What is cancer?
The organs and tissues of the body are made up of tiny building blocks called cells. Cancer is a disease of these cells.
Cells in different parts of the body may look and work differently but most reproduce themselves in the same way. Cells are constantly becoming old and dying, and new cells are produced to replace them. Normally, cells divide in an orderly and controlled manner. If for some reason the process gets out of control, the cells carry on dividing, developing into a lump which is called a tumour
Tumours can be either benign or malignant. Cancer is the name given to a malignant tumour. Doctors can tell if a tumour is benign or malignant by examining a small sample of cells under a microscope. This is called a biopsy.
In a benign tumour the cells do not spread to other parts of the body and so are not cancerous. However, if they continue to grow at the original site, they may cause a problem by pressing on the surrounding organs.
A malignant tumour consists of cancer cells that have the ability to spread beyond the original area. If the tumour is left untreated, it may spread into and destroy surrounding tissue. Sometimes cells break away from the original (primary) cancer. They may spread to other organs in the body through the bloodstream or lymphatic system.
The lymphatic system is part of the immune system - the body's natural defence against infection and disease. It is a complex system made up of organs, such as bone marrow, the thymus, the spleen, and lymph nodes. The lymph nodes (or glands) throughout the body are connected by a network of tiny lymphatic ducts.
When the cancer cells reach a new area they may go on dividing and form a new tumour. This is known as a secondary cancer or metastasis.
It is important to realise that cancer is not a single disease with a single type of treatment. There are more than 200 different kinds of cancer, each with its own name and treatment.
Types of cancer
Carcinomas
The majority of cancers, about 85% (85 in a 100), are carcinomas. They start in the epithelium, which is the covering (or lining) of organs and of the body (the skin). The common forms of breast, lung, prostate and bowel cancer are all carcinomas.
Carcinomas are named after the type of epithelial cell that they started in and the part of the body that is affected. There are four different types of epithelial cells:
squamous cells - that line different parts of the body, such as the mouth, gullet (oesophagus), and the airwaysadeno cells - form the lining of all the glands in the body and can be found in organs such as the stomach, ovaries, kidneys and prostatetransitional cells - are only found in the lining of the bladder and parts of the urinary systembasal cells - that are found in one of the layers of the skin.A cancer that starts in squamous cells is called a squamous cell carcinoma. A cancer that starts in glandular cells is called an adenocarcinoma. Cancers that start in transitional cells are transitional cell carcinomas, and those that start in basal cells are basal cell carcinomas.
Leukaemias and lymphomas
These occur in the tissues where white blood cells (which fight infection in the body) are formed, i.e. the bone marrow and lymphatic system. Leukaemia and lymphoma are quite rare and make up about 6.5% (6.5 in 100) of all cancers.
Sarcomas
Sarcomas are very rare. They are a group of cancers that form in the connective or supportive tissues of the body such as muscle, bone and fatty tissue. They account for less than 1% (1 in 100) of cancers.
Sarcomas are split into two main types:
bone sarcomas - that are found in the bonessoft tissue sarcomas - that develop in the other supportive tissues of the body.
Signs and symptoms of cancer
Cancer can often be managed more easily when it is diagnosed in the early stages. Being aware of your body and what is 'normal' for you, and reporting symptoms to your GP, can help to make sure that, if you do have cancer, it is diagnosed as early as possible.
There are some common signs and symptoms that may alert you to the fact that something is new or different. You should contact your doctor if you have any of the following:
Lumps
Coughing, breathlessness and hoarseness
Changes in bowel habit
Bleeding
Moles
Unexplained weight loss
What to do if you have worrying symptoms
References
Lumps
Knowing how your body normally looks and feels can help you spot any early changes that could be caused by cancer. You should see your GP if you notice a lump anywhere in your body. It can be useful to tell them how long it’s been there and whether it is getting bigger, or causes discomfort. Cancerous lumps are often (but not always) painless.
It can be difficult to tell what a lump is just by feeling it, but if your GP suspects that you might have a cancer they will refer you to the appropriate specialist for further tests.
It is important to remember that lumps and bumps often occur in the body, and most of these will not be cancer.
Coughing, breathlessness and hoarseness
There are many medical conditions that can cause 'chesty' symptoms like coughing and breathlessness (for example, infections and inflammations), but in some cases these symptoms may be a sign of lung cancer. If you have a cough or feel breathless for more than two weeks you should see your GP. You should also tell your GP if you have any blood in your sputum (phlegm) when you cough.
