Question: Why stress can produce us cancer?

Emily Mattacola answered on 19 Nov 2019:

Findings around whether stress is associated with an increased cancer risk are actually quite weak. Long-term studies which take a healthy person and follow them for a number of years to see if they develop cancer have not consistently found stress to be a risk factor for developing cancer, for example. What we suspect is that stress is only associated with developing cancer by the behaviours it encourages. When we’re stressed, we tend to engage in much poorer behaviours – we might smoke or drink alcohol to cope, we might overeat or eat lots of junk food, or stop exercising. All of these things have been found to have be associated with cancer over a long period of time. With this in mind, we think that stress might make us have poorer health behaviours, and these poorer health behaviours increase the risk of developing cancer.

What we’re more sure of is that stress affects the progression of cancer. That means that if you already have cancer, and experience stress, your outlook for how that cancer will develop is worse. For example, studies have found that stressful life events are associated with poorer survival from cancer. We’re not too sure what’s happening on a biological level with this, but we suspect it is to do with the way that stress hormones like cortisol damage our immune system, which means we’re less able to fight the cancer effectively, and might be more likely to develop complications from cancer treatment which we might die from, like pneumonia.