Leading cancer specialist Dr Lorenzo Cohen ran a clinical trial that was published this month, which revealed that women who did yoga during radiotherapy for breast cancer had a much better quality of life and better control of stress hormones.
So how did downward dog leave them feeling?
Amazingly, they had better general health, they found it easier to engage in their daily activities, and had lower levels of fatigue.
Dr Cohen - who is a professor and the director of the Integrative Medicine Program at the MD Anderson Cancer Center in Houston Texas - is interested in finding out how lifestyle affects cancer and recovery from the disease. In particular, he specialises in large-scale studies that examine the effects of practices such as yoga, meditation, tai chi and qi-gong.
He will be presenting his findings at the Yoga and Health: Research and Practice conference in early April, but we wanted to find out more about this groundbreaking study that involved 160 women with breast cancer.
What was the aim of the study?
That clinical trial was specifically to look at the benefits of incorporating yoga into the radiation treatment plan for women with breast cancer. We had done a smaller previous study using the same model comparing yoga to just standard care. But in this study what was important, and unique in comparison to all other studies of yoga in cancer, was that in addition to the standard care control group we also included a stretching control group.
The stretching and yoga participants - who were receiving radiotherapy treatment - did it three days a week for one hour each time for the 6 weeks of radiotherapy. We collected data before the start of radiotherapy and then again at the end and 1, 3, and 6 months later.
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What did you find?
After finishing radiation treatment, which is linked with fatigue, only the yoga and stretching groups reported feeling less tired.
Over time, however, only the yoga group had benefits in physical functioning and general health perceptions, and better regulation of the stress hormone cortisol than the other two groups; with differences lasting as far as six months after the end of radiotherapy
Why the difference between the yoga and the stretching group?
So what’s interesting about yoga is that it incorporates physical movements and postures (asanas), controlled regulated breathing, as well as aspects of relaxation and meditation. Most importantly, one of the goals is to synchronise the body, breath and mind.
The origins of the Sanskrit word Yoga means to yoke or to join or union – the joining of mind and body.
With standard exercise there wasn’t an incorporation of breath and the mind. It was more mechanical stretching to help stretch muscles post-surgery.
So what our findings suggest is that this more comprehensive mind-body approach, following the roots of yoga, clearly leads to more beneficial effects than simple stretching alone. But it needs to be studied further and the ongoing phase III clinical trial involves 600 patients using a similar model, where the stretching control group will also learn some simple relaxation techniques.
Obviously yoga won’t cure cancer, but can it affect biological functioning ?
Our study found that by the end of radiotherapy and one month later, the women in the yoga group had better regulation of the stress hormone cortisol (steepest downward slope across the day). Previous research has found that better diurnal regulation of cortisol (steeper slope) was predictive of longer survival in breast cancer patients with stage IV disease.
We’ve found the same thing in kidney cancer patients with stage IV disease. People with less steep or blunted cortisol slopes don’t live as long.
Chronic stress can lead to biological changes in the body impacting the immune system as well as having direct impact on the tumour microenvironment. These could lead to worse survival, so programs that help patients to manage stress may be very useful. A recent yoga study in breast cancer survivors found that yoga led to improvements in immune function.
With that said, there hasn’t been specific research to document that mind-body interventions increase survival, but studies show that factors like depression shorten survival time.
So stress is a killer?
We know chronic stress has a profound impact on quality of life and negatively affects all biological systems in the body. Now we have research that shows that stress can get right into the nucleus of every cell in the body, modifying gene expression, shortening telomeres (related to the aging process), and activates cancer-related pathways.
Studying stress in humans is difficult because of the challenges around the definition of stress and measuring stress. But animal research on stress and cancer shows that stress can increase vulnerability to cancer and progression of disease, and is documenting that stress clearly impacts the tumour microenvironment making it more hospitable to cancer growth.
To find out more about the Yoga and Health: Research and Practice conference, which takes place on 4,5 and 6 April, click here. It is run by The Minded Institute.