The Effect of Stress on Breast Cancer Prognosis
Psychological distress associated with a diagnosis of breast cancer can evoke an array of emotional experiences, ranging from sadness and despair to anxiety and depression. The shock associated with initial diagnosis, through arduous treatment regimens and ongoing fear of recurrence, can have significant effects on psychological wellbeing. Although emotional symptoms may dissipate, an appreciable number of survivors continue to experience anxiety and depression for years after diagnosis. Psychological stress may elicit a number of physiological changes, including: endocrine responses, which can increase angiogenesis, cell proliferation and migration; disruptions in circadian rhythms and secretion of stress-related hormones such as glucocorticoids and catecholamines; and immune function, resulting in decreased natural killer cell and cytotoxic T-cell activity and increased levels of circulating inflammatory cytokines. Over time, these physiological responses to stress may increase the risk of chronic disease and influence breast cancer mortality.
Epidemiological research suggests that chronic stress due to depression, psychological distress and lack of social support may be a risk factor for breast cancer development and progression. For example, breast cancer survivors who suffered stressful life events, such as divorce, or death of a husband or child, had a significantly higher risk of relapse compared with survivors without such stressors. Women with strong social ties to relatives, friends and neighbors had significantly lower risk of breast cancer mortality compared with women lacking a social network. Similarly, in 2835 women diagnosed with breast cancer, those who felt socially isolated (no close relationships with friends, relatives or adult children) before diagnosis had a 66% increased risk of all-cause mortality and a twofold increase in breast cancer mortality. A meta-analysis indicated that psychosocial stress has an adverse effect on cancer incidence and survival – stressful life experiences were associated with higher cancer incidence, poorer survival and higher cancer mortality.
Stress Reduction & QoL in Breast Cancer Survivors
Group Support In addition to the effects of stress on breast cancer prognosis, a number of studies have examined the impact of stress on QoL in breast cancer survivors. Breast cancer patients often experience social isolation during months of treatment and recovery, which precipitate feelings of loneliness, low self esteem and body image issues, and negatively impact their QoL. Two types of group support have been evaluated for their ability to improve QoL: cognitive behavioral therapy, which uses conversation and active participation to resolve dysfunctional emotions and behaviors in individual or group settings; and psychoeducational therapy, which provides cancer education to patients, teaches coping mechanisms, and offers support and resources to improve psychosocial functioning. Several meta-analyses suggest that these interventions have a positive effect on cancer patients for certain symptoms such as distress, depression, anxiety, fatigue and QoL,[91–94] while other studies conclude that psychosocial interventions are ineffective or limited in producing meaningful emotional benefit.[95–97]
Many studies evaluating the effects of group support in breast cancer patients evaluated the effects of therapy in relatively small numbers of women with wide variability in levels of stress, anxiety and depression at baseline, which may mask the effects of group support in women with high emotional distress. Despite the inconclusive nature of current research, psychosocial interventions are rapidly becoming an important component of cancer care. For healthcare professionals to provide evidence-based guidance to their cancer patients, high-quality well-controlled trials with predefined outcome measures are needed to determine the precise benefits of psychosocial interventions.
Yoga Yoga is a mind–body therapy that originated in India more than 5000 years ago to reduce stress and promote overall physical and mental wellbeing. The practice of yoga relies on physical postures, focused breathing and meditation to stretch muscles, control breathing and minimize stress through visualization techniques and guided imagery. Cancer survivors, in particular, tend to use CAM approaches such as yoga to alleviate common symptoms including fatigue, pain and insomnia, which may persist long after treatment has been completed.[100–102]
Initial scientific research suggests that yoga may confer a variety of psychological and physical health benefits to breast cancer patients. Small randomized trials have observed significant reductions in fatigue severity, as well as improved vigor and emotional wellbeing following 8–12-week Iyengar yoga interventions.[103,104] A recent meta-analysis of ten studies found that cancer patients participating in yoga showed significantly greater improvements in psychological health, including anxiety, depression, distress and stress, compared with waitlist controls or supportive therapy groups. Breast cancer survivors can improve psychosocial functioning through yoga while they are undergoing active clinical treatment and for years following diagnosis.
Chronic pain and other sequelae such as paraesthesia (burning or tingling sensation of the skin), allodynia (pain caused by light touch) and lymphedema are significantly more frequent in breast cancer survivors compared with women in the general population.[108–110] Yoga has been shown to alleviate various forms of chronic pain experienced by many breast cancer survivors, including lower back pain, pain associated with fibromyalgia and rheumatoid arthritis.
Chronic stress is a common ailment that can negatively impact QoL and survival in women with breast cancer. As an increasing number of women turn to CAM to improve their health after breast cancer diagnosis, it is critical to develop effective methods for managing stress. To date, group support has shown mixed overall results in patients suffering from anxiety and depression, but seems to improve survival in patients with the highest levels of anxiety and depression. Yoga has shown promising results in relieving psychological distress and decreasing fatigue, and may be effective in treating chronic pain associated with side effects of treatment. Most studies to date have been too small to adequately define treatment effects; therefore large-scale studies are urgently needed to quantify the potential benefits of group support, yoga and other measures of stress reduction in breast cancer patients.
Expert Rev Pharmacoeconomics Outcomes Res. 2012;12(4):451-464. © 2012 Expert Reviews Ltd.