Yoga might benefit breast cancer victims
SAN ANTONIO, TX - Patients with metastatic breast cancer might benefit from the practice of yoga, according to a new study presented at the 34th Annual San Antonio Breast Cancer Symposium (San Antonio, TX; December 6-10, 2011. A small randomized trial was collaboratively conducted by yogis and physicians, including S.K. Gopinath, MD, from the Department of Surgical, Medical and Radiation Oncology at the HCG-BIO Super Specialty Center in Bangalore, Karnataka, India. The researchers found that yoga might reduce psychological distress and modulate abnormal cortisol levels as well as immune responses in patients with metastatic breast cancer.
The randomized study was comprised of 45 women who underwent a daily yoga intervention and 46 who received standard supportive counseling. The subjects, with an average age of 50.5 years, were assessed at baseline and three months after the intervention.
The researchers found that the yoga intervention was markedly effective in improving psychosocial states. Following the study period, a statistically significant decrease was found in in anxiety, depression, perceived stress, fatigue severity, and fatigue interference in the yoga group, compared with the control group. Furthermore, the yoga group had a significant improvement in emotional function, role function, cognitive function, and global quality of life.
The investigators also evaluated biologic measures. At the beginning and the end of the intervention, daily saliva samples were collected at 9:00 a.m. and 10:00 p.m., and enzyme immune assay kits (Salimetrics) were used to evaluate cortisol levels. In addition, blood samples were collected for three consecutive days between 8:00 a.m. and 10:00 a.m. in order to enumerate the number of natural killer cells with flow cytometry. (Cytometry is a procedure that counts and examines microscopic particles, such as cells and chromosomes, by suspending them in a stream of fluid and passing them by an electronic detection apparatus.) Yoga was found to be of value in reducing cortisol levels.
A significant difference was found in the early morning (6:00 a.m.) cortisol levels. This finding means that cortisol, which is a measure of stress and naturally decreases when the body is at rest, was successfully modulated in the yoga group. Research has shown that patients with metastatic breast cancer whose diurnal (twice-daily) cortisol rhythms were flattened or abnormal have earlier mortality.
After the intervention, a significant increase in the percentage of natural killer cells was found in the yoga group, compared with the control group. Previous research has demonstrated that natural killer cells, which are naturally occurring cytotoxins (cell-killers), play a therapeutic role in the treatment of human cancers.
The study authors concluded that, in view of the foregoing laboratory values, yoga might improve overall quality of life in patients with metastatic breast cancer.
Psychosocial factors are much more difficult to quantify, compared to laboratory values such as cortisol levels. In order to define psychosocial outcomes, the researchers used a variety of common instruments to measure them: mood states (a hospital anxiety and depression scale), sleep quality (the Pittsburgh Insomnia Rating Scale), quality of life (the EORTC Core Quality of Life Questionnaire for breast cancer [QLQ-C30]), and perceived stress (a perceived stress scale). Data were analyzed using both parametric (analysis of covariance, with a respective baseline measure as a covariate) and nonparametric (the Mann–Whitney U test) tests to evaluate the effects of intervention on the outcome measures. In addition, data for salivary cortisol were log transformed, and area under the curve and cortisol slope were computed using a linear mixed-effects model.
The researcher noted that the cancer patients were most likely under great duress. They wrote: “Metastatic breast cancer patients experience tremendous psychological distress due to treatment, disease, and uncertainty of their survival.”
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