Cancer is one of the world’s leading causes of death, second only to atherosclerotic heart disease.
On average, one in five of us will be diagnosed with cancer in our lifetime and it touches practically everybody’s life, either directly or indirectly, at some point.
Despite the survival rates of certain types of cancers increasing dramatically, mainly due to early detection, improved treatment protocols and discovery of novel therapeutic agents, cancer incidence is increasing worldwide.
In 2022, some 20 million cases of cancer were diagnosed globally and this is expected to rise by 77 per cent to 35 million global cancer diagnoses in 2050, according to the World Health Organisation.
In the past 30 years, cancer patients have become younger (below 50) and these cancers tend to be more aggressive in nature.
Cancer is a disease in which some of the body’s cells grow uncontrollably and may spread throughout the body. It can start anywhere in the body and can grow in different organs and from different cell types so one may think of cancer as a set of diseases which can behave differently on this basis.
The uncontrollable multiplication of cells which defines cancer is caused by changes in the DNA which is due to numerous interacting factors – some of which cannot be changed like genetics and some which can, for example, through lifestyle factors.
Ten per cent of all cancers are caused by inherited genetic changes, while approximately 40 per cent may be prevented. In other words, there are things we can modify in our behaviour and lifestyle which can reduce our risk of developing cancer. These are termed modifiable risk factors. It is these factors which are driving the increases in cancer rates and the large increase in aggressive cancers in younger patients. These include obesity, tobacco use, alcohol consumption, poor dietary habits and environmental factors, including air pollution.
Tobacco use is the biggest cause of cancer: it is the primary risk factor for lung cancer but also increases the risk of developing cancer in almost any other part of our body, including kidney, liver, bladder, mouth, pancreas and colon. Second-hand smoke − being around people who are smoking − also increases the risk of cancer.
By maintaining a healthy weight and body composition, you reduce your risk of developing over 20 types of cancers
Parents who smoke also increase the risk of giving birth to children at an increased risk of developing leukaemia later on in life. There is no safe level of tobacco use and quitting smoking, regardless of age or duration spent as a smoker, substantially increases life expectancy.
The risks associated with smoking tobacco are today widely recognised. What is less well known is the role being overweight or obese plays in causing cancer − it is the second-most prevalent environmental risk factor for cancer development. Having excess fat increases cancer risk though multiple routes. These include increased levels of low-grade chronic inflammation throughout the body and increased levels of certain substances in the body which stimulate cell growth.
By maintaining a healthy weight and body composition − having a healthy proportion of fat and muscle mass − you reduce your risk of developing over 20 types of cancers, including breast, colorectal, liver, thyroid, pancreatic and gallbladder. Therefore, achieving and maintaining a healthy weight by not consuming excess calories reduces your risk of developing many types of cancers.
Alcohol consumption is also a risk factor for cancer development. Excessive consumption beyond the recommended 14 units per week increases your risk of developing liver, mouth, breast and colorectal cancers. This risk increases exponentially with increased consumption. Occasional low-to-moderate alcohol consumption appears to have minimal cancer risks overall and does have some benefits for healthspan and lifespan by increasing social interaction.
Diet is one of the cornerstones of living a long life in good health, so it is no surprise that having a nutritious and balanced diet reduces your risk of developing certain cancers. In particular, a diet high in fibre (from fruit, vegetables and other plant-based whole foods) and one with minimal ultra processed foods (especially processed meats) is associated with a reduced risk of bowel cancer.
Avoiding or minimising exposure to certain environmental cancer-causing agents is also important in reducing your risk of developing cancer. This would include
protecting yourself from harmful UV radiation from the sun by enjoying the sun safely, thereby reducing your risk of skin cancer, as well as other cancers such as thyroid and leukaemia. As much as possible we should also avoid pollutants such as those present in the air.
Additionally, there are a few types of cancers caused by viral infections whose development may be avoided through vaccination. These include the vaccines against human papilloma virus (HPV) and hepatitis B and C, which are highly effective at preventing infections which cause cervical and some types of liver cancer, respectively.
So although we cannot ensure we do not get cancer, there are many strategies we can incorporate into our lifestyle which will significantly reduce our risk. As always talk to your doctor if you have any signs or symptoms of early cancer such as unexplained weight loss, unexplained lumps, pain, bleeding or bruising.
Furthermore, detecting cancer in earlier stages greatly increases your chances of survival − being aware of the early signs and symptoms of cancer, as well as timely cancer screening tests, are vital.
Philip Borg is a longevity medicine specialist, as well as a consultant interventional radiologist. He leads The Longevity Clinic at St James Hospital.