaar QRCM, van Leer E, Konings I, van den Bongard DHJG, May AM, Monninkhof EM. Effect of yoga on musculoskeletal complaints in women during endocrine treatment for breast cancer: protocol of the randomised controlled COBRA trial. BMJ Open. 2026 Jun 9;16(6):e117251. doi: 10.1136/bmjopen-2026-117251.
PubMed 42264518
Study at a glance
From the registry record, last updated by the sponsor on 6 May 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Effect of Yoga on Endocrine Therapy Induced Musculoskeletal Symptoms in Women With Breast Cancer: the COBRA Study
- ClinicalTrials.gov ID
- NCT06480513
- Acronym / sponsor ID
- COBRA / 24-054/G; NL86325.041.24
- Conditions
- Breast Cancer
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 140 participants (estimated)
- Lead sponsor
- UMC UtrechtUniversity, hospital or other
- Collaborators
- World Cancer Research Fund International
- Study start
- 8 Oct 2024 (actual)
- Primary completion
- Jun 2027 (estimated)
- Study completion
- Jun 2027 (estimated)
- First posted
- 28 Jun 2024 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Rationale: Women with hormone-receptor positive breast cancer are usually prescribed endocrine therapy for a period of 5-10 years. This treatment reduces the risk of recurrence and improves overall survival in these women. Musculoskeletal complaints are a common (~50%) negative consequence of endocrine treatment, which affects daily functioning and quality of life. These symptoms frequently result in early treatment discontinuation, which is associated with shorter disease-free survival. Musculoskeletal complaints are often pharmacologically treated with limited effect and accompanied by side-effects. Therefore, interventions to counteract musculoskeletal complaints are urgently needed in this population. A potential non-pharmacological option is yoga. In patients with osteoarthritis, there is emerging evidence that yoga is effective to reduce pain and stiffness and improve function. Yoga as treatment for musculoskeletal complaints that are associated with endocrine treatment is rarely investigated and mainly in small studies.
Objective: The objective of the proposed study is to assess the effectiveness of a 4-month yoga program compared to a waiting list control group on musculoskeletal complaints in women with hormone-positive stage I-III breast cancer receiving endocrine treatment who report musculoskeletal complaints.
Study design: The COBRA study is a randomized controlled trial with two study arms: a yoga- and a waiting list control group.
Study population: For this study, 140 women with oestrogen-receptor positive stage I-III breast cancer on endocrine treatment (aromatase inhibitors or Tamoxifen; >4 months) will be recruited. These women experience musculoskeletal complaints (>3 months) which started or exacerbated after initiation of endocrine treatment. Furthermore, eligible women did not practice yoga in the last six months and are not planning to start yoga and are not highly physically active (i.e., >150 minutes per week moderate-vigorous exercise).
Intervention: The intervention consists of two one-hour sessions/week supervised yoga and once a week 30-minute yoga exercises at home. The 4-month yoga program will be an active form of yoga, such as Easy Vinyasa yoga, which is characterized by continuous slow movements linked with breathing. The waiting list control patients will be offered an online yoga program after the 4-month study period.
