Elevated Stress Hormones May Awaken Sleeping Cancer Cells

First, stress hormones are not the same thing as stress, and we are not referring to the old association of stress or poor anger management causing cancer. This is an important distinction. The recurrence of cancer long after seemingly successful treatment is a puzzle that has confounded doctors and researchers. Why do lingering cancer cells suddenly become active?

...it is critical to remember that no one is suggesting that stress causes cancer or reawakens dormant cancer cells.

This can happen in many types of cancer but is especially a problem for ER-positive breast cancer. Although it is uncommon, I have known women whose breast cancer returned years after the initial diagnosis and treatment. This reality means that it is hard to grow beyond the worry. Time helps all of us feel less anxious about a possible cancer recurrence, but the facts can be unsettling.

A recent study, published in Science Translational Medicine, describes how a cascade of events can cause long-dormant cancer cells to become active again. These events begin when a stress hormone, norepinephrine, that is naturally found in our bodies, is released at higher-than-normal levels. This hormone stimulates neutrophils, a type of white blood cell, to release a special form of lipid that awakened the sleeping cancer cells.

Like so much cancer and other research, most of the work was done on mice. However, the group also considered 80 lung cancer patients who had undergone surgery to remove their tumors. Seventeen of these people had early recurrences, that is their cancer returned within three years of surgery. As compared to the other 63 people whose cancer either recurred later or never, they had higher levels of norepinephrine. Important note: this is one study that will need to be replicated and tested on people with other types of cancers.

Let’s go back a little here. What are dormant cancer cells? They are cancer cells that are left after cancer treatment but are undetectable. As long as they stay quiet, it is not a problem. The problem, a recurrence of cancer, only happens when/if they become active. No one understands how or why or when this happens, so this study is an important hypothesis that will stimulate more research and, hopefully, answers.

Stress in this study means stress hormones and there are many in our bodies. These researchers looked at only one of them, norepinephrine. Everyone has stress in their lives, and it is critical to remember that no one is suggesting that stress causes cancer or reawakens dormant cancer cells. Stress hormones do lots of other things, and we need them in our bodies.

For this sequence of events, a perfect storm of sorts, norepinephrine needs to be produced in larger than usual amounts, to stimulate neutrophils and for them to produce a particular lipid that can turn on the sleeping cancer cells. This is not a simple process and definitely is not started because you are worrying about finances or COVID-19 or someone whom you love.

In addition to the need for more studies to try to replicate and expand these findings, scientists and doctors will need to identify ways to use this information clinically. These endeavors are sometimes called from the bench to the bedside and mean that tantalizing science needs to be framed in ways to directly impact patients. One suggestion in the study was that the level of stress hormones be measured during and after treatment; if they begin to rise, it could be an early warning sign of a recurrence.

Again, I feel the need to emphasize that nothing about this study is telling us that stress causes cancer. We have spent years trying to dissuade people from this worry. It is especially important in my practice, because cancer diagnosis and treatment itself is inevitably stressful; it would be impossible go to through these months without worry.

Those worries absolutely do not bring on cancer. When others suggest that you need to think positively, it can bring on a circle of concern: I am scared so I am stressed so I am making the cancer worse and that makes me more scared. That is fairly described as magical thinking, all too easy to experience. And just plain not so.

Think of this study as another step towards helping us understand cancer’s behavior and helping, hopefully, more and more of us stay well.