Laryngitis (inflammation of the larynx) is common and can cause a hoarse voice. In a small number of people, a hoarse voice may be a sign of cancer of the larynx (voice box). If hoarseness continues for longer than two weeks, you should tell your GP.
Changes in bowel habit
Symptoms of bowel cancer may include blood in your stools (bowel motion). The blood would usually be dark but can be bright red in colour. Fresh, bright red blood is usually a sign of piles (haemorrhoids).
You may notice a change in your normal bowel pattern (such as diarrhoea or constipation) for no obvious reason. You might have a feeling of not having emptied your bowel properly after a bowel motion. Some people also notice that they have pain in the abdomen or back passage.
Remember that altered bowel habits aren't always caused by cancer, but can be caused by changes in diet, some medicines, anxiety, and other medical conditions. If any changes last for more than a few weeks it's important to rule out cancer as a possible cause, so you should see your GP.
Bleeding
Any unexplained bleeding is a sign that there is something wrong and should always be checked out by your GP.
As previously mentioned, bleeding from the back passage is most commonly caused by piles, but can sometimes be due to cancer of the bowel or rectum.
Cancer of the womb or cervix can cause women to bleed between periods or after ***. Women who have any vaginal bleeding after they have had their menopause should see their GP. If necessary your GP will refer you to a gynaecologist.
Blood in your urine may be caused by bladder or kidney cancer. It can also be caused by infection. If you notice blood in your urine it is important to see your GP for a check-up. (It may be helpful to know that the colouring in some medicines or food can cause urine to look pink, as can natural foods, such as beetroot.)
Coughing up blood in your sputum may be caused by serious chest infections, but can sometimes be a sign of lung cancer.
Vomiting blood can be a sign of stomach cancer, although it can also be due to a stomach ulcer. Therefore, it is important to have this checked out by your GP.
Bruising and nosebleeds are rarely signs of cancer, but can in some cases be caused by leukaemia. However, people with leukaemia often have other troublesome symptoms too.
Moles
Malignant melanoma is a type of skin cancer that often starts with a change in the appearance of normal skin. This can look like an abnormal new mole. Less than a third of melanomas develop in existing moles. It can be difficult to tell the difference between a mole and a melanoma, but any of the following changes should be checked out:
Asymmetry Moles are usually regular and symmetrical in shape. Melanomas are likely to be irregular or asymmetrical.
Border Moles usually have a well-defined regular border. Melanomas are more likely to have an irregular border with jagged edges.
Colour Moles tend to be a single brown. Melanomas often have more than one colour. They may be varying shades of brown mixed with black, red, pink, white or a bluish tint.
Size Moles are normally no bigger than the blunt end of a pencil (about 6mm (½ inch) across). Melanomas are usually more than 7mm (½ inch) in diameter.
Itching, crusting or bleeding may also occur in melanomas – these are less common signs but should not be ignored.
It is important to see your GP if you have any unusual marks on the skin that last more than a few weeks, or an existing mole which shows any of the above signs. If necessary they will arrange for you to see a doctor who specialises in skin conditions (a dermatologist) or a surgeon.
Unexplained weight loss
If you have lost a lot of weight over a short period of time (a couple of months), that cannot be explained by changes in your diet, increased exercise or stress, it is important to tell your GP. Other symptoms, such as sickness, pain and fatigue also tend to occur when a person experiences weight loss due to cancer.
What to do if you have worrying symptoms
You usually begin by seeing your GP who will examine you, ask questions about your symptoms, and might ask you to have some tests, such as a blood test or x-ray.
If your GP suspects that you may have cancer, an urgent referral will be made to a specialist. There are guidelines produced by the National Institute for Health and Clinical Excellence (NICE) to help GPs identify when symptoms could be due to cancer or some other condition. An urgent referral usually means that the specialist will see you within two weeks. The specialist can carry out other investigations, such as a biopsy or various scans, to find the cause of your symptoms and plan any treatment necessary.
If your GP thinks your symptoms are not caused by cancer they may still refer you to a specialist for advice, but the referral is likely to be non-urgent and it will take longer for you to be seen.
Remember – in most cases, your symptoms will turn out to be caused by something other than cancer, but they can still be signs of illness and so you won't be wasting your doctor's time by getting them checked out.
Who gets cancer?
