Does stress increase the risk of developing cancer? Does reducing stress speed up healing? I have recently been listening to a series of lectures by my hero, Professor Robert Sapolsky, called ‘Stress and your body’.1 During the course of the lectures, he addresses the various effects of stress on our health and covers the supposed link between stress and cancer. For a time, this link seemed certain and various studies gave it credence. However, as Dr Sapolsky points out, these studies were done retrospectively, after the cancer had been diagnosed and patients in the studies were asked about their recent stress levels. The excellent school of psychotherapy, Human Givens, points out that if we feel depressed and think about bad events in our life, then we remember more and more bad times. If we are given a cancer diagnosis, fear, worry and stress dominate thinking and we will be fixed on the negative events in our life. So any study based on asking people if their life was stressful before they got their cancer diagnosis is bound to find a strong correlation.
In due course, prospective studies began following the health of people to see if those most stressed had a higher incidence of developing cancer. Dr Sapolsky refers to a cornerstone study that apparently proved this link. It was a study done on Western Electric Plant workers in America that showed that those suffering from major depression were linked to a 2-fold increase in cancer rates. A couple of years after the study was published, the data was combed through again, and it was found that those with the major depression also had an awful boss who had them working in unsafe conditions with high exposure to carcinogens. So no surprise that they developed cancer there, the depression was a side effect. The bottom line is that there has been no proven link between stress increasing the risk of cancer.
Dr Sapolsky then went on to look at how stress lowers immunity and can this be the mythical link between stress and cancer? Long term stress lowers immune function without doubt; constantly pushing ourselves to reach goals without allowing recovery time will lead to catching more colds as our immune system buckles under the strain. However, the immune system has to be totally flattened to increase cancer risk – as in people with the AIDs virus, and even so, the cancer risk does not go up dramatically. From what I have learnt of cancer, it develops as a result of exposure to cancer forming agents – and there are enough of those about – with insufficient protection from anti-oxidants in the diet.
Then we have the hoary old chestnut about certain personality types having more risk of developing cancer – modern legends have them as introverted, suppressed people with anger issues. There is minimal evidence to show this and the feeble amount comes from retrospective and not prospective studies. Case dismissed -or maybe not, as we shall see.
Does stress affect cancer relapse? No evidence backs this claim up.
What about stress and the rate of cancer progression? Finally there seems to be a positive link here. And this is based on intervention studies, with the classic one being run by a colleague of Dr Sapolsky’s called David Spiegel. Dr Spiegel ran a study on a group of women diagnosed with metastatic breast cancer – a nasty development of primary breast cancer that spreads elsewhere. Not a good thing. The women were divided into 2 groups, the first receiving standard medical treatment and the 2nd group, standard medical treatment plus group therapy sessions, several times a week. The results of the study showed that the women in the 2nd group ended up with an increased lifespan by 18 months; which represents a very good bargain for such a dreadful cancer. So the initial assumptions were that group therapy led to feeling less stressed, an increase of immune system, and so an increase in cancer fighting ability. Other studies followed this one but about half had the same findings and the others failed to replicate it. So Spiegel re-examined his study and came to a very interesting, different conclusion.
The medication to kill cancer has horrible side-effects such as nausea, tiredness and maybe nerve problems: pins and needles, lack of sensation, difficulty doing up buttons; so hardly surprisingly, patients are not always compliant when it comes to taking the stuff. They also miss doctor’s appointments or may skip meals because they don’t feel like eating. What happened in the support groups was that the patients supported each other to take the pills, despite feeling terrible, to eat something, to see the doctor and with this greater compliance the medical intervention had more chance of succeeding.
And so we can now see the lack of proven connection between stress and cancer and we can see that joining a support group helps fight cancer because the patients encourage each other to take the horrible pills and brave the unpleasant side effects. Actively reducing stress if undergoing cancer treatment may help achieve a good recovery not by affecting the immune system but by reducing pain levels – more stress leads to greater pain sensitivity – and this can help a patient endure the side-effects and the endless visits to the doctor, further investigations and so on. And finally, the personality effect; some personality types will do whatever it takes – so will take the pills, eat regularly and so on to help themselves recover. Others do not share this attitude and, for whatever reason, are not so compliant with doctor’s orders.
So whilst there is no definite connection between stress causing cancer or affecting the outcome, being part of a support group will help with compliance in doing the necessary. And some people will endure the horribleness without any support at all because that that’s how they are.
- Stress and Your Body. 12 lectures given by Professor Robert Sapolsky of Stanford University. Course no. 1585 [↩]