What is Cancer?
Cancer is the name for a group of diseases where individual cells become abnormal, dividing and growing to form tumours. There are over 200 different types of cancer arising from cells in different parts of the body. Some cancers invade nearby organs or spread through the bloodstream and lymphatic system to other parts of the body, forming secondary tumours also known as metastases. Both benign (non-cancerous) and malignant tumours (cancers) can cause symptoms by pressing on other structures in the body.
Some tumours grow very slowly whilst others increase in size more rapidly. Response to treatment, usually radiotherapy, surgery, chemotherapy or a combination of these, also varies. Many cancers can be cured, but even if this is not possible modern treatments can improve the quality of life for the vast majority of patients.
This information on this website focuses on the cancers where radiotherapy is used in treatment.
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What is the Difference between Benign and Malignant Tumours?
Benign tumours are collections of cells that are non-cancerous. They may cause symptoms by pressing on other parts of the body but generally they grow slowly and do not spread to other parts of the body. If they can be removed by surgery, any problem they cause can usually be cured.
Malignant tumours are made up of cancer cells that tend to grow more rapidly than benign tumours and usually spread into neighbouring tissues and organs, and often by the blood and lymphatic systems to other parts of the body to form secondary tumours, called metastases.
In general, cancers or malignant tumours are treated actively, but even in some cancers the tumour poses no immediate problem so that regular review is all that is required.
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How Common is Cancer?
Approximately 3 million people in Europe develop cancer every year. Approximately 1 in 3 of all people will develop a cancer during their lifetime. So, overall, cancer is common, but some types occur more frequently than others – breast, lung, bowel (colon and rectum) and prostate cancer account for over half of all newly diagnosed cancers. Other common cancers include oesophagus (gullet), tumours of the head and neck, uterus (womb), the lymphomas, brain tumours and other cancers of the nervous system and leukaemia.
The ‘incidence’ of cancer (means the number of new cases each year, and this is usually expressed as the number of new cases for every 100,000 people. For example, in the UK, the incidence of cancer in men is approximately 490 per 100,000, and for women, slightly less at 463 per 100,000. Across Europe there are variations from country to country.
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What Causes Cancer?
There is no single cause for the many different types of cancer. In general, cancer is more common in older people because of the changes in cell genes that occur with age. These genes control the way cells grow and divide, so if they are damaged, the cells can become malignant. These changes can be accidental when cells are dividing or caused by chemicals called carcinogens.
Smoking is associated with lung cancer and bladder cancer but not everyone who smokes will develop these conditions. Other contributory factors include age and your genetic make up.
Some cancers, for example, cancer of the cervix and some lymphomas, are caused by viruses.
Diet is also linked with cancer. Western diets high in animal fats and comparatively low in fruit and vegetables are more commonly associated with a higher incidence of cancer.
Obesity is another risk factor, particularly for uterine cancer in women and prostate cancer in men, and to a lesser extent bowel, oesophageal and kidney cancer in both sexes, probably due to the hormonal effects associated with higher levels of fat in the body.
People who eat large amounts of red and processed meat are more liable to develop stomach and bowel cancer and there is evidence that meat cooked at high temperatures may increase the risk of developing some cancers.
Alcohol increases the risk of mouth, throat, and oesophageal cancers especially in smokers, as well as liver, breast and bowel cancers.
A number of other diseases are also linked with a higher risk of cancer for example ulcerative colitis is linked with colon cancer, and exposure to the sun increases the risk of skin cancer.
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Can Cancer be Prevented?
There is no certain way of preventing all the forms of cancer but there are many aspects of lifestyle and diet that can affect the risk of cancer, so changes can be made to reduce the risk.
Giving up smoking, eating a healthy diet, reducing obesity and only consuming alcohol in moderation will all reduce the risk of a variety of cancers.
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Does Cancer Run in Families?
Some families do have a much higher incidence of cancer than the general population. This might be from a specific form of cancer, for example breast or bowel cancer, or for all cancers.
With prostate cancer, several sites on the human genome have been identified as being associated with the development of prostate cancer, which means that men with these genetic risk factors are predisposed to developing the disease. Other genetic markers also exist for other forms of cancer, but as yet routine tests for these markers have not been developed.
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What is the Link between Smoking and Cancer?
Smoking is the single most preventable contributory cause of death in the Western world, and is associated with approximately 30% of all cancer deaths in the United States.
