Randomized, controlled trial of yoga in women with breast cancer undergoing radiotherapy

Abstract

Purpose: Previous research incorporating yoga (YG) into radiotherapy (XRT) for women with breast cancer finds improved quality of life (QOL). However, shortcomings in this research limit the findings.

Patients and methods: Patients with stages 0 to III breast cancer were recruited before starting XRT and were randomly assigned to YG (n = 53) or stretching (ST; n = 56) three times a week for 6 weeks during XRT or waitlist (WL; n = 54) control. Self-report measures of QOL (Medical Outcomes Study 36-item short-form survey; primary outcomes), fatigue, depression, and sleep quality, and five saliva samples per day for 3 consecutive days were collected at baseline, end of treatment, and 1, 3, and 6 months later.

Results: The YG group had significantly greater increases in physical component scale scores compared with the WL group at 1 and 3 months after XRT (P = .01 and P = .01). At 1, 3, and 6 months, the YG group had greater increases in physical functioning compared with both ST and WL groups (P < .05), with ST and WL differences at only 3 months (P < .02). The group differences were similar for general health reports. By the end of XRT, the YG and ST groups also had a reduction in fatigue (P < .05). There were no group differences for mental health and sleep quality. Cortisol slope was steepest for the YG group compared with the ST and WL groups at the end (P = .023 and P = .008) and 1 month after XRT (P = .05 and P = .04).

Conclusion: YG improved QOL and physiological changes associated with XRT beyond the benefits of simple ST exercises, and these benefits appear to have long-term durability.

Fig 1.

Flow of study participants over study period.

Fig 2.

Change from baseline in Medical Outcomes Study 36-item short-form survey (SF-36) subscale scores. (A) SF-36 PCS change from baseline; (B) SF-36 physical function change from baseline; (C) SF-36 general health change from baseline. Significance values are from the MIXED models of change scores at each follow-up time point. (*) Yoga versus waitlist, P < .05. (†) Yoga versus stretch, P < .05. (‡) Stretch versus waitlist, P < .05.

Fig 3.

Change from baseline for fatigue. Significance values are from the MIXED models of change scores at each follow-up time point. (*) Yoga versus waitlist, P < .05. (†) Stretch versus waitlist, P < .05.

Fig 4.

Log-transformed cortisol level daily curves. (A) Daily log-cortisol mean at baseline. No group differences. (B) Daily log-cortisol mean at end of radiotherapy. Yoga has steeper slope than stretch and waitlist groups (P = .027 and P = .008, respectively). (C) Daily log-cortisol mean at 1 month. Yoga has steeper slope than waitlist (P = .05 and P = .04, respectively). Significance values are from the GLM analysis of cortisol slopes at each time point, covarying for baseline.