By German H. Rodriguez, MD
Attending Physician, West Park Medical Group, New York, NY
Dr. Rodriguez reports no financial relationships relevant to this field of study.
SYNOPSIS: Breast cancer survivors participating in a 12-week yoga program reported decreased fatigue, increased vitality, and improved sleep on multiple scoring systems, but no impact on depressive symptoms. Increased time spent doing yoga led to greater improvements in inflammation, mood, and fatigue.
SOURCE: Kiecolt-Glaser JK, et al. Yoga’s impact on inflammation, mood, and fatigue in breast cancer survivors: A randomized controlled trial. J Clin Oncol. 2014;32:1040-1049.
In 2010, an estimated 2,829,041 women were living with breast cancer in the United States. Breast cancer affects women of many different age groups. Due to widespread implementation of breast cancer screening, a majority of these are diagnosed at a very early stage. According to the National Cancer Institute, the 5-year survival for localized breast cancer is 98.6%.1 Cancer patients tend to have lower exercise tolerance and depressed mood. Many factors could be implicated in this common scenario, but the more relevant question lies in what we can do to help these patients continue to lead full lives. Kiecolt-Glaser et al proposed a regimen of supervised yoga as a way to improve mood and decrease fatigue in patients with breast cancer.2
The study investigators designed a randomized, controlled trial in which a 12-week Hatha yoga intervention was compared to a wait-list control group. Two hundred stage 0 to IIIA female breast cancer survivors ranging from age 27 to 76 years were recruited. All participants had completed cancer treatments within the past three years, and it had been at least three months since surgery, adjuvant therapy, or radiation. Any patient with a prior history of breast cancer, other types of cancer (except skin cancer), anemia, diabetes, chronic obstructive pulmonary disease, uncontrolled hypertension, evidence of liver or kidney failure, symptomatic ischemic heart disease, autoimmune or inflammatory diseases, cognitive impairment, and alcohol/drug abuse were excluded. Patients who reported > 5 hours of vigorous exercise or who had practiced yoga within the past 6 months also were excluded.
Each patient was stratified based on her cancer stage as well as whether she had received radiation therapy. Afterward, the participants were randomly assigned to either the yoga group or the control group. The data manager did not have any patient contact, and patients were asked not to mention their group to any study personnel. The lab technicians were blind to all data.
All study participants underwent assessments at baseline, immediately post-treatment, and 3 months post-treatment. At each visit, fasting blood samples were obtained to measure interleukin-6, interleukin-1B, and tumor necrosis factor alpha. Multiple well-validated questionnaires evaluated other important quality-of-life measures: degree of fatigue in the last week (MFSI-SF), vitality over the last month (SF-36), depressive symptoms in the last week (CES-D), sleep quality over the last month (PSQI), perceived support (ISEL), frequency and duration of various physical activities (CHAMPS), and foods and beverages consumed in the past 90 days.
The women who were assigned to the Hatha yoga intervention group participated in two 90-minute sessions per week. Twenty-four specific poses were included in the study protocol. A senior Hatha yoga instructor conducted the initial group to improve adherence to the specific poses. The video of this initial session was used to train the six other instructors. All instructors were certified by the Yoga Alliance.
Baseline demographic characteristics were very similar in the two groups. They also reported similar degrees of physical activity and feelings of fatigue at baseline. Of the original 200 participants, 186 completed the study: 96 in the yoga group and 90 in the control group. There was no baseline difference of the study outcomes in the two groups. The intervention group attended a median of 19 of 24 possible classes, with an average of 24.69 minutes of yoga per day during the 12-week study period.
Intervention Effects on Fatigue, Vitality, and Depressive Symptoms
There was no difference between the two groups at the immediate post-treatment visit (6.1 vs. 10.3; p = 0.058), but mean fatigue was significantly lower in the yoga group at the 3-month post-treatment visit (5.4 vs. 12.4; p = 0.002).
The average vitality score was higher in the yoga group at the immediate post-treatment visit (58.7 vs 51.6; p = 0.01) and at the 3-month post-treatment visit (58.1 vs 51.6; p = 0.01).
Depressive symptoms were not significantly different at either the immediate post-treatment visit or the 3-month post-treatment visit.
Intervention Effects on Inflammation
There was no significant difference between groups at the baseline visit or the immediate post-treatment visit of all three measured cytokines. At 3 months, the yoga intervention group had significantly decreased cytokine levels compared with the control group. Mean values of TNF-a decreased by 13% (p = 0.027), IL-6 decreased by 16% (p = 0.027), and IL-1 decreased by 20% (p = 0.037). Secondary analysis showed that the frequency of yoga practice had a significant impact on cytokine levels. At 3 months post-treatment, a 10-minute per day increase in yoga practice was associated with a 5% decrease of IL-6 (p = 0.01) and an 8% decrease of IL-1B (p = 0.03).
Health, Behavior, and Support
There was no change in the two groups in diet, body mass index, weight, or social support throughout the study. The yoga group patients did report a significant improvement in sleep quality and decreased sleep disturbance (p = 0.03).
