High stress levels cause cancer to spread: Australian study

Australian researchers have established a link between high levels of stress and the spread of cancer, in a study that could affect the way doctors treat the disease.

The researchers, from Melbourne's Monash University, established that the psychological effects of stress can cause cancer cells to multiply and transfer to other parts of the body.

The results of the study were published in the well-respected journal, Nature Communications, on Wednesday.

Until now, the theory that stress impacted a patient's chances of surviving the deadly disease had not been documented by scientists.

While studying mice, the team observed that adrenaline - a naturally occurring chemical triggered by stress - detrimentally affected those animals with cancer, increasing the size in and around lymphatic vessels due to more fluid passing through them.

The increased flow of this fluid then carries the disease - estimated to kill around 50,000 Australians each year - through what the Melbourne-based researchers describe as the "lymphatic highway," causing it to spread.

"We found that chronic stress activates the sympathetic nervous system (SNS) - better known as the 'fight-or-flight' response - to profoundly impact lymphatic function and the spread of cancer cells," Dr Caroline Le, one of the study's lead researchers, said in the final report.

"These findings demonstrate an instrumental role for stress ... and suggest that blocking the effects of stress to prevent cancer spread through lymphatic routes may provide a way to improve outcomes for patients with cancer."

The study also tested the effects of stress on humans with the disease, specifically breast cancer, finding that it was less likely to spread when the group was given drugs to treat anxiety.

A clinical trial is currently underway at a local cancer center to test if these anxiety pills can produce the same results on a mass scale. Endit