Guo-Qing Liu,Jing-Yi Han,Wen-Jing Song,Ying Wang

1Graduate School,Tianjin University of Traditional Chinese Medicine,Tianjin 301617,China.2Department of Critical Medicine,Tianjin First Central Hospital,Tianjin 300192,China.3Nursing Department,Tianjin First Central Hospital,Tianjin 300192,China.

Abstract The survival rate of cancer patients is rising,but the treatment of cancer will bring a series of physiological and psychological symptoms to patients,which will seriously affect the quality of life of patients.As a complementary and alternative therapy,yoga is more and more used in symptom management and quality of life improvement of cancer patients.This paper introduces the overview,implementation methods and application status of yoga,summarizes the application effect of yoga in the symptom management of cancer patients,analyzes the shortcomings in the application process at this stage,and puts forward the prospect,in order to provide a reference for the better application of yoga in the symptom management of cancer patients in the future.

Keywords:yoga;cancer;symptom management;review

Background

The incidence and mortality of cancer worldwide are increasing rapidly.The latest statistics of global cancer show that in 2018,there were about 18.1 million new cancer cases and 9.6 million deaths [1].With the continuous improvement of public health awareness,people are more and more aware of the importance of early detection,early diagnosis and early treatment of cancer.Coupled with the continuous development of medical technology,the cancer survival rate in China increased from 30.9% in 2003-2005 to 40.5% in 2012-2015 [2].At the same time,"healthy China 2030" proposes that the five-year survival rate of cancer in China should not be less than 43.3% in 2022 and 46.6% in 2030 [3].The survival rate of cancer patients is rising,but the treatment of cancer will bring a series of physiological and psychological symptoms to patients,which will seriously affect the quality of life of patients.Modern medical philosophy believes that the quality of life of cancer patients can better reflect the treatment status of patients than the survival rate,and it also has an important impact on the survival rate to a certain extent [4].Symptom management refers to providing care to patients to improve their quality of life and enable them to prevent or solve physical,psychological and social problems as soon as possible [5].Therefore,clinical medical staff should pay attention to the symptom management of cancer patients and improve their quality of life.Regular exercise has been shown to improve the health indicators of cancer patients.Such as improving cardiovascular health,muscle strength,fatigue,anxiety,depression,self-esteem,well-being,etc [6].Yoga is a kind of gentle exercise,and as a complementary and alternative therapy,it is more and more used in the symptom management and quality of life improvement of cancer patients.Research shows that [7-9],yoga can alleviate patients' bad emotions such as anxiety and depression,reduce fatigue symptoms,relieve pain,improve sleep quality and joint activity,increase strength and flexibility,and reduce the level of inflammatory factors.This paper summarizes the overview,practical application and application status of yoga in symptom management of cancer patients,in order to provide a reference for clinical nursing.

Overview of yoga

The word yoga originates from Sanskrit "yuj",which means"integration and connection." In the traditional sense,yoga is a philosophy.It conveys a method to solve the problems of body,mind and spirit,so as to transfer people's senses from the material level to the internal level of thought,so as to achieve physical and mental health [10].In the modern sense,yoga is a new gentle sport that emphasizes the combination of body,mind and breath.Traditional classical yoga mainly includes hatha yoga,Ashtanga Yoga(King yoga,eight branch yoga),wisdom yoga,karma yoga,faith yoga and mandala yoga,of which Hatha Yoga is the most widely used [11].In the modern development process of yoga,the functional and targeted yoga practice methods continuously launched according to the needs of the audience are mostly based on the evolution of Hatha Yoga[12].For example,according to the differentiated needs of people's characteristics,there are targeted yoga practice methods such as pregnant women's yoga,parent-child yoga,elderly yoga,strength yoga (for men),Iyengar assisted yoga (for the practice of body recovery after injury),office yoga and so on,which meet the needs of different people [13].

Specific implementation methods of yoga

At present,there is no unified operation guide and recognized standardized implementation process for yoga therapy,which generally includes the following three parts: (1) Asana: dredge the meridians of the whole body,exercise muscle strength and optimize the body curve through different postural movements;(2) Breath regulation: massage internal organs,regulate endocrine and improve the detoxification function of lymphatic system through the unique chest and abdomen breathing method;(3) Meditation: relax nerves,relieve fatigue,improve sleep and achieve the unity of body and mind through rest and voice meditation [12,14].

