Why do cancers come back?
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, often referred to as a ``secondary`` or a ``metastasis``.
How is it treated?
There are five main types of treatment for cancer and these are described below:-
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.
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 not 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.
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 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 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.
Other treatments can be used to cure or control a cancer. These include chemicals which stimulate the body's immune system to attack the cancer cells. They are called biological therapies and include interferon and interleukin.
Monoclonal antibodies are drugs that can `recognise' and find specific cells in the body. These drugs can be designed to find a particular type of cancer cell, attach itself to them and destroy them. They can be used alone, or a radioactive molecule can be attached to a monoclonal antibody, which then delivers radiation directly to the cancer cells.
Research is trying to see whether vaccines 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.
Diet and lifestyle
There are over 200 different types of cancer. We donít know the causes for each one of these cancers, but we do know about some. It is important to note that for many cancers, there may be more than one cause. One of the biggest risks is increasing age. Cancer can occur at any age but the risk of developing it increases with age; over 70% of people who get cancer are over the age of 60.
We make lifestyle choices everyday; some we know increase our risk of developing cancer, others may have an influence on our risk. For example, smoking is a major cause of lung cancer and is a factor in other cancers, such as bladder cancer and cancers of the mouth and throat.
Other factors are heavy alcohol consumption and exposure to sunlight.
In this section, there are a number of questions and answers about diet and lifestyle as causes of cancer. You may also find it helpful to look in our section about diet and the cancer patient, for further information on healthy diets.
Enviromental & occupational
A carcinogen is something that causes cancer. Contact with certain harmful substances in the workplace can cause cancer.
We know, for example, that 9 out of 10 people who develop mesothelioma (a rare type of cancer affecting the linings of the lung and abdomen) have had contact with asbestos. People who have worked in industries such as ship- building and construction may have come into contact with asbestos. Its use is now banned in this country. For further information about this type of cancer look in our Mesothelioma information centre.
Another example is exposure to certain chemicals in the workplace; those used in dye factories, rubber, gas works and other chemical industries have all been linked to bladder cancer. These chemicals have now been banned. See our bladder cancer information centre for further information about this type of cancer.
Environmental causes include natural radiation, for example, from the sun. We know that most skin cancers are caused because of prolonged exposure to the sun.
It is important to remember that we donít know the cause of many cancers and that there is often more than one cause. Also, although cancer can occur at any age, one of the biggest risks of it developing is increasing age.
In this section, there are a number of questions and answers about environmental and occupational causes of cancer.
Cancer genetics - how cancer sometimes runs in families
This section is for anybody who is worried that cancer might run in his or her family. It is also for people who have been advised, or who have decided, to see a cancer genetics specialist or genetic counsellor. If you don't have at least two relatives with the same type of cancer on the same side of your family, the information in this section is probably not relevant to you.
Many people ask themselves why cancer has happened to them or to a close relative. People often feel that cancer is such an awful disease that they want to know why they developed it. They might think about their own medical history or about risks in the environment. People sometimes also think that several cases of cancer in their family might be connected, and that they have inherited an increased cancer risk. However, only a small minority (5-10%, or less than 10 out of 100 cases) of cancers are clearly linked to an inherited gene change. Unfortunately, most cancers happen for reasons we don't fully understand.
Cancer is a common disease. It is estimated that in the UK about 1 in 3 people will get cancer during their lives. Most people who get cancer are over 65. It is relatively rare for young people (people under 50) to get cancer. If you have only one elderly relative with cancer, you are not at a significantly increased risk of getting the same cancer yourself.
This section outlines our current understanding of how specific genes are sometimes involved in the development of some cancers. It describes how cancer genetic services (also called familial cancer services) are provided by the NHS. It explains some of the science and the practice of genetic testing and addresses the questions you might have about genetic tests.
Not all parts of this information will be equally relevant to everyone. The menu on the left hand side can help you find the information that is useful for you. Some key information is repeated in several sections to ensure that anyone dipping into the section sees the information in context.
If you think this section has helped you, do pass it on to any of your family and friends who might want to have this information.
It is important to remember cancers are not infectious and cannot be caught from someone. However, there are a number of different viruses that are thought to be contributing factors in the development of cancer.
For example, exposure to HPV (human papilloma virus) is known to increase a womanís risk of developing cancer of the cervix. For further information about this, see CancerBACUP's section about HPV.
Other viruses include the Epstein-Barr virus, which is linked to some types of lymphoma.
There is also a bacterial infection known as H-pylori which is linked to a rare type of stomach cancer.
How is cancer diagnosed?
Most people experience symptoms and begin by seeing their GP. If your GP thinks that you have symptoms that may be caused by cancer, s/he will examine you and refer you on to a specialist at the hospital for tests and treatment, if necessary.
At the hospital, the doctor will take your medical history and do a physical examination. You may have x-rays and blood tests taken and possibly scans. You may need to have a sample taken of the lump or abnormal area Ė this is known as a biopsy. The biopsy sample is then analysed in a laboratory and the cells examined so that the doctors can see exactly what type of cancer it is and whether it is likely to grow slowly or more quickly.
Scans can measure the size of the cancer and whether it has spread to other tissues or nearby lymph glands (nodes). This process is called ``staging`` the cancer. Once the type and stage of the cancer is known, the doctors can decide how best to treat it