This blog is the 3rd in a series of 5 on the topic of cancer written by Dr Philip Borg MD FRCR FAAMFM.
Dr Borg is a Consultant Cancer Interventional Radiologist and a Longevity Medicine Specialist.
In the previous blogs we learnt about the signs and symptoms of cancer and the importance of catching cancer in the early stages.
1 in 2 people will develop some form of cancer in their lifetime and 38% of cancers are preventable and due to modifiable risk factors - lifestyle factors we can change. This blog will focus on what you can do to reduce your risk of developing cancer.
How does cancer develop? Cancer is a disease caused by changes in the genes (DNA) that control how cells grow and function. Most cells in our body multiply in a very highly controlled way (humans are made up of 30-40 trillion cells). A good analogy is to think of genes (DNA) as the cell’s operating system - genes control how the cell functions. When genes are damaged they are either repaired or the cell cannot function properly.
Genetic changes can occur:
When a cell multiplies
Damage to the DNA from our environment
Inherited changes from our parents.
Cells with damaged DNA are normally detected and removed by the body’s immune system. As we grow older our immune system becomes less effective, this is one of the reasons why cancer is more common later in life. Interestingly, forest bathing or exposure to nature has been shown to increase the number of cells that can detect cancer cells (NK T-cells) and remove them from your body.
Inherited genes from our parents that increase the risk of cancer cause 5-10% of cancers; we cannot change this risk but it is important to look for early signs and symptoms if cancers and ensure we screen early for detectable cancers. A family history of cancers can be a sign of inherited cancer syndromes and genetic screening tests may be appropriate after consultation with your doctor.
Lifestyle changes you can make to decrease your risk of cancer
We can control some of the risk of cancer caused by damage to our DNA from our environment.
Cigarettes contain at least 69 carcinogenic (cancer-causing) compounds including hydrogen cyanide and ammonia. Smoking doesn’t only cause lung cancer. Carcinogens in cigarettes are absorbed in all tissues in the body and can increase the risk of developing cancer of the stomach, large bowel, liver, pancreas, kidneys, bladder, leukaemia as well as the more obvious cancers in the lungs, mouth and throat.
Second hand smoke (being around people who are smoking) also increases the risk of cancer in adults and children. Smoking by parents increases the risk of leukaemia (ALL) in children through second hand smoke as well as DNA changes in sperm and eggs from the parents. The genetic changes that increase cancer risk can even be found in children whose parents had quit smoking before the baby was conceived.
2. Obesity and being overweight
Having too much fat is associated with poor metabolic health. Overeating and lack of exercise can lead to excess fat which is associated with insulin resistance and an inflammatory state in the body known as metaflammation. The high insulin levels and inflammation promote tumour growth all over the body. By maintaining a healthy weight you reduce your risk of developing many cancers including bowel, liver, breast, stomach and pancreatic cancers. Previously physically active patients who are treated for cancer, are less likely to develop a recurrence of their cancer compared to patients who were inactive.
3. UV exposure
Certain types of radiation such as UV radiation from the sun, can also damage DNA and therefore increase risk of developing cancers including non-myeloma skin cancer, leukaemia, and thyroid cancer. Enjoying the sun safely is an important way of reducing your cancer risk.
Drinking alcohol increases risk of cancer of the liver, breast, mouth, throat and oesophagus. This risk is increased in people who also smoke tobacco. If you are going to drink alcohol, drink in moderation, take up to 1 glass of red wine per day and take regular breaks of 4-5 days from drinking.
5. Eat a high fibre diet and avoid processed meat
A western diet, particularly one high in red meat and processed meats, is associated with an increase in cancer particularly large bowel cancer.
This may be the cause of the rapid increase in the advanced colorectal cancer in people aged under 40. People born after 1990 are now twice as likely to be diagnosed with colon cancer and four times more likely to get rectal cancer compared to people born in 1950. A diet high in fibre (fruit and vegetables) is protective.
Certain types of cancer can be caused by viral infections. Vaccines against human papilloma virus (HPV) and hepatitis B and C are highly effective against developing infections which cause cervical and some types of liver cancer.
Can you make sure you don’t get cancer? The answer is no. Cancer prevention strategies will reduce your risk, however it is important to look out for early signs and symptoms. In our next blog we will discuss cancer screening including a new technology which can analyse blood to detect cancer before it can cause signs and symptoms.