There is contradictory research findings showing a link between stress and cancer causation. However, there is more research showing a solid relationship between chronic stress and the progression of cancer. The major cause of death in cancer is from metastasis and to decrease the risk of this outcome for cancer patient interventions should be directed toward destroying the cancer cells and making the human host more resistant .
Some of the research on the relationship of chronic stress and cancer metastasis follows:
In a 2010 study of stress and cancer progression published in Cancer Research researchers concluded stress significantly accelerated breast cancer in mice. The said stress reprogramed the immune cells that are trying to fight the cancer transforming them from protectors of the body to aiders and abettors. They found a 30 fold increase in cancer spread throughout the body of stressed mice compared to those that were not stressed.
A 2013 study reported in the Journal of Clinical Investigation concluded that stress can both reduce the effectiveness of cancer drugs and also increase the growth of cancer tumors. In the study mice with human prostate cancer were given a clinical trial prostate cancer drug. When the mice were kept calm and stress free the drug destroyed cancer cells and inhibited tumor growth. However, when the mice were stressed the drug did not destroy the cancer cells and did not inhibit tumor growth. In a second model, mice genetically modified to develop prostate cancer were repeatedly stressed and the size of the prostate tumors increased. When the mice were treated with bicalutamide, a drug used to treat prostate cancer, their prostate tumors decreased in size. However, when mice were repeatedly stressed, the prostate tumors didn’t respond as well to the drug. In both studies, the mice were subsequently given a beta-blocker–a drug that inhibits the body’s release of adrenaline, with the effect of slowing down heart rate, blood pressure and other bodily functions. The results showed that administering a beta-blocker prevented stress from accelerating tumor growth.
Another study published in the Journal of Clinical Investigation in 2013 concluded that stress fuels cancer by triggering a ‘master switch’ gene known as ATG3 that allows the disease to spread. The cancer cells somehow coax immune-system cells recruited to the site of a tumor to express ATF3 to fuel cancer. Researchers first linked the expression of ATF3 in immune-system cells to worse outcomes among a sample of almost 300 breast cancer patients. Experiments on mice then found those lacking the gene had less extensive spread of breast tumor cells to their lungs than ones that could activate it. They found that if the body is in perfect balance, there isn’t much of a problem. When the body gets stressed, that changes the immune system.