Chronic stress, sympathetic activation and skeletal metastasis of breast cancer cells.

Improved detection programs and new therapies significantly improved the 5-year survival rate of women with breast cancer. However, some women still relapse and succumb to cancer because of metastatic disease. In particular, chronically depressed patients do not seem to benefit from newly developed treatments and present with shorter survival. The reason for this association is unclear, but recent cues from preclinical studies point to the possible contribution of neuroendocrine factors generated in response to chronic stress and depression. Retrospective clinical studies also suggest a beneficial effect of sympathetic blockade in terms of less advanced disease at diagnosis, lower cancer-specific mortality, longer disease-free survival and reduced metastasis development and tumor recurrence, especially in patients who have taken propranolol before diagnosis. Therefore, β-blockers or therapies normalizing sympathetic tone might be beneficial as early adjuvant therapies to limit skeletal metastases and growth and eventually to improve prognosis in patients with breast cancers.