Each year more than a quarter of a million people are diagnosed with cancer in the UK, and 1 in 3 people will develop cancer during their lifetime. But cancer is not common in children or young people - it mainly occurs in the later years of life. Cancers can occur at any age, but the risk of developing cancer increases with age. 64% (64 in 100) of all newly diagnosed cancers occur in people aged 65 years or more. Less than 1% (1 in 100) of cancers are diagnosed in children, aged 0-14 years.
Some cancers are very common and others are very rare. The most recent statistics for the UK (from 2003) show that for men the most common cancer is prostate cancer (23%), followed by lung cancer (16%), large bowel cancer (14%) and bladder cancer (5%).
For women the figures are breast cancer (31%), large bowel cancer (11%), lung cancer (11%) and cancer of the ovary (5%).
Many people with cancer can be cured. Even if a cancer cannot be cured, it can often be controlled with treatment for months or years.
Cancerbackup has information on all the main types of cancer, and on some of the rarer cancers.
How is it treated?
There are six main types of treatment for cancer and these are described below. It is fairly common for a combination of treatments to be used.
Active surveillance (or watchful waiting)
Some types of cancer grow very slowly and may cause no problems for many years. In this situation you may not need to have any treatment for some time, but your doctor will monitor you closely so that if the cancer does start to grow you can be given treatment at that time.
Surgery
An operation is done to remove the tumour. Surgery is often used if the cancer is only in one area of the body and has not spread. It may be used to remove lymph nodes if these are also affected by the cancer. It can sometimes be used to remove a cancer that has spread to another area of the body, but this is less common. The type of operation will depend on the area of the body affected by the cancer, and on the size and position of the tumour.
Radiotherapy
This is the use of high energy x-rays to destroy cancer cells, but cause as little harm as possible to normal cells. The radiotherapy is aimed at the affected area of the body and is very carefully planned. It can cause side effects and the most common is tiredness. The side effects will depend on the part of the body that is being treated.
Chemotherapy
Chemotherapy is the use of anti-cancer (cytotoxic) drugs to destroy cancer cells. There are more than 50 different chemotherapy drugs. Some are given as tablets or capsules but most are given by drip (infusion) into a vein. The drugs go into the bloodstream and travel throughout the body to treat the cancer cells wherever they are. Sometimes just one chemotherapy drug is used, but often a combination of two, three or more drugs is given.
Chemotherapy can cause side effects. The side effects will depend on which drug (or combination of drugs) is used. There are now very good ways of preventing or reducing the side effects of chemotherapy.
Hormonal therapy
Hormonal therapies work by altering the levels of particular hormones in the body. Some cancers depend on certain hormones in order to divide and grow. By altering the level of hormones in the body, or blocking the hormones from attaching to the cancer cells the cancer can be controlled.
Biological therapy
Biological therapies use substances that occur naturally in the body to destroy cancer cells. There are several types of biological therapy, including: monoclonal antibodies, cancer growth inhibitors, vaccines and gene therapy.
Monoclonal antibodies are drugs that can 'recognise' and find specific cells in the body. They can be designed to find a particular type of cancer cell, attach itself to them and destroy them. They can also carry a radioactive molecule, which then delivers radiation directly to the cancer cells.
Cancer growth inhibitors interfere with the way cancer cells use 'chemical messengers' to help the cell to develop and divide.
Research is trying to see whether vaccines and gene therapy can be given to treat a cancer that has come back or has spread. Vaccines may also be able to reduce the chance of a cancer coming back, but this type of research is in the very early stages.
Cancerbackup has information on all the cancer treatments mentioned above and also on cancer research trials.
Why do cancers come back?
In some cases cancer can come back after treatment. It may come back in the same area in which it first started, this is known as a recurrence. This can happen because tiny cancer cells, that may have been left behind when the tumour was removed, or that weren't destroyed by treatments such as radiotherapy and chemotherapy, have begun to divide again and form a tumour.
Or it may develop in a different part of the body, often referred to as a metastasis or secondary cancer. This can happen because a cancerous (malignant) tumour consists of cancer cells which have the ability to spread beyond the original site. If left untreated they may invade and destroy surrounding tissues. Sometimes cells break away from the original (primary) cancer and spread to other organs in the body by travelling in the bloodstream or lymphatic system. When these cells reach a new area of the body they may go on dividing and form a new tumour.
14-07-2007, 11:16 PM
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