By Dr. Kirsty McIntyre MBBS, FRACGP, MPM, FRANZCP
A major advance in cancer research over recent decades has been the recognition that a healthy immune system is necessary to both prevent and survive a cancer diagnosis.
Whilst some of us have inherited genes that put them at higher risk of leiomyosarcoma (for example, retinoblastoma and Li Fraumeni syndrome) the majority arise from random mutations; our bodies are constantly making copies of our own cells and every now and then a slight error can occur in a copy of a gene – a mutation. Over time these can accumulate and if they affect the areas on the genes that regulate growth, can result in unrestrained growth, or as we know it, cancer.
Fortunately for most people a healthy immune system is constantly on the lookout for aberrant cells- to identify and kill them. This is why people with long term weakened immunity- those taking immune suppressants- for example, after an organ transplant, are more prone to developing cancers, including some types of sarcoma.
Simply growing older results in a weakened immune system, which combined with a lifetime of genetic mutations explains why cancer is so much more prevalent as we age.
To survive in the body- cancer cells must trick the immune system into thinking they are not a threat. Much immunotherapy research is centred on trying to help the immune system recognize where this is happening. For example- the checkpoint inhibitors take the brakes off a particular type of immune cell called a T cell- so that it is more free to seek out and kill cancer cells. Studies of leiomyosarcoma (LMS) specimens has found a link between higher T cell infiltrates around the tumor and a better outcome- indicating that the patient’s own immune system has become activated to fight LMS.
Lots of research is currently underway looking at ways to boost innate immunity- including drugs to modify immune suppression caused by cancer cells (immunotherapy), as well as vaccines and even growing T cells matched to your cancer in a lab before infusing them back into your body (CAR-T). Unfortunately these are still experimental and cancer has lots of tricks available, so we are yet to find a really effective tool in LMS.
So what can we do in the meantime-rather than feeling helpless- to ensure our immune systems are as working as effectively as possible? Once diagnosed, the aim of surgery, radiation, hormonal and chemotherapy is to reduce the vast bulk of cancer cells in the body. But what you then need is for your immune system to be able to mop up some of the remaining, individual cells. And whilst they are at it – protecting against viral and bacterial infection! Fortunately there are several lifestyle decisions listed below, such as exercising, sleeping well, and a healthy diet that can help you maximise your immunity.
Exercise; whilst there is no LMS specific data, the Nurses Health Study showed that regular exercise- the equivalent of walking 3-5 hours/week- halved the risk of death or recurrence in those with breast cancer, compared with those who did the least amount of exercise. Similarly, there are indications that those who exercise regularly are less likely to catch colds and influenza. At least part of the benefits of exercise appear to be mediated by enhanced immune function.
Sleep is also important for a well functioning immune system- elevating the levels of circulating T cells. Conversely, those who are sleep deprived are more prone to infections.
Vitamin D: The relationship between vitamin D levels and immunity has been clearly established. Several studies show that shingles for example, which represents a very late resurgence of a childhood chicken pox infection, as well as colds and influenza are more common in those with lower vitamin D levels. Several cancers like bowel cancer, are also more common in populations with the lowest vitamin D levels. It’s harder to prove that supplementing makes a difference but it’s something to think about- especially if you have an indoor lifestyle with little sun exposure.
A healthy diet, rich in fruits and vegetables and avoiding alcohol/tobacco is essential to promote immune health. Many natural supplements such as rice bran oil or quercetin have claims around promotion of immune health and these are easily sourced from a healthy diet. Intermittent fasting also is integral to many cultures with some evidence that it may promote immune health.
Psychological health is also important with clear links between mental illness and immune disturbances, and evidence of improved immune function in those who meditate.