A new animal study has determined the process long term stress triggers to allow cancer cells to spread (metastasize) throughout the body. Metastasis is the major cause of death from cancer is metastasis that is resistant to conventional treatment. Over the last 30 years many studies have identified psychosocial factors including stress, chronic depression and lack of social support as risk factors for cancer progression. In particular, depression and hopelessness, both have stronger relationships with outcomes than do stressful events, suggesting that sustained activation of negative affective pathways may provide the strongest links to cancer progression. Influencers of stress, such as social support, have been frequently studied with respect to cancer outcomes. Social support refers to an individual’s perceived satisfaction with social relationships and is thought to play a major role in buffering psychological and biological stress responses.
Several studies have linked high levels of social support to improved clinical outcomes in cancer patients. For example, in breast cancer patients, social support has been related to longer survival in several large-scale studies, although negative findings were noted in some studies.
Emerging evidence has shown stress and specific psychosocial factors to be associated with key elements of the metastatic cascade in both animal and human models.
The research, led by Australian scientists, also showed that a well-known blood pressure drug may reduce the risk of the cancer spreading.
In a paper recently published in Nature Communications, those scientists report how exposure to chronic stress not only increases the number of lymphatic vessels draining from the tumor, but increase flow in existing vessels.
"So not only do you get new freeways out of the tumor but the speed limit is increased and so the tumor cells can flow out of the tumor much more rapidly," said one of the study's authors, Dr Erica Sloan from the Monash Institute of Pharmaceutical Sciences.
Previous studies have shown that stress hormones such as adrenaline and noradrenaline can influence blood vessel formation, which is important in the spread of disease.
The lymphatic system — a vital part of the immune system that comprises a network of tubes throughout the body that drains fluid from tissues back into the bloodstream — can also promote the spread of cancer, but whether this can be influenced by stress had been unclear up to now.
"That was one of the key findings of this study, because we can identify that it's adrenaline acting through particular receptors on cells, and that tells us what drugs we should use to block these pathways," Dr Sloan said.
This suggests that stress not only affects patient wellbeing but also gets into the body and affects how the tumor progresses.
Can a Drug Interrupt the Stress Response?
To test this, researchers used a drug called propranolol to block the action of adrenaline in the stressed mice.
A type of drug called a beta-blocker, propranolol has been used widely for nearly half a century to treat blood pressure.
When the stressed mice were treated with the drug, it stopped their stress hormones from remodeling the lymph vessels inside the tumor, and reduced the risk of the cancer spreading through the lymph nodes.
Because propranolol and other beta-blockers are already in widespread use around the world, Dr Sloan and her colleagues looked at data from nearly 1,000 breast cancer patients in Italy to see if any were taking beta-blockers and, if so, whether it showed any effect on their risk of metastases.
"When tracked over about seven years, it turned out that those that had been taking beta-blockers also showed far less evidence of tumor cells moving into the lymph nodes and then disseminating to other organs like the lung, so it provides clinical support for what we see in the mice," said Dr Sloan.
Pilot Study on Women with Cancer
The team is now conducting a pilot study in a group of women with breast cancer to see if treatment with propranolol will reduce their risk of the tumor spreading to other parts of the body.
Dr Sloan said a link between chronic stress and cancer spread — but not new cancer — has now been shown in several studies, particularly in individuals with early stage disease, which highlights an opportunity to reduce both stress and the risk of metastases or secondary tumors.
"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," she said.
"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 tumor progresses."
Medical oncologist Associate Professor Elgene Lim, from the Garvan Institute, said the study provided a possible mechanism to explain the observation from many previous studies that stress was associated with poorer outcomes in cancer.
"What also makes this study exciting is the affordability of [possible] interventions," said Professor Lim, who was not involved in the research.
But, he emphasized, the blood pressure drug needed to be tested in clinical trials to see if it reduced the spread of cancer in humans.
A Better Stress Management Solution
It is interesting that Propanolol is linked to interrupting the stress response. However, it is a beta blocker, and its impact has significant side effects that impair the quality of life. It slows the heart rate and prevents normal increases associated with exercise and exertion. So I think it would be wise, to consider proven stress management techniques instead of a drug.
I have watched numerous patients achieve remarkable results simply using mind-body techniques as an adjunct to their treatment for a variety of cancers. Studies have shown that meditation, cognitive restructuring, as well as other mind-body techniques have helped to improve not only their quality of life, but their outcome.
When we create a healthier environment, it allows our body to function normally-with ease, and that state of functioning helps to improve and reverse the course of countless diseases.