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Many people worry about getting cancer. Sometimes people think they have a higher risk of developing cancer because there has been cancer in their family. This section explains:
How uncommon it is for cancer to run in families.
What we know about the main causes of cancer.
What you can do to help yourself.
The cause of cancer in most people is not known. But we know that some things – called risk factors – can increase our chances of developing cancer. Some risk factors are very likely to cause cancer, whereas others will only very slightly increase our likelihood of getting it.
Having a particular risk factor for cancer, or being exposed to one, doesn’t mean that we will definitely get cancer; just as not having it doesn’t mean that we won’t. Smoking is a good example of this. If you smoke, it isn’t certain that you will get lung cancer; just as if you don’t smoke, it’s not certain that you won’t. But smoking will greatly increase your risk of getting lung cancer. Nine out of ten people who develop lung cancer are smokers.
Cancer is very common and nearly one in three of us will develop it at some time during our lives. This means that most of us will have relatives who have had cancer. Surveys have shown that many people are worried that a history of cancer in their family greatly increases their risk. People often worry that an increased risk of cancer can be inherited, or passed on from one generation to another. In fact less than 1 in 10 cases of cancer (between 5 and 10%) have been shown to be due to a family history of the disease.
Genes carry the biological information we inherit from our parents. Genes affect the way our bodies grow, work and look.
Many people think that because they have one or two relatives with cancer, this means that a cancer gene is running in their family. But this is not normally the case.
It is only likely that a cancer gene is present in a family if:
Your close relatives are your parents, children, brothers and sisters. They are also sometimes called your first degree relatives.
If your family is like this, and you are worried about developing cancer yourself, you might want to talk to your GP. Your GP will ask you questions about your family history. If they think there’s a chance that you might have an increased risk of developing cancer because of your family history, they will refer you to a genetic counsellor, family cancer clinic or a cancer specialist.
People with a strong family history of some cancers (bowel and breast) are invited to have more regular screening than people who don’t seem at increased risk. Genetic testing is only available for breast, ovarian and bowel cancer. It is normally only possible, if you have a relative with one of these cancers who is willing to be tested first.
It can be a normal reaction to severe illness in the family, or to bereavement, to feel more vulnerable to the same disease. If you can’t stop worrying, you might find it helpful to speak to a counsellor, who can help you get things into perspective. You can ask your GP, or call our nurses on 0808 800 1234, for details of a local service. You could also call the Cancer Counselling Trust to speak to a counsellor.
Mind, the mental health charity, has published a leaflet called 'How to Stop Worrying'.
Other risk factors usually play a more important role in the development of cancer.
The main risk factor for cancer is age. This means that the older you are, the more likely it is that you will develop cancer. Cancer is relatively rare in young people, but relatively common in the old. About 2 out of 3 cases of cancer (65%) happen to people over 65.
Although your age isn’t something you can do anything about, there are other risk factors, known as lifestyle risk factors, that you can control. It has been estimated that about one half (50%) of all cancers diagnosed in the UK could be avoided if people made changes to their lifestyles. These changes don’t mean that you definitely won’t get cancer – but they make it less likely. So here are some things that you might want to consider:
Smoking is the single biggest cause of cancer that can be avoided. In the UK more than a quarter (about 29%) of cancer deaths are caused by smoking. It is responsible for around 9 out of 10 cases of lung cancer (90%), but also plays a role in many other cancers, such as cancer of the mouth, throat, bladder, kidney, pancreas, bowel, stomach and cervix. Breathing other peoples smoke (passive smoking) also increases your risk of developing lung cancer.
If you smoke, giving up is the healthiest decision you can make. If you want help, ask your GP or call the NHS Smoking Helpline.
Not doing enough exercise increases the risk of developing bowel cancer and may increase your risk of breast cancer and some other types too. Exercise seems to regulate the level of hormones and growth factors that are present in your body, which reduces the risk of developing cancer. You don’t need to go to the gym – lots of different forms of exercise, such as walking, cycling or swimming, can be enough if done regularly. The more exercise you do, the lower your risk of developing cancer will be. If you haven’t done a lot of exercise before, your GP can give you advice about getting started.
Being overweight or obese increases your cancer risk, particularly for bowel cancer, breast cancer after the menopause and also for womb (uterine) and kidney cancer. If you are overweight, you have different levels of hormones and growth factors in your blood, which seem to increase your cancer risk.
There are always a lot of stories in the media about how diet may affect cancer risk. However, there is no single food or diet that can guarantee that you won’t get cancer, just as there is no single food that can be blamed for causing it. But it seems that an overall well-balanced diet reduces cancer risk, in particular the risk of developing bowel cancer.
A healthy diet is one that limits the intake of red meat, animal fat and salt, and includes plenty of fibre, fresh fruit and vegetables.
If you or your children are overweight, unsure about your diet or don’t do much exercise, mention your concerns to your GP. Your GP can give you more information or can help you get specialist support.
Sunlight contains radiation (UV rays) which can damage the skin and cause skin cancer. This is particularly the case for fair-skinned, blond and red-haired people.
Protecting yourself and your children from sunburn reduces your cancer risk. Wear loose, cotton clothes that cover your body, and a hat. Use a broad spectrum sun cream that protects against both UVA and UVB rays, with a sun protection factor (SPF) of at least 15. Take extra care with children.
Drinking more than the recommended amount of alcohol increases your cancer risk, especially if you also smoke. In particular, alcohol plays a role in throat and mouth cancer, but it can also increase the risk of bowel and breast cancer.
The European Code Against Cancer recommends that to reduce the risk of developing cancer men should drink no more than two units a day and women no more than one unit a day. A unit is half a pint of ordinary strength beer, lager or cider or one small glass (125ml) of wine or a single measure (25ml) of spirits.
There are some viruses that play a role in the development of some specific cancers. Generally, these viruses are sexually transmitted, but some of them can also be transmitted through blood (for example, if drug users share a needle). Human papillomavirus (HPV) plays a role in many cases of cervical cancer, and may also increase the risk of developing other cancers, such as some head and neck cancers, and cancer of the vulva or penis. Hepatitis B and C can increase the risk of liver cancer, and the HIV (Aids) virus can increase the risk of developing lymphoma and sarcoma (this is rare).
Practising safer sex (by using condoms or other barrier methods of contraception) and not sharing needles, can help to prevent you from contracting these viruses.
This means knowing what is normal for you and what seems a serious change.
The European Code Against Cancer recommends that you should contact your doctor if you have:
You are not wasting your doctor’s time if you mention any of these symptoms to them.
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