There is evidence showing that yoga therapy improves multiple aspects of QOL, including physical functioning, emotional health outcomes, and the symptoms cancer patients may experience, such as sleep disturbances, fatigue, and pain. Danhauer et al systematically reviewed both nonrandomized trials and randomized controlled trials involving yoga during cancer treatment.50 They found that yoga improved depression and anxiety as well as sleep and fatigue. Benefits of yoga in cancer based on randomized controlled trials are summarized in the Table. The role of yoga in improving QOL and managing symptoms patients experience during and after treatment is discussed in the following sections.
Quality of Life
Danhauer et al’s systematic review of trials involving yoga during cancer treatment found that yoga improved multiple aspects of QOL.50 For example, yoga has been shown to improve QOL in breast cancer patients undergoing radiotherapy. In a study by Chandwani et al, yoga (60-minute sessions twice a week for 6 weeks) was associated with better general health perception and physical functioning scores as well as greater benefit finding, or finding meaning in their experience, after radiotherapy compared with a wait-list group.51 The yoga group had an increase in intrusive thoughts, believed to be due to a more thorough processing of the cancer experience, which helps to improve patients’ outlook on life.52 The benefits of yoga extend beyond psychological measures during radiation treatment. Yoga was found to increase physical functioning compared with stretching in breast cancer patients undergoing radiotherapy.53
Cognitive Function
Cancer-related cognitive impairment commonly occurs during cancer treatments (eg, chemotherapy, radiotherapy, surgery, hormone therapy) and persists for months or years in survivors.54 Impairment of memory, executive function, attention, and concentration are commonly reported. In a trial of a combined hatha and restorative yoga program called Yoga for Cancer Survivors (YOCAS), which was designed by researchers at the University of Rochester, patients in the yoga arm had less memory difficulty than did patients in the standard care arm.55 However, the primary aim of the trial was to treat insomnia, so this secondary outcome needs to be interpreted with caution. Deficits in attention, memory, and executive function are often seen in cancer-related cognitive impairment, and the meditative aspect of yoga may have behavioral and neurophysical benefits that could improve cognitive functions.56 More evidence is needed to understand the role of yoga in improving cognitive functioning.
Emotional Health
Psychosocial stress is high among breast cancer patients and survivors.57,58 This causes circadian rhythm and cortisol regulation abnormalities, which are reported in women with breast cancer.59-64 Yoga is known to help stress and psychosocial and physical functioning in patients with cancer.65 Yoga was also shown to be equivalent to cognitive behavioral therapy in stress management in a population of patients without cancer.66 Daily yoga sessions lasting 60 minutes were shown to reduce reactive anxiety and trait anxiety in early-stage breast cancer patients undergoing conventional radiotherapy and chemotherapy compared with patients receiving supportive therapy, highlighting the role of yoga in managing anxiety related to treatment.67 In a study done by Culos-Reed et al, 20 cancer survivors who did 75 minutes of yoga per week for 7 weeks were compared with 18 cancer survivors who served as a control group.68 The intervention group reported significant improvement in emotional well-being, depression, concentration, and mood disturbances. In a longitudinal study by Mackenzie et al, 66 cancer survivors completed a 7-week yoga program and were assessed at baseline, immediately after the final yoga session, and at 3 and 6 months after the final session.69 Participants had significantly improved energy levels and affect. They also had moderate improvement in mindfulness and a moderate decrease in stress. Breast cancer patients who underwent restorative yoga sessions found improvements in mental health, depression, positive affect, and spirituality (peace/meaning).70 This was more pronounced in women with higher negative affect and lower emotional well-being at baseline. In a study of patients with ovarian cancer receiving chemotherapy, patients were instructed to perform up to 15-minute sessions including awareness, body movement, and breathing.71 Even with just 1 session of yoga intervention, patients experienced decreased anxiety.
Fatigue
Studies on yoga show improvement in fatigue both during and after treatment. In breast cancer patients undergoing chemotherapy, yoga was shown to benefit cognitive fatigue.72 Older cancer survivors also seem to benefit from yoga interventions.73 In a trial of a DVD-based yoga program, the benefits of yoga were similar to those of strengthening exercises, and both interventions helped decrease fatigue and improve QOL during the first year after diagnosis in early-stage breast cancer patients with cancer-related fatigue.74 Bower et al also showed that, for breast cancer survivors experiencing persistent chronic fatigue, a targeted yoga intervention led to significant improvements in fatigue and vigor over a 3-month follow-up compared with controls.75 Fatigue is commonly seen in breast cancer patients who are receiving adjuvant chemotherapy. In a study by Taso et al, women with breast cancer receiving chemotherapy were assigned to 60-minute yoga sessions incorporating Anusara yoga, gentle stretching, and relaxation twice a week for 8 weeks.76 By week 4, patients with low pretest fatigue in the yoga group experienced a reduction in fatigue. By week 8, all patients in the yoga group experienced a reduction in fatigue. Four weeks after the yoga intervention, patients in the group maintained the reduction in fatigue. This study shows the feasibility of an 8-week yoga program for women undergoing breast cancer therapy by improving fatigue. Yoga recently was added to National Comprehensive Cancer Network (NCCN) guidelines for management of cancer-related fatigue (level 1 evidence).77 However, the evidence was based on studies in women with breast cancer and survivors; therefore, more studies are needed in men and women with other cancers.
