Skin cancer ups risk of mouth cancer

People who have been treated for skin cancer have an increased risk of developing a new primary cancer, especially a smoking-related one such as mouth cancer, according to a Queen’s University study.

Researchers analysed information held by the Northern Ireland Cancer Registry (NICR) at Queen’s between 1993 and 2002. They studied almost 21,000 people who had been treated with non-melanoma skin cancer and just over 1,800 people who had had melanoma, to observe how many of them 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.

The research 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%.

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 times more likely to go on to develop melanoma and had an increased risk of smoking-related cancers.

Queen’s Professor Liam Murray, one of the authors of the report, which was published in the British Journal of Cancer, 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.’