Study design
- Primary purpose
- Supportive care
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| yoga group | Experimental | Behavioral: live yogafollowing live yoga classes twice a week and using yoga video's at home once a week |
| control group | Other | Behavioral: live remote yogaWaiting list control group. The control group will be offered live remote yoga classes after the intervention period |
Who may qualify
- Sex
- Female only
- Healthy volunteers
- Not accepted
- Age groups
- Child, Adult, Older adult
Key inclusion criteria (6 listed)
- Be diagnosed with oestrogen-receptor positive stage I-III breast cancer,
- Use of aromatase inhibitors or Tamoxifen (>4 months and will continue using it for at least six months),
- Have finished primary treatment (chemotherapy, radiotherapy, surgery) for at least 12 weeks,
- Experience musculoskeletal complaints (>3 months, which are at least mild in severity (i.e., score of ≥ 3 for worst pain item of a modified version of the Brief Pain Inventory [BPI](16, 42))., which started or exacerbated after initiation of endocrine treatment,
- Be stabilized on menopausal symptom medication or antidepressants for at least three months and three weeks, respectively, if applicable, and
Key exclusion criteria (7 listed)
- Too physically active (i.e., >150 minutes/week of self-reported moderate-to-vigorous or leisure and sports activities)
- Following (during the last 6 months), or planned to follow yoga classes on a structural base
- Following, or planned to follow, a structured psychological intervention during the intervention period, i.e., cognitive behavioral therapy, or unstable on psychotropic medication
- Participated in the intervention group of an exercise study during breast cancer treatment
- Any circumstances that would impede ability to give informed consent or adherence to study requirements as determined by the study team
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| live yogafollowing live yoga classes twice a week and using yoga video's at home once a week | Behavioural | yoga group |
| live remote yogaThe control group will be offered live remote yoga classes after the intervention period | Behavioural | control group |
Primary outcome
Musculoskeletal complaints
Time frame: Baseline, at 4 and 8 months
Worst of joint pain and stiffness/joint pain and stiffness severity/joint pain and stiffness interference assessed by the modified version of the BPI. The 14-item questionnaire result in three domain scores: worst pain/stiffness, pain/stiffness severity, and pain/stiffness interference over the past week, on a scale of 0 to 10. All these three domain scores of the BPI will be primary outcomes which will be tested sequentially to preserve an alpha of 0.05. The order of the sequential testing is: 1) worst pain/stiffness, 2) pain/stiffness severity and 3) pain/stiffness interference.
23 secondary outcomes
Lower extremity joint complaints
Time frame: Baseline, at 4 and 8 months
Upper extremity musculoskeletal complaints
Time frame: Baseline, at 4 and 8 months
Menopausal symptoms
Time frame: Baseline, at 4 and 8 months
Fatigue
Time frame: Baseline, at 4 and 8 months
Sleep
Time frame: Baseline, at 4 and 8 months
Health-related Quality of Life (HRQoL)
Time frame: Baseline, at 4 and 8 months
Health-related quality of life (HRQoL)
Time frame: Baseline, at 4 and 8 months
Anxiety and depression
Time frame: Baseline, at 4 and 8 months
Cognitive functioning
Time frame: Baseline and at 4 months
Cognitive functioning
Time frame: Baseline, at 4 and 8 months
Physical activity
Time frame: Baseline, at 4 and 8 months
Blood markers
Time frame: Baseline and at 4 months
Physical strength
Time frame: Baseline and at 4 months
Physical strength
Time frame: Baseline and at 4 months
Physical strength
Time frame: Baseline and at 4 months
Vital signs
Time frame: Baseline and at 4 months
Anthropometrics
Time frame: Baseline and at 4 months
Physical fitness
Time frame: Baseline and at 4 months
Physical fitness
Time frame: Baseline and at 4 months
Safety of the yoga intervention
Time frame: 0-8 months (whole study period)
Use of pain medication
Time frame: 0-8 months (whole study period)
Compliance with endocrine treatment
Time frame: 0-8 months (whole study period)
Qualitative outcome
Time frame: During or after the study
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 6 May 2026.
- Derived from this study: PubMed 42264518Veenhuizen SGA, Gal R, Cramer H, Bijlsma RM, Blickle P, van der Palen J, Wagenaar QRCM, van Leer E, Konings I, van den Bongard DHJG, May AM, Monninkhof EM. Effect of yoga on musculoskeletal complaints in women during endocrine treatment for breast cancer: protocol of the randomised controlled COBRA trial. BMJ Open. 2026 Jun 9;16(6):e117251. doi: 10.1136/bmjopen-2026-117251.
- Individual participant dataSharing planned: Undecided
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Anne May, Prof. Dr. study director
UMC Utrecht
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing live yoga and live remote yoga in people with Breast Cancer, run by UMC Utrecht at 1 site in Netherlands.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 6 inclusion and 7 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 6 May 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Netherlands. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Evelyn Monninkhof, Dr. (+31623786177, e.monninkhof@umcutrecht.nl), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Musculoskeletal complaints (time frame: Baseline, at 4 and 8 months). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT06480513, which also lists 1 linked publication.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 6 May 2026.