A new study published yesterday in the journal Cancer suggests that a common medication known as a beta-blocker, taken by millions of people for heart problems and anxiety, could significantly improve survival for patients with ovarian cancer.
The study, led by Anil Sood, M.D., at The University of Texas MD Anderson Cancer Center, looked at 1,425 patients who were treated for cancer between 2000 and 2010. Those taking a common form of beta-blocker for a heart condition unrelated to their cancer had an average survival of 94.9 months, compared to 38 months for patients not taking a beta-blocker. That’s an improvement in survival of more than 4 years.
“We found that patients taking a broad, or non-selective, beta blocker were the ones who derived the most benefit," Dr. Sood said.
The study is not the first to look at the role of beta blockers in cancer treatment. Past studies have also shown an association between beta-blocker use and less risk of metastasis in breast cancer. And laboratory studies have shown a direct effect of beta-blockers on cancer in mice.
A larger body of work has also looked at the flip side of the equation—the role of stress in cancer progression. Chronic stress has been shown to promote the growth and spread of cancers, in part by activating the so-called “fight-or-flight” response. This is the survival instinct that is triggered by stress hormones like adrenaline (also called epinephrine) and norepinephrine, and that leads to characteristic physiological changes like a rapid heartbeat and sweaty palms. The hormones work by binding to bits of machinery on cells called beta-adrenergic receptors. Beta-blockers prevent the binding of stress hormones to the receptors (hence the name), and thus prevent the fight-or-flight response.
Studies over the past decade, by Dr. Sood and others, have shown that cancer cells have these receptors, too, and that their activation by stress hormones can promote cancer cell survival and metastatic spread.
That’s not the end of the influence. It’s long been known that stress negatively affects the immune system. This is another potential way that beta-blockers may confer a benefit to cancer patients—by blocking the suppression of immune function.
On this last point, the Cancer Research Institute is funding the work of Ming O. Li, Ph.D., an immunologist at Memorial Sloan Kettering Cancer Center through a Clinical and Laboratory Integration Program (CLIP) grant. Dr. Li is looking at the role that signaling through beta-adrenergic receptors on specific immune cells called T cells has on the ability of these cells to fight cancer.
Dr. Li’s results so far suggest that the activation of these receptors on T cells dampens their cancer-killing abilities, which suggests that beta-blockers work in part by relieving this immune suppression. By revealing the downstream targets of stress hormone signals in immune cells, his work may also point to new potential targets for immunotherapy—for breast, ovarian, and other cancers.
Importantly, in the recent study of ovarian cancer, the greatest benefit in survival was seen for patients taking so-called non-selective beta-blockers—those blocking all types of beta-adrenergic receptors in the body—rather than selective beta-blockers—which target only one type. The most common type of non-selective beta-blocker is called propranolol.
The leaders of the recent Cancer study suggest that it is too soon to recommend that cancer patients take beta-blockers as therapy. There can be significant side effects of the drugs, especially for certain subsets of patients. But it is an interesting possibility, and with further study could lead to that end.
Clinical trials of the drugs, for patients with breast and ovarian cancer, are currently under way.