Stress accelerates the development of pancreatic cancer by triggering the release of “fight-or-flight” hormones, a study has found. Beta-blockers – commonly used medications that inhibit these hormones – were found to increase survival in a mouse model of the disease, said researchers at the Columbia University Medical Center in the US. An additional analysis of patients with advanced pancreatic cancer revealed that those who were taking beta-blockers for another condition lived about two-thirds longer than those who were not taking the medications. Recent studies have shown that emotional and psychological stress play a role in the development of tumours in general. This effect is thought to occur through the sympathetic nervous system, which releases hormones that give the body a surge of energy so that it can respond to perceived dangers.
“Some biologists dismissed this idea because stress is hard to measure,” said Timothy C Wang, from the Columbia University Medical Center. “Others wondered how stress could possibly be related to a biological process that involves DNA mutations and the growth of cancer cells within a particular organ, such as the pancreas,” Wang said. The current study, published in the journal Cancer Cell, was designed to find the links between stress and early development of pancreatic cancer. The researchers studied mice that are genetically predisposed to developing abnormal growths in the pancreas. The mice were raised in stressful living conditions (confined to a small space), control mice were raised in normal housing.
After 14 weeks, 38 per cent of the stressed mice were found to have neoplastic pancreatic lesions, a precursor to pancreatic cancer. No such lesions were observed in the controls. “We know that you need a DNA mutation to start on the path to cancer, but our findings suggest that stress is doing something to move things along,” said Wang. That “something” was the subject of a subsequent experiment. Studies of the mice revealed that stress increases levels of catecholamines – the fight-or-flight hormones – in the bloodstream. “In other words, stress sets up what we call a feed-forward loop between nerves and cancer cells that promotes tumour development,” said Wang.
In experiments with a different mouse model of pancreatic cancer, the researchers demonstrated that treating mice with chemotherapy and beta-blockers lived significantly longer than mice treated with chemotherapy alone. They also looked at survival in 631 patients who had surgery to treat advanced pancreatic cancer between 2002 and 2013. Those who were taking non-selective beta-blockers after surgery had a median survival of 40 months, about two-thirds longer than patients taking selective beta-blockers, which affect fewer targets in the body, or neither type of beta-blocker.