Extreme stress and cancer

Last month, I spent a few minutes scrolling through FaceBook groups of survivors of cancer. Many people in the group strongly believe that high levels of stress caused their cancer. They shared harrowing stories of finding out their spouse cheated on them, followed by divorce, bankruptcy, and rifts in the family. Then, cancer was the next blow of the sledgehammer. These survivors believed that all that misery in their life caused their cells to go beserk into cancer.

A couple days later, I had a session with a client, and started to wonder, ‘wait a minute, why do they not have cancer?’ They have unbelievable levels of stress in their life, between hiding from abusive ex’s, escaping a house fire in the middle of the night, and seeing one of their grown children wind up in jail.[i] Yes, their hair was falling out from stress, and they were very depressed, but they did not have cancer. I would not have been surprised at all if they told me they had cancer, but after working with them for many years, their body was still ok. Was there something that protected their body from stress turning into tumours?

Turns out, it is really hard to determine what aspects of extreme stress cause cancer, and what aspects of a person’s life protect them from cancer developing, even if their life is shattering. Yet this is what you want to know. We cannot control the ups and downs of life, but if we know what reduces the chances of stress turning into cancer, we can address those factors. But there is a problem. Studying stress is tricky. You would have to take a group of volunteers, randomly divide them into two groups, and then tell one group that you will subject some of them to a truly horrible experience. The most stressful thing that universities allow researchers to do to people are to have them immerse their hands in ice water for three minutes. Or, research subjects have to give impromptu speeches to judges who convey more disapproval than my mother-in-law.[ii] Yes, these are lousy experiences, but they hardly fall into the category of extreme stress. Nothing like the very painful situations that drag on for years, such as infidelity, divorce, bankruptcy. You cannot randomly assign humans to experience events like this either.

So, researchers tried another approach, using mice. One group of mice had been bred to by highly aggressive, while the other group was submissive. When researchers put them together, it was nasty. An aggressive mouse pounced on the submissive one, biting and drawing blood. Researchers did this daily for 20 days. This is the equivalent of 2.5 years for humans. Clearly, these mice were experiencing chronic and severe stress. Imagine being jailed and beaten daily for over two years.

When the researchers injected cancer cells into the mice, the growth rates were dramatically different. The mice who had been severely bullied had far more tumours than the control group. Meanwhile, the mice who had done the bullying, had 50 to 70% fewer tumours than their victims.[iii] Years later, another group of scientists found pretty much the same results, mice stressed by severe and chronic bullying had far more tumours than the control group who could chill in their cages. [iv] The more chronic the stress, the more tumours that grew.[v]

Turns out that whether the stress was chronic was a major factor. Mice exposed to just one stressful event were not likely to develop tumours, while those who experienced a variety of stressors for 2 months (equal to 7 years for humans) had twice as many tumours as the control group.[vi] These stressors were a real pain. The mice had their cages tilted sharply, shaken, stripped of bedding, or bed made wet, and were randomly attacked or totally immobilized. If I had to go through that every day for 7 years, yeah, my body would probably break down and sprout cancers as well.

After making the mice so miserable for so very long, Russian scientists tried medicating them. They used alcohol, (they are Russian after all)[vii], diazepam, and another med.[viii] The first two slowed tumour growth[ix], the last one did not.[x] This is an excellent place to remind you that treatments that work with mice often do not work with people. Alcohol is a known carcinogen, and diazepam is a benzodiazepine, which is highly addictive. It also substantially increases mortality.[xi] Just cause some mice in Russia had less cancer with chronic stress when they had vodka and Valium, does not mean that you should try this for yourself. That is a terrible idea, and if you do it, I shall have my mother-in-law fly out, ring your doorbell, and give you her most disapproving look possible.[xii]

The research helped scientists map out how chronic stress in mice translates into cancer. It actually turns some genetic switches on, and others off.[xiii] Tumours need blood vessels to carry nutrients to them, and the more blood vessels they have, the faster they grow. Chronic stress increases the chemical signal that causes blood vessels to grow (VEGF).[xiv] It also turns on the genes that promote cancer growth, and alters the genes that control cell death.[xv] All of this shows that chronic and severe stress alters biology on several different pathways. I described another pathway here. These many changes promote the growth of cancer.

At this point, you may be looking at your life and be on the verge of freaking out. You are dealing with serious stress. Does that mean you are doomed to get cancer for the first time, or have a recurrence? No, there are many factors that shape if people get cancer. In the next post, we will look at further research on mice to look at a powerful protective factor. It buffered the impact of the chronic stress and kept them healthier. We will look at how you can incorporate it as well, and dramatically reduce your chances of illness. In the meantime, leave a comment about your experiences with stress and cancer.