Yoga’s popularity has increased dramatically in the past 10 years. By some estimates, there were 4 million Americans practicing yoga in 2004, which increased sharply to about 20 million as of 2011.3 According to the National Center for Complementary and Alternative Medicine, yoga is the sixth most commonly used alternative therapy in the United States.4 The potential benefits of yoga have been studied for a multitude of reasons, including depression, pain, and several quality-of-life measures in cancer patients.
This study effectively investigated the impact of a yoga intervention in patients with breast cancer and compared it to a similar group who did not practice yoga. They evaluated multiple well-validated measures of quality of life and three inflammatory markers. There was a significant reduction in levels of fatigue and inflammatory markers and an increase of vitality in the yoga intervention group. Also, these patients reported improved quality of sleep. There was no impact on depressive symptoms.
Subclinical inflammation has been proposed as a risk factor for developing chronic disease and disability among older adults.5 In addition, studies have shown that cancer survivors have a greater risk of developing secondary cancers and other chronic diseases such as diabetes, cardiovascular disease, and osteoporosis.6 Chronic inflammation has been proposed as an integral component in the development of fatigue and subsequent declines in physical function.7
It is unclear if we should recommend yoga for depressive symptoms. The results of this study did not show any impact on depressive symptoms. There have been multiple studies evaluating the impact of yoga on depressive symptoms. Overall, the findings have been inconclusive, as some studies have found a significant positive impact and others have failed to emulate these results. Many of the studies that have shown that yoga may have a positive impact on depressive symptoms have involved small samples with mixed methodological quality.8,9
So what’s the bottom line? Should we recommend yoga to our breast cancer patients as an adjuvant therapy? Can these results be extrapolated to other patient populations with other types of cancers or other chronic diseases?
We should encourage yoga practice as an adjuvant therapy to our patients with a few caveats. Some of our patients with chronic conditions may not have the habit of practicing any form of physical activity. We should advise patients to join classes that will provide them with graded exercises that are appropriate for their level of conditioning and degree of flexibility to avoid potential injuries. This is especially important in patients who have bony metastasis, as they have a higher risk of pathologic fractures. Many patients may be apprehensive to start practicing yoga if they have not been physically active for a prolonged period. Some studies have found yoga to be superior to other forms of conventional physical activity.8 Regardles of their health status, it is important for all yoga participants to be conscious of their own bodies’ abilities and restrictions to ensure that they practice safely. When practiced appropriately, yoga can be very well tolerated. Patients should be aware of their individual skill levels to avoid the risks of overstretching, strains, fractures, overheating, dehydration, and decreased blood glucose levels.10
The patients included in this study did not practice any form of habitual exercise. It remains to be seen if patients who are frequently physically active and have a diagnosis of breast cancer will also have lower rates of inflammation and improved quality-of-life measures when compared to their more sedentary counterparts.
It has been postulated that yoga enhances health via multiple mechanisms, including increased endorphin release, decreased sympathetic tone, increased parasympathetic tone, and increased melatonin.11
All patients included in this study had undergone some form of conventional therapy. Whether yoga has a similar impact on patients who have opted not to undergo some form of conventional therapy is unknown.
A recent study by Chandwani et al examined the impact of a 6-week yoga program in patients who were undergoing radiation therapy.12 The study also showed decreased levels of fatigue in the yoga intervention group. Instead of measuring inflammatory markers, they measured cortisol levels. The yoga intervention group had significantly decreased cortisol levels. This could represent an alternate mechanism through which yoga has beneficial effects on breast cancer patients. Patients who had other comorbidities were excluded from the study.
We should discuss the importance of managing some of the conditions that frequently accompany cancer and its treatment prior to promoting the potential benefits of yoga.
The study sample was small and, even though the results were positive, the impact of yoga should still be evaluated in larger population-based clinical trials. Due to the multitude of cancers that are commonly diagnosed in the United States, we cannot say for certain that yoga will have similar benefits in any other type of cancer, but if the patients are chosen carefully and advised appropriately, yoga could be an important part of how we manage cancer in the future.
It is unclear why there was no impact on depressive symptoms, as other studies have shown a positive impact on depressive symptoms. This potentially could be related to the small sample size. Fatigue and depression symptoms were not used as part of the inclusion criteria, so women who were less fatigued and less depressed had less room to show positive changes. Previous studies have found that yoga increases serotonin levels.11 This could be a potential mechanism by which yoga impacts depressive symptoms.
Lastly, we do not know how long the positive results of this study will continue to bestow benefits on patients. Subsequent studies should consider evaluating the long-term impact of yoga on survival and other important outcomes. This trial showed that yoga had a positive impact on inflammation, fatigue, sleep, and vitality in the evaluated study participants in a dose-dependent fashion. Yoga is a simple intervention that we should have in our repository when we guide our patients through the struggles brought on by breast cancer and other forms of chronic disease.