Yoga intervention generally lasts for 8-12 weeks,1-2 times a week,60-120 minutes each time.Professional yoga coaches provide on-site guidance,and encourage patients to practice at home,guided by professional video records.

The application of yoga in clinic

In recent years,yoga has been more and more used in the research of clinical treatment and rehabilitation.Yoga plays a role through the psychological and neuroimmune mechanisms,which can significantly reduce the level of inflammatory factors in patients with rheumatoid arthritis and alleviate the symptoms of depression[15].Wu et al.[16]showed that yoga can reduce the systolic and diastolic blood pressure of patients with hypertension by 11 and 6 mmHg respectively.Yoga intervention can also reduce BMI (body mass index),blood sugar,glycosylated hemoglobin,blood lipids,IL6 (interleukin-6) and TNF-ɑ(tumor necrosis factor- ɑ ) in diabetic patients [17].In terms of respiratory diseases (such as chronic obstructive pulmonary disease,asthma,etc.),yoga can improve patients' exercise tolerance,improve sleep quality,and have a positive impact on respiratory function and symptom control [18,19].In terms of nervous system diseases (such as Parkinson's disease,multiple sclerosis,etc.),yoga intervention can reduce the risk of falls,improve the patient's posture stability and functional and frozen gait,increase muscle strength and alleviate negative emotions [20,21].In addition,yoga has also significantly improved the audio-visual response and neurogenic bladder dysfunction and bladder symptoms of patients with chronic multiple sclerosis[22].

Effect of yoga in symptom management of cancer patients

Relieve negative emotions

The mental health problems of cancer patients are becoming more and more prominent.The diagnosis and treatment of the disease will bring a huge psychological burden to patients,and it is very easy to produce negative emotions such as anxiety and depression.Yoga can stimulate the better coordination and unity of body and spirit through specific postures,relaxation between postures,breathing skills,meditation and visualization,so as to combat the negative emotions during chemotherapy.A meta-analysis by Gonzalez et al.[23] evaluated the impact of yoga based intervention on self-reported depression and anxiety symptoms of cancer patients.The results showed that yoga is a promising treatment,and yoga based intervention is related to the improvement of depression and anxiety symptoms of cancer patients.Lanctot et al.[24] conducted a randomized controlled trial of 101 breast cancer patients undergoing chemotherapy.The intervention group participated in an 8-week yoga program on Bali Island for 90 minutes.The control group received routine nursing.After 8 weeks,the yoga group was given yoga treatment.The results showed that the depression score of the control group increased significantly,while the intervention group did not change.In the sixteenth week,the repeated measures analysis in the control group showed that after receiving the Bali Island yoga program,the depression score increased.Depressive symptoms improved significantly.Although the depressive symptoms were not significantly reduced after the intervention,yoga treatment played a protective role and prevented the deterioration of depressive symptoms.It emphasized the importance of rapid intervention during chemotherapy to reduce symptoms.Hardoerfer et al.[25]conducted a randomized controlled trial on 70 patients with different types of cancer.The intervention group received yoga therapy for 8 weeks,once a week,60 minutes each time.The control group received yoga therapy only after the intervention.The results showed that compared with the control group,the anxiety score of the intervention group was significantly reduced,but it had no significant effect on the improvement of depression.This may be related to the evaluation method.The Patient Health Questionnaire-2(PHQ-2)used to evaluate depressive symptoms in this study has only two items,which may lack sufficient sensitivity.Lundt et al.[26] based on the randomized controlled trial of Hardoerfer et al.,followed up the patients to assess the long-term changes of anxiety and depression symptoms 6 months after the end of yoga treatment.The results showed that compared with before treatment,the symptoms of anxiety and depression were significantly reduced 6 months after yoga intervention.However,during the follow-up period from the end of yoga treatment to 6 months later,anxiety symptoms increased slightly,but there was no significant difference,while depression symptoms remained stable.This study shows that yoga has positive significance for the long-term improvement of anxiety and depression.However,this study is an observational study with relatively low reliability,which should be confirmed by randomized controlled trials.

