What is yoga? In which circumstances and how is it used in cancer?

Yoga is an established Indian philosophy with a history of 5000 years, based on the principle of achieving a spirit–mind–body balance through meditation, breath control, various postures and movement techniques. Literally meaning to unite or unity, yoga aims at the harmonious integration of the spirit, body and mind. Many people encountering yoga for the first time think it consists only of simple posture techniques. However, yoga is a multifaceted system encompassing many techniques. Its basic components are breathing techniques (pranayama), posture and movement techniques (asana), meditation (dhyana), and self-training/self-study (svadhyaya). Various types of yoga include all or some of these techniques. Not every type of yoga is suitable for everyone. For example, types requiring flexibility, such as ashtanga yoga, vinyasa yoga, bikram yoga and power yoga, may be unsuitable for some cancer patients. It is therefore important to ask about their content and choose the most appropriate yoga programs.

What is its history, and for which conditions is it used?

Yoga, an important part of Ayurveda, the traditional Indian medical system, was first described in Indian Vedic texts. Used widely in South Asia for thousands of years, this technique also began spreading rapidly in Western countries, particularly in the 80s. In December 2016, yoga was even added to the UNESCO World Cultural Heritage List. Offered widely in fitness centers for years, this technique has also begun to be practiced in experienced cancer centers in recent years.

Many studies have shown that yoga helps reduce symptoms of migraine, chronic lower back and back pain, joint pain, depression, anxiety disorders, seizures, carpal tunnel syndrome, high blood pressure, diabetes, asthma and irritable bowel syndrome. It has also been reported to help with weight control. Studies have shown that yoga helps balance basic vital parameters such as blood pressure, heart rate, breathing, metabolism and body temperature, reduces stress and thereby improves quality of life. In cancer patients too, yoga reduces problems such as pain, depression, stress, sleep disorders and fatigue, thereby making a substantial contribution to quality of life . According to some studies, it also helps patients with lung cancer by reducing shortness of breath .

How does yoga work?

Yoga aims to stimulate the parasympathetic nervous system through posture techniques, increase muscle and joint flexibility through movement techniques, support breathing and blood circulation through breathing techniques, and relax the mind and body through meditation techniques.

According to some studies, yoga practices:

Increase blood flow to the brain and stimulate dopamine release. They produce an antidepressant effect by increasing blood levels of brain-derived neurotrophic factor (BDNF), and reduce stress and anxiety by increasing GABA levels. They reduce anxiety and improve sleep quality by stimulating the parasympathetic system. Deep, relaxed abdominal breathing using breathing techniques alleviates gastrointestinal symptoms, while breath control also reduces airway hypersensitivity.

What are the results of studies on the effects of yoga in cancer patients?

According to current scientific evidence, yoga does not treat or prevent any type of cancer.

However, there is strong evidence that it reduces certain symptoms in cancer patients and improves their overall quality of life.

A meta-analysis evaluating 16 studies, published in 2012, showed that yoga reduced cancer patients’ symptoms of anxiety disorders, depression and fatigue . A review published in 2010, evaluating 10 clinical studies, concluded that yoga reduced anxiety, depression and fatigue in cancer patients and also improved sleep quality . Another study in patients with lymphoma found that those receiving yoga therapy fell asleep more quickly, could sleep longer and needed less sleep medication. A randomized clinical study published in 2013, evaluating 410 cancer patients, similarly showed that yoga improved sleep quality.

A systematic review evaluating 24 studies, published in 2017, concluded that yoga reduced depression, anxiety and fatigue in patients with breast cancer and improved their quality of life . Another systematic review comprising 23 studies, published in 2016, reported certain methodological shortcomings in existing studies and a need for well-designed studies on this subject; nevertheless, current data suggested that yoga was a promising complementary approach for patients with breast cancer. In a study published in 2015, radiotherapy was being received by 68 men with prostate cancer; men attending yoga classes reported fewer commonly experienced side effects (such asfatigue, an unhealthy sex life and urinary incontinence ) and higher quality of life. In another clinical study, following a yoga program for 49 patients with breast cancer and 10 with prostate cancer lasting 12 months, the stress hormone cortisol and inflammatory markers were observed to decrease substantially in the blood; heart rate and blood pressure also fell substantially .

A clinical study published in 2015 showed that yoga reduced breast cancer patients’ hormonal therapy-related muscle and joint pain . Another comprehensive study published in 2014, involving 163 women with breast cancer receiving radiotherapy, found that fatigue was less common in patients attending yoga classes and their overall health was better . Blood levels of the stress hormone cortisol were also lower. Another study involving 200 women with breast cancer reported that fatigue was %57 less common among those attending yoga classes than among those who did not. It also found a reduction in blood inflammation markers (IL-1, IL-6) of %20 .

A study involving 62 women with breast cancer receiving chemotherapy found that patients participating in a yoga program had less chemotherapy-related nausea and vomitingin terms of both frequency and severity. It was stated that yoga could be used as a complementary approach alongside standard antiemetic medicines to treat chemotherapy-related nausea and vomiting. In a study published in 2015, yoga reduced symptoms in women who had recovered from breast cancer but had menopause-like symptoms . Another study involving 63 overweight women who had fully recovered following breast cancer treatment found that after 6 months of yoga support, there was no significant difference in weight, but waist circumference decreased .

Yoga is not a complementary practice restricted to early-stage cancer. A study published in 2007 showed that yoga in women with advanced breast cancer reduced pain and fatigue, helped them accept their condition and feel psychological relief . Thus, yoga can also be used in patients with no chance of complete recovery whose physical performance status permits it. Moreover, yoga is a practice suitable not only for young people but also for older cancer patients . A study published in 2015 involving cancer patients over 60 years of age, numbering 97 in total, who had completed their treatments reported that yoga generally reduced side effects associated with cancer and cancer treatments.

Leading oncology institutions such as Memorial Sloan Kettering Cancer Center, the American Society of Clinical Oncology and Mayo Clinic also recommend yoga for cancer patients.

Is yoga a safe practice?

Since yoga techniques involve neither medication nor any intervention in the body, yoga is generally a very safe practice. Some adverse effects have been reported in the literature: venous thrombosis (blood clot formation in a vessel), embolism (a traveling clot), hematoma (blood collection under the skin), spontaneous pneumothorax and worsening glaucoma associated with prolonged immobility; and damage to nerves and joint ligaments from movements performed incorrectly. However, these occurrences are very rare. Certain postures and movements may be inadvisable during pregnancy, in certain circulatory diseases such as high blood pressure and heart failure, in some musculoskeletal diseases and in some cancer patients.

So what should be done?

Yoga is generally a safe practice that helps reduce cancer and cancer-related symptoms in cancer patients and improves quality of life. However, not every yoga technique is suitable for every patient. Some demanding techniques may pose serious risks for certain patients.

Therefore, cancer patients should:

• Always talk to their physicians before starting yoga classes and make sure that yoga is suitable for them.
• Ensure that the center providing their yoga classes is experienced, and ask how much experience it has with cancer patients.
• Obtain information about different types of yoga and avoid techniques involving excessively demanding postures and movements that are unsuitable for them.
• Know that yoga cannot be used alone to treat any health problem and that they must never interrupt the principal treatment for their disease.