As part of a series on cancer, Dr Paul Brennan, consultant geneticist at Middlesbrough's James Cook University Hospital, explains a new service for those who may be at risk of inheriting the disease.

EARLIER this year, the Teesside Genetics Unit, based at James Cook Hospital, was awarded £300,000 by the Department of Health and Macmillan Cancer Relief to provide a new service to help families affected by cancer. The Teesside Cancer Family History Service, co-ordinated from the unit, covers the whole of the Cancer Care Alliance area, i.e. South Durham, Teesside and part of North Yorkshire.

The idea is to help families where a number of relatives have had cancer, offer them advice about their chance of developing it, and, where necessary, enable them to access surveillance and think about what they can do to help themselves. It is also about the health of entire families and takes the focus away from just looking at individuals in isolation.

To cover a population of over one million, three genetic risk assessment practitioners have been employed to work alongside myself and my team.

The Cancer Family History Service team has provided training for family doctors, practice nurses, hospital doctors and specialist nurses. They are raising awareness of inherited cancers and explaining how the new service can help families affected by cancer. Since its launch in July, the Cancer Family History Team has received over 450 referrals. Once a referral has been made, the team will assess a family's cancer history and assign cancer risks to individuals within the family. Many people worry about getting cancer because cancers have occurred in their family. Cancer is a common illness, affecting about one in three people. The cause of most cancers is not known but risk factors may increase our chances of developing them, such as age, smoking, over exposure to the sun and diet. We now know that about five to ten per cent of cancer is caused by inherited faulty genes. Genes are the biological information you inherit from your parents - they affect the way your body grows and looks.

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 the family if there are several cases of the same type of cancer on the same side of the family, cancers occurring at young ages (before the age of 50) or if there are particular types of cancers that are known to occur together in the same family (e.g. breast and ovarian cancer or bowel and womb cancer).

If you are worried about developing cancer because of your family history, you might want to talk to your doctor or nurse. They will discuss your worries and, if appropriate, refer you to the Cancer Family History Service. For a lot of people, their family history will suggest a low risk of developing cancer. If this is the case, the service will write to you and your doctor/nurse and will not send you an appointment. This is good news for you and your family. If they think that you may be at increased risk, you will be offered an appointment at a clinic close to your home.

At the appointment, the risk assessment practitioners will provide appropriate advice, support and discuss future plans for you and your family, which may involve screening.

Those deemed to be at high risk will be seen by the consultant geneticist or genetic counsellor, where consideration will be given to genetic testing and individual plans for you and your family will be explored. Genetic testing is often not straightforward. Even if the pattern of cancer suggests a strong inherited tendency, the genetic cause needs to be identified. Each family tends to have its own genetic fault. This process can take a long time and is not possible for every family.

We can all help to reduce our chances of developing cancer by following a healthy lifestyle. This involves eating a diet that is high in fruit and vegetables and taking exercise. It is also sensible to avoid things that can cause cancer, such as smoking and over exposure to sunlight and radiation.

Finally, it is important that you should contact your doctor if you notice any of the following:

* A lump anywhere in your body

* Changes in a mole on your skin

* A cough or hoarseness that won't go away after two weeks

* A change in bowel habits lasting more than two weeks

* Unexplained serious weight loss or any abnormal bleeding.

You are not wasting your doctor's time if you mention any of these symptoms to them.