Relieve cancer-related fatigue

Cancer-related fatigue (CRF) is a kind of physical,emotional and cognitive fatigue or fatigue related to cancer or cancer treatment.Its incidence is 25%-99%.It is the most common symptom in cancer treatment [27].Different from the fatigue of healthy people,cancer-related fatigue cannot be relieved by rest [28].If it is not treated in time,it will continue to perplex cancer patients and reduce their quality of life.Drug intervention has certain side effects,so most of them use non-drug intervention,such as sleep therapy,cognitive behavioral therapy,psychological intervention,acupuncture treatment,to alleviate the fatigue symptoms of cancer patients [29].As a low-intensity exercise,yoga has high safety,and is suitable for independent family exercise.It has strong feasibility for patients.Vadiraja et al.[30] conducted a randomized controlled trial of 91 patients with advanced breast cancer.The intervention group received yoga therapy for 3 months.The control group received supportive treatment and health education.The results showed that compared with the control group,the fatigue severity,fatigue frequency and fatigue diurnal changes of the intervention group were significantly reduced.Zetzl et al.[31]randomly divided 173 patients with different types of cancer suffering from mild to severe fatigue into intervention group and control group.The intervention group received yoga intervention once a week,60 min once,for a total of 8 weeks.The control group did not receive any special treatment.The results showed that the overall fatigue and physical fatigue scores of the intervention group were significantly lower than those of the control group.The study also found that compared with other female cancer patients,yoga has a better effect on relieving fatigue in women with breast cancer.Yoga can help patients enter a state of natural relaxation,release pressure,and have a good regulatory effect on brain and body functions,so as to reduce the fatigue of patients.

Relieve pain symptoms

Pain is a subjective symptom,which is an unpleasant feeling and emotional experience related to the actual or potential tissue injury of the body [32].The survey report shows that 90% of cancer patients have experienced pain in a certain period of illness [33].Pain will limit patients' activities,have a negative impact on physical and psychological functions,and then affect patients' rehabilitation and later quality of life.Carson et al.[34] conducted an 8-week randomized controlled trial in 48 patients with breast cancer.The intervention group received yoga therapy once a week,120 min/time,under the guidance of professional yoga instructor.The control group was provided with supportive treatment by professional therapists.The results showed a dose/response relationship between yoga practice duration and daily pain in the intervention group,with patients more likely to experience lower pain the next day when they spent relatively more time practicing yoga for two consecutive days.Eyigor et al.[35] adopted a prospective randomized controlled study to analyze the effects of Hatha yoga training on pain symptoms on shoulder and arm pain symptoms in breast cancer patients.The intervention group received yoga training for 10 weeks,2 times/week,1 h/time,and the control group received routine nursing and follow-up.The results showed that the pain severity of the intervention group improved significantly,and the follow-up results showed that the curative effect remained unchanged for 2.5 months after the intervention.The study evaluated the efficacy of yoga.Yoga is a safe and effective exercise,and as a medical complementary alternative therapy,it can make patients have a relaxation response,relieve patients' pain and improve patients'quality of life.

Improve range of motion and strength of joints

A series of treatment processes such as surgery,radiotherapy and chemotherapy may lead to many complications such as lymphedema and peripheral neuropathy,manifested in varying degrees of sensory and motor dysfunction,resulting in the limitation or even loss of joint range of motion and strength,which seriously affects the quality of life of patients [36,37].Mazor et al.[7] took a gradual,safe and gentle yoga posture with emphasis on upper body strength and flexibility.21 patients with breast cancer undergo 8 weeks of yoga training.After the intervention,the results showed that the joint range of motion of bilateral shoulder flexion and external rotation increased significantly,the abduction range of the healthy side improved significantly,and the abduction,grip strength and bilateral elbow flexion strength of the affected side improved.Loudon et al.[36]conducted an 8-week randomized controlled trial in 23 patients with breast cancer.The intervention group received 90 minutes of yoga training and 45 minutes of autonomous yoga every day.The control group received routine nursing.The results showed that the pelvic posture and pelvic inclination of the intervention group improved compared with the control group,and the strength of the shoulder and abduction of the affected limbs and healthy limbs increased significantly.However,there was no significant difference in the improvement of shoulder range of motion between the two groups,which may be related to the focus of yoga intervention in this study on body posture and movement mode rather than increasing movement flexibility.Yoga is a feasible and beneficial exercise plan.Yoga practice is beneficial to lymphatic circulation.External forces are generated by nearby muscle extension or contraction,arterial pulsation and respiratory movement.Through the combination of pressurization and negative pressure,it can change lymphatic flow[7]and reduce edema,so as to improve shoulder joint mobility to a certain extent,increase limb resistance and flexibility,and help improve the physical function of cancer patients.

