As the world observes world Cancer Day 2013, which is celebrated in February of every year, this year will focus on Target 5 of the World Cancer Declaration: Dispel damaging myths and misconceptions about cancer, under the tagline “Cancer – Did you know?” World Cancer Day is a chance to raise our collective voices in the name of improving general knowledge around cancer and dismissing misconceptions about the disease.
However, to reduce patients’ burden, the minister of health, Prof. Onyebuchi Chukwu, has said that plans are on the way to include cancer screening and treatment, as part of the services offered by the National Health Insurance Scheme (NHIS) and make the scheme mandatory.
For the purpose of this discussion, we shall address the nitty gritty of cancer, and how it can be prevented.
Cancer is a group of more than 100 different diseases that can begin almost anywhere in the body. It happens when normal cells in the body change and grow uncontrollably. These cells may form a mass called a tumor. A tumor can be benign (noncancerous) or malignant (cancerous, meaning it can spread to other parts of the body). However, some cancers do not form solid tumors. These include leukemias, most types of lymphoma , and myeloma (cancer of the plasma cells in the bone marrow, the spongy tissue inside of bones).
Causes of cancer
There are many things that can cause cancer – and many things that people wrongly believe cause the disease. And for many cancers, we simply do not know the cause.
The fundamental cause of cancer is damaged or faulty genes – the instructions that tell our cells what to do. Genes are encoded within DNA, so anything that damages DNA can increase the risk of cancer. But a number of genes in the same cell need to be damaged before it becomes cancerous.
Most cancers are caused by DNA damage that accumulates over a person’s lifetime. Cancers that are directly caused by specific genetic faults inherited from a parent are rare. But we all have subtle variations in our genes that may increase or decrease our risk of cancer by a small amount.
So cancer risk isn’t “all in the genes”, and it’s not all down to lifestyle – it’s a combination of the two. We can’t change our genetic makeup, but we can all take steps to reduce our risk of cancer by following healthy lifestyle advice based on scientific research.
However, the factors below can make some people more prone to cancer than others.
Age is the single biggest risk factor for cancer – the older you are, the more likely you are to develop cancer. Nearly two-thirds of all cases of cancer diagnosed in the UK occur in people over 65 years old. This is because the longer we live, the more cancer-causing faults we accumulate in our DNA.
It also explains why more people are getting cancer nowadays. Thanks to advances in public health and the prevention of infectious diseases, we live much longer, increasing our chances of picking up cancer-causing DNA faults.
Up to half of all cancers could be prevented by changes to lifestyle, and there are many things we can do to try to reduce the risk of the disease.
These include giving up smoking, enjoying the sun safely, eating a healthy balanced diet, limiting alcohol, keeping physically active and sticking to a healthy bodyweight.
There is much more detailed information about lifestyle and cancer risk in our Healthy Living pages.
DNA damage is extremely common – some studies suggest that the DNA in a single human cell gets damaged over 10,000 times every day.
For a start, the life-sustaining chemical reactions that occur naturally in our cells generate harmful by-products, and these can cause DNA damage. So, merely being alive leads to DNA damage, and this can potentially cause cancer.
Also, our everyday surroundings are full of things that constantly damage the DNA in our cells, known as carcinogens.
Although our cells are very good at repairing this damage, errors can accumulate over the years. This explains why cancer usually affects older people.
‘Carcinogen’ literally means ‘something that causes cancer’. Carcinogens damage DNA, causing faults in important genes that can lead to cancer. Examples include:
- Car exhaust fumes and air pollution
- The sun
- Natural and man-made radiation, such as radon gas or X-rays
But it is a mistake to believe that exposure to carcinogens is the only cause of cancer. In almost all cases, carcinogens are contributing factors, but there is a whole host of other factors at work, including a person’s lifestyle and genetic makeup.
Inherited gene faults
Some people are born with a fault in one of their genes. This does not mean that they will ever actually develop cancer, but it does mean that fewer other things need to go wrong with the rest of their DNA for the disease to develop.
For example, women born with a mutation in one of their BRCA genes have a much greater chance of developing breast and ovarian cancer than women who do not. Faults in a BRCA gene can also increase a man’s risk of prostate cancer.
People with a strong family history of these cancers can go for genetic testing, to find out whether they carry the faulty gene. Those at risk may be offered