Skin cancer puts people at higher risk of new cancer

14 January 2009

People who have been treated for skin cancer have an increased risk of developing a new primary cancer according to a study published in the British Journal of Cancer.

Researchers analysed information held on the Northern Ireland Cancer Registry (NICR) between 1993-2002. They studied 20,823 people who had been treated with non-melanoma skin cancer and 1,837 people who had had melanoma to observe how many of these people went on to develop a second primary cancer. They compared this data with the incidence of cancer in people with no history of skin cancer.

They found that compared with the general population, the chance of people developing a new primary cancer after they had developed non-melanoma skin cancer was increased by up to 57 per cent – and the risk was much higher in those who had had squamous cell carcinoma (SCC) than those who had basal cell carcinoma (BCC). The subsequent risk of developing a new primary cancer after melanoma was more than double.

People who had been diagnosed with non-melanoma skin cancer were almost two-fold more likely to go on to develop melanoma and had an increased risk of smoking-related cancers. Malignant melanoma, also known as melanoma, is the most serious type of skin cancer with more than 9,500 new cases diagnosed in the UK each year and almost 2,000 deaths.

There are more than 76,500 cases of non-melanoma skin cancer registered in the UK each year. It is estimated that the actual figure could be at least 100,000 because this type of cancer can go unreported. There are two types – basal cell carcinoma and squamous cell carcinoma.

Professor Liam Murray, a study author based at Queen's University Belfast, said: "This study confirms that people with a diagnosis of skin cancer have an increased future risk of developing another type of cancer, especially one of the other types of skin cancer or a smoking related cancer – and for those with melanoma the risk may be more than double that of the rest of the population.

"There are several possible explanations for this link. Sun exposure is an important risk factor for all types of skin cancers so patients who have had one type of skin cancer may be more likely to develop other types as well. Alternatively a new skin cancer may be more likely to be detected in patients who are monitored following their first diagnosis of skin cancer.

"The increase in smoking-related cancers may be because smoking predisposes to skin cancer as well as other cancers or because people who smoke may be more likely to have generally unhealthy lifestyles including excessive sun exposure."

Sara Hiom, Cancer Research UK’s director of health information, said: "We know that lifestyle factors such as excessive UV exposure, smoking, being overweight and drinking too much alcohol can increase the risk of cancer.

"These important findings could help doctors target health information more accurately to people who have been treated for skin cancer to help them reduce their risk of developing a second cancer.

"It's important to remember that around two-thirds of melanomas and 90 per cent of non-melanoma skin cancers are caused by UV exposure and using a sunbed once a month or more, can increase risk of skin cancer by more than half. Using sunbeds before the age of 35 increases risk of developing melanoma skin cancer by up to 75 per cent.

"Avoiding excessive exposure to UV can dramatically reduce a person’s risk of developing skin cancer in the first place. Winter sun seekers in search of a fast tan boost should remember to cover up, to use factor 15 plus sun cream and avoid the midday sun to prevent burning, as well as reduce the risk of developing a second cancer."

(Source: British Journal of Cancer: Cancer Research UK: January 2009)