Improve sleep quality

Cancer patients are often accompanied by sleep disorders due to pathological and psychological factors.Studies [38] have shown that patients with different conditions,such as early sleep,sleep deprivation and other negative symptoms,usually have more than 50% of patients with cancer.Yoga can help patients eliminate mental tension,relieve pressure,stabilize mood,help the body in the right position,stretch,relax and strengthen muscles,alleviate physiological pain,stimulate the normal secretion of hormones by glands,improve brain function and overall body function,and then improve sleep quality [39].Lin et al.[38] conducted a multicenter randomized controlled trial on 410 patients with different types of cancer.The intervention group received yoga training for 4 weeks,2 times/week and 75 min/time on the basis of routine nursing,and the control group was given routine nursing.The results showed that compared with the control group,the intervention group had significant improvement in overall sleep quality,subjective sleep quality and daytime dysfunction after intervention.In addition,the intervention group also showed a decrease in the use of sleep drugs.Chaoul et al.[40] randomly divided the patients with stage I to III breast cancer of the American Joint Committee on Cancer into Tibetan yoga group,stretching project and routine nursing group.During chemotherapy,the Tibetan yoga group and the stretching project group participated in four training courses for 75-90 minutes each time,and the patients were encouraged to practice at home.During the follow-up period,they received three intensive treatments,which were evaluated at baseline,1 week,3 months,6 months and 12 months after treatment.The results showed that compared with the other two groups,the Tibetan yoga group reported less daily sleep disorders after 1 week of treatment,and no difference was found in the total sleep disorders between the two groups.However,during the follow-up period,patients in the Tibetan yoga group who practiced at least twice a week showed better sleep effects at 3 and 6 months after treatment compared with patients who did not practice yoga.The reason why the effect of Tibetan yoga is not obvious in this study may be related to the teaching frequency and teaching time.

Other effects

Inflammatory factors are closely related to a variety of adverse prognosis such as cancer cell metastasis and cancer recurrence,and are often used as auxiliary indicators for treatment effect and prognosis evaluation [41].Huberty et al.[42] showed that online yoga intervention for patients with myeloproliferative tumors for 12 weeks and 60 minutes a week in the form of teaching video can reduce TNF-ɑ,and confirmed the feasibility of remote collection of blood samples from patients nationwide.However,the sample size of this study is small,and it is not compared with the control group.The conclusion needs to be confirmed by further research.Nausea and vomiting is a common adverse reaction during chemotherapy,which will have adverse effects on the physiology and psychology of patients.Jong et al.[43] conducted a multicenter randomized controlled trial of 83 breast cancer patients undergoing chemotherapy.The intervention group received 12 weeks,1 times/week,75 min/yoga courses on the basis of routine nursing,while the control group only received routine nursing.At baseline,3 months and 6 months,the intervention group was evaluated.The results showed that in 6 months,the nausea and vomiting symptoms of the yoga group improved significantly compared with the control group.And the proportion of people returning to work is high.However,due to the lack of data on the working status of some patients,the results of this study must be interpreted carefully,and the potential benefits of yoga on occupational rehabilitation can be further studied.

Conclusion

Yoga has relatively high safety and relatively low cost.It can effectively manage patients with negative emotions,cancer-related fatigue,pain,lymphedema and sleep disorders and other symptoms,so as to improve the quality of life of cancer patients.However,there are still some limitations.At present,there are relatively few studies in China.Most of the existing studies abroad have small sample size and few study types of patients (mainly breast cancer).The form of intervention is relatively simple,and there is no uniform operation guide and accepted standardized implementation process.Future research can expand the sample size to further verify the intervention effect of yoga in cancer patients;Include more patients with different types of cancer to increase the universality of research results;The intervention form of online yoga can be adopted.Patients can flexibly choose the practice time according to their personal situation,but the problem of low compliance of patients due to unsupervised needs to be considered;Summarize the best evidence,formulate unified operation guidelines and recognized standardized implementation processes.Therefore,the majority of medical workers still need to constantly explore and improve the clinical application of yoga therapy in the future,so as to provide a more scientific basis for the symptom management of cancer patients.