Most cancers are probably due to a combination of factors

Not everybody who comes into contact with a carcinogen or has an unhealthy lifestyle will develop cancer. For example, not all smokers develop cancer of the lung. In fact, we are all probably exposed to low doses of carcinogens a lot of the time.

The body has certain mechanisms that may protect us from developing cancer. For example, it is thought that many cells that are damaged by carcinogens can repair themselves. Also, the body's immune system may be able to destroy some types of abnormal cells before they multiply into a tumour. Perhaps one carcinogen may only damage one gene, and two or more genes may need to be damaged or altered to trigger the cells to multiply 'out of control'.

In many cases it is likely that a combination of factors such as genetic make-up, exposure to a carcinogen, age, diet, the state of your immune system, etc, play a part to trigger a cell to become abnormal, and allow it to multiply 'out of control' into a cancer.

How is cancer diagnosed?

If a cancer is suspected from your symptoms
Your doctor will examine you to look for abnormalities such as a lump under the skin or an enlarged liver. You may be referred for tests such as X-rays, scans, blood tests, endoscopy, colonoscopy, bronchoscopy, etc, depending on where the suspected cancer is situated. These tests can often find the exact site of a suspected cancer. However, a biopsy is often needed to be certain that the abnormality is a cancer and not something else (such as a benign tumour).

Biopsy
A biopsy is when a small sample of tissue is removed from a part of the body. The sample is then examined under the microscope to look for abnormal cells. Sometimes it is easy to obtain a biopsy. For example, from a lump on the skin which may be a skin cancer. However, it can be difficult to obtain a biopsy from deeper tissues and it may require specialised procedures.

What are the treatment options for cancer?

Treatment options vary, depending on the type of cancer and how far it has grown or spread. See the separate leaflets on the specific cancers for more details. Briefly, the three most common treatments are:

• Surgery. It may be possible to cut out a malignant tumour.
• Chemotherapy. This is a treatment that uses anti-cancer drugs to kill cancer cells, or to stop them from multiplying. There are various different types of drugs used for chemotherapy. The drug or combination of drugs selected depends on the type of cancer being treated.
• Radiotherapy. This is a treatment that uses high energy beams of radiation which are focussed on cancerous tissue. This kills cancer cells, or stops cancer cells from multiplying.

More recently other treatments have been introduced which include:

• Bone marrow transplant. High dose chemotherapy may damage bone marrow cells and lead to blood problems. However, if you receive healthy bone marrow after the chemotherapy then this helps to overcome this problem.
• Hormone therapy. This is where drugs are used to block the effects of hormones. This treatment may be used for cancers that are 'hormone sensitive' such as some cancers of the breast, prostate and uterus.
• Immunotherapy. Some treatments can boost the immune system to help to fight cancer. More specific immunotherapy involves injections of antibodies which aim to attack and destroy certain types of cancer cells. Research is underway to try to find 'vaccines' that would stimulate your own immune system to make antibodies against cancer cells.
• Gene therapy is a new area of possible treatments. Research is underway to find ways of blocking, repairing or replacing abnormal genes in cancer cells.
• Special techniques can sometimes be used to cut off the blood supply to tumours. The tumour then dies.

For some cancers, a combination of two or more treatments may be used. A range of other treatments may also be used to ease cancer related symptoms such as pain.

What are the aims of treatment?

The aims of treatment can vary, depending on the cancer type, size, spread, etc. For example:

• Treatment aims to cure the cancer in many cases. With modern drugs and therapies, many cancers can be cured, particularly if they are treated in the early stages of the disease. (Doctors tend to use the word 'remission' rather than the word 'cured'. Remission means there is no evidence of cancer following treatment. If you are 'in remission', you may be cured. However, in some cases a cancer returns months or years later. This is why doctors are sometimes reluctant to use the word cured.)
• Treatment may aim to control the cancer. If a cure is not realistic, with treatment it is often possible limit the growth or spread of the cancer so that it progresses less rapidly. This may keep you free of symptoms for some time.
• Treatment may aim to ease symptoms in some cases. Even if a cure is not possible, a course of radiotherapy, an operation, or other techniques may be used to reduce the size of a cancer which may ease symptoms such as pain. If a cancer is advanced then you may require treatments such as nutritional supplements, painkillers, or other tecniques to help keep you free of pain or other symptoms.

What is the outlook for people with cancer?

• Some cancers are more 'aggressive' and grow quicker than others.
• Some cancers are more likely to spread to other parts of the body.
• Some cancers respond to treatment better than others.

Therefore, it is not possible give an overall outlook (prognosis). See the information about the individual types of cancer for further details. As a general rule, the outlook is usually better the earlier a cancer is detected and treated.

Some questions you may want to go through with your doctor

If you have been diagnosed with cancer you will have many questions. The organisations listed at the bottom of the leaflet are good sources of further and detailed information. The following are also some suggested questions that you may wish to go over with your doctor.

• What type of cancer have I got?
• How large is it and has it spread to other parts of my body?
• What are the treatment options for this type of cancer?
• What are the risks and possible side-effects of the treatment options?
• How successful is the treatment for my type and stage of cancer? Is the aim of treatment to cure or to control the cancer?

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