Smoking is a major contributory factor in about 80% of lung cancer deaths, the commonest cause of death from cancer in both men and women. In addition, smoking is the major risk factor for cancers of the larynx, mouth, oesophagus and bladder as well as being linked to kidney, pancreatic, cervical and stomach cancer and chronic myeloid leukaemia.
Passive or secondary smoking significantly increases the risk of lung cancer in non-smokers, and there are thought to be more than 60 carcinogens in cigarette smoke.
Consequently, giving up smoking is one of the most important measures anyone can take to reduce their risk of cancer and many other diseases.
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What is the Link between Diet and Cancer?
As many as 25% of all cancer deaths are probably due to unhealthy diets and obesity.
Cancer deaths, particularly from bowel, stomach, mouth, oesophageal and breast cancer, can be reduced by eating a balanced diet that is high in fibre, fruit and vegetables and low in red and processed meat, and saturated fats.
Eating the recommended 5 portions of fruit and vegetables each day, controlling the quantities of processed meat and saturated fat, watching your weight and exercising reduces the risk of cancer.
In addition, some foodstuffs such as broccoli are known to have protective effects. For example, Vitamins D and E, selenium and lycopene (found in tomatoes) may offer protection against prostate cancer, while a high-fibre/low-fat diet may help to prevent bowel cancer.
There are a number of anti-cancer diets which are meant to prevent cancer but there is no scientific evidence that some of these diets work, and some exclude whole groups of foods and may therefore expose you to further health risks.
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What is the Link between Alcohol and Cancer?
Alcohol consumption (two 125ml glasses of wine or equivalent per day for men and one 125ml glass or equivalent per day for women) increases the risk of developing cancer of the parts of the body that come into contact with alcoholic drinks, i.e. the mouth, pharynx, oesophagus and larynx, especially in smokers. Alcohol also increases the risk of liver cancer and breast cancer in women. Heavy drinkers also have a higher risk of bowel cancer.
However, red wine is a source of polyphenols, which are believed to have antioxidant properties and inhibit cancer growth.
All alcoholic drinks, including red wine, should be consumed in moderation to avoid a higher risk of the cancers mentioned above.
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How is Cancer Diagnosed?
Cancer is diagnosed in a variety of ways but all too often it is diagnosed too late in the progression of the disease. Generally, the earlier cancer is diagnosed, the better the chances of effective treatment, including cure of the disease, so any symptoms suggestive of any form of cancer should be reported and investigated without delay.
Some cancers are diagnosed using screening tests – the cervical smear programme for cervical cancer and the prostate specific antigen (PSA) test for prostatic cancer are two examples, but more frequently cancers are diagnosed after patients report symptoms to their doctors.
Patients at particular risk of certain forms of cancer may be offered other screening tests. For example, those with a strong family history of bowel cancer may be offered colonoscopy and patients with bowel polyps are likely to need regular colonoscopy and polyps removal.
The presenting symptoms will vary from cancer to cancer but few symptoms are unique to any form of cancer. A physical examination and further tests are usually necessary. In some cases, taking a sample for laboratory examination is essential to clarify the exact nature of the cancer and this in turn determines the required treatment.
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What are the Symptoms of Cancer?
The symptoms of cancer vary according to the site of origin, the part of the body it may spread to and its effects on the body’s metabolism and other effects such as pressure on other structures in the body.
For further information on the specific cancers, you can refer to the appropriate section of this website.
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Can Cancer be Cured?
Yes, cancer can be cured. Continuous advances in radiotherapy and other cancer treatments improve patient outcomes year on year.
When discussing treatments and outcomes amongst themselves, healthcare professionals tend not to talk about cure rates but survival rates at a particular point in time. A survival rate is the percentage of patients with a particular type of cancer who live for 5 or 10 years after diagnosis. But these are only averages and not particularly meaningful when looking at individual patients whose outlook will depend upon a number of factors unique to them.
The best person to advise on your prognosis is always your own doctor who will be able to consider all the relevant factors.
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How is Cancer Treated?
Cancer is treated in a number of ways including radiotherapy, surgery and chemotherapy (treatment with drugs). Often a combination of these techniques will be used – sometimes referred to as multimodality treatment.
The primary aim of treatment is to eradicate the cancer but even when this is not possible treatment can be very effective and add enormously to the quality of life.
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