Stressful Events May Increase Breast Cancer Recurrence Risk

ROCHESTER, NY, Sept 27-Breast cancer patients with a history of traumatic or stressful life events have a 2-fold increased risk of recurrence, investigators here have found.

Patients reporting one or more traumatic or stressful events had a median disease-free interval of 31 months compared with 62 months for patients with no such events, Oxana Palesh, PhD, of the University of Rochester, and colleagues reported in the September issue of the Journal of Psychosomatic Research.

The findings support the view that traumatic or stressful events have long-lasting effects on stress-response systems, such as the hypothalamic-pituitary-adrenal (HPA) axis.

“This body of research may lead to a new understanding of psychosocial risk factors for disease progression and may result in novel interventions designed to buffer the adverse effects of earlier stressful or traumatic life events on the hyperactivation of the HPA axis and potentially ameliorate the impact of previous trauma and subsequent development and progression of cancer,” the authors concluded.

Despite a widely held belief that stress can influence the clinical course of breast cancer, research on the issue has yielded inconsistent results.

Several prior studies focused on dysregulation of the HPA response, which has an association with breast cancer progression, Dr Palesh and colleagues noted. Prolonged exposure to stress leads to HPA-mediated endocrine activation and increased production of cortisol, which diverts biological systems from normal functions to respond to the threat posed by stress.

“Extended periods of stress and trauma and its resulting cortisol production may interfere with the body’s ability to fight off cancer progression,” said Dr Palesh. “When there is consistent, long-term stress in the body, the elevated cortisol level may change the body’s normal rhythms and potentially reduce resistance to tumor growth.”

The current study involved 94 patients with metastatic or recurrent breast cancer. Thirty-nine reported traumatic life events, 27 reported a history of stressful events, and 28 reported no such experiences. Traumatic events included childhood sexual abuse, rape, life-threatening injury, or suicide of a family member. Stressful events included adoption, a parent’s death, living with a mother-in-law, earthquake, divorce, and imprisonment of a relative.

Patients in the 3 groups did not differ substantially in clinical and demographic variables.

Women with a history of traumatic events had a median disease-free interval of 30 months. Those with a history of stressful life experiences had a median disease-free interval of 37 months. In contrast, women reporting no such history had a median survival exceeding 5 years.

Although dysregulation of the HPA axis has been postulated as an underlying mechanism of increased risk in breast cancer, cortisol levels did not differ significantly among the 3 groups of patients. The finding is consistent with previous research showing “flattened” or lower cortisol levels in cancer patients compared with health controls.

The absence of cortisol elevations suggests “the physiology of metastatic breast cancer might have incremented any potential variability in cortisol itself that is usually present in healthy people and even in people with less severe cancer disease,” the authors said. “These findings support the disrupted feedback inhibition model of response to stress rather than the hypersensitivity as previously believed.”