2. Chronic Stress Makes Cancer Spread
Most recently, a study done on mice found that when the animals were chronically stressed, their lymphatic systems underwent changes that allowed cancer to spread more quickly and easily. As reported by Science Alert:1
“Although the study hasn’t been replicated in humans as yet, it’s a huge step towards understanding how stress – which has long been linked to cancer progression – actually helps tumour cells escape…
“Not for a minute are we suggesting that someone who’s just been diagnosed with cancer should not be stressed, because that would have to be one of the most stressful situations”… Erica Sloan from Monash University in Australia, told ABC News.2
“But rather how do we look after cancer patients, because this suggests that stress not only affects patient wellbeing but also gets into the body and affects how the tumour progresses.”
How Does Stress Promote the Spread of Cancer?
Cancer cells typically spread to other areas of the body either via your blood vessels, or through your lymphatic system. Stress hormones affect both of these pathways or channels. Here they were trying to determine how stress hormones affect the spread of cancer cells through the lymphatic system.
The mechanism they found is related to the way adrenaline activates the sympathetic nervous system (SNS) to increase the rate of lymph formation. Adrenaline also causes physical changes in the lymph vessels, allowing cancer cells to migrate into other body parts at a faster rate.
The National Cancer Institute has also previously stated that research with animal models suggests:3
“[Y]our body’s neuroendocrine response (release of hormones into your blood in response to stimulation of your nervous system) can directly alter important processes in cells that help protect against the formation of cancer, such as DNA repair and the regulation of cell growth.”
Norepinephrine can stimulate tumor cells to produce two compounds (matrix metalloproteinases called MMP-2 and MMP-9) that break down the tissue around the tumor cells, thereby allowing the cells to more easily move into your bloodstream.
Once there, they can travel to other organs and tissues and form additional tumors.
Norepinephrine may also stimulate tumor cells to release a chemical (vascular endothelial growth factor, or VEGF) that aids the growth of the blood vessels that feed cancer cells. This too can increase the growth and spread of the cancer.
Epinephrine — yet another stress hormone — has also been found to cause changes in certain cancer cells, specifically prostate and breast cancer, in ways that makes them resistant to apoptosis (cell death).
This means that emotional stress can both contribute to the development of cancer and reduce the effectiveness of treatments.6
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