In keeping with other studies, this study indicates that chronic stress does not "cause" cancer, but may affect the progression and metastasis of existing cancer.

http://www.the-scientist.com/?articles.view/articleNo/45476/title/How-Stress-Affects-Cancer-s-Spread/

And these researchers provide further evidence for beta-blockers (like propranolol) as a potential treatment. "Administering beta-blockers to tumor-bearing mice, the researchers were able to minimize changes in the density of lymph vessels at the primary tumor site, and subsequently reduce metastasis to the lymph nodes."

"The study also included an analysis of observational data from a cohort of nearly 1,000 breast cancer patients in Milan, which corroborate the team's findings in mice: patients taking beta-blockers showed a significantly lower incidence of lymph node and distant metastases, even once potentially confounding factors such as age and treatment type had been taken into account."

Of course we don't have to look at just drugs for stress management. Cognitive behavioral therapy (CBT), meditation, yoga, and other stress reduction techniques could all be helpful. The following article is about research that found survival benefits for BC patients trained in CBT techniques.

http://www.sciencedaily.com/releases/2015/12/15120...