Baseline Physical Activity Moderates the Effect of Yoga on Pain in Cancer Survivors

Abstract

PURPOSE: Greater than 50% of cancer patients experience pain, including neuropathic pain, arthralgia, and generalized pain, from cancer and its treatments. Pain often persists for years after treatment, significantly impairing recovery, physical function, and quality of life. We previously conducted a phase III randomized controlled trial (RCT) in cancer survivors showing that yoga ameliorates insomnia, fatigue, and impaired quality of life. To date, no phase III RCTs have examined both the influence of yoga on generalized pain and moderators to help understand for whom and when yoga works best. Here, we assessed 1) the effectiveness of yoga for treating pain and 2) factors that may moderate the influence of yoga on pain. METHODS: Cancer survivors (2-24 months post treatment, 96% female, 77% breast cancer) were randomized to either usual care (N=157) or Yoga for Cancer Survivors (YOCAS©®; N=167). YOCAS consists of breathing exercises, postures, and meditation in two 75-min sessions/wk for four wks. We assessed pain (0-10) using a Symptom Inventory both pre- and post-intervention. Potential moderators included: 1) Exercise Stage of Change (ESC; ESC question), 2) frequency of vigorous physical activity (Aerobics Center Longitudinal Study sweat question), 3) cancer stage (I-IV), 4) cancer treatment (surgery, chemotherapy, radiation, hormone therapy), and 5) age. RESULTS: Yoga reduced pain (change score; CS=-0.40, SE=0.18, p<0.01) whereas usual care did not (CS=-0.06, SE=0.18, p=0.38). Moderation analyses (p<0.01) demonstrated that 1) for survivors with frequent vigorous physical activity (>9/wk), pain decreased in yoga but increased in usual care; 2) for survivors with infrequent vigorous physical activity (<3/wk), pain did not change in either group. There was no evidence of moderation via ESC, age, cancer stage or treatment (ps > 0.11). CONCLUSION: Results suggest that yoga reduces pain in cancer survivors. Survivors with frequent vigorous physical activity (>9/wk) experiencing pain showed reduced pain by changing activity mode to yoga. In contrast, usual care survivors showed increased pain, and survivors with infrequent vigorous physical activity (<3/wk) showed no change in pain. Clinicians should consider yoga for survivors reporting pain. Funded by NCI via NCORP, R25, and K grants.