Researchers studying nearly 23,000 cases of people treated for skin cancer found that melanoma, the most severe form, was linked to double the risk of having another primary cancer and less severe skin cancers were also linked to further primary cancers but the risks were lower than after melanoma.
The study was the work of scientists in Northern Ireland and France, and is published in the 6 January online issue of the British Journal of Cancer.
Malignant melanoma, also known as melanoma, is the most serious of the skin cancers. In the UK more than 9,500 people are diagnosed with it and 2,000 die every year. The incidence for non-melanoma skin cancers, which includes basal cell carcinoma (BCC) and squamous cell carcinoma (SCC), is more than 76,500 in the UK every year. This is according to registered cases, but estimates put the figure as high as 100,000 because this type of cancer is not always reported.
The researchers studied 14,500 cases of BCC, 6,405 cases of SCC and 1,839 cases of melanoma reported between 1993 and 2002 to the Northern Ireland Cancer Registry. They looked for patients that went on to develop a second primary cancer and compared them to the incidence of cancer in the general population.
They found that compared to the general population, the risk of a new cancer was more than double after melanoma, and between 9 and 57 per cent for BCC and SCC respectively. The people who had been diagnosed with non-melanoma skin cancer had nearly double the risk of developing melanoma and a higher risk of developing a smoking-related cancer.
One of the authors of the study, Professor Liam Murray of Queen’s University Belfast, said in a statement:
“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.”
Speculating on possible explanations he said sun exposure was an important risk factor for all types of skin cancer, so patients who have one are perhaps more likely to go on and develop another. Another reason might also be that a new skin cancer is more likely to be spotted in patients that are already under observation following treatment for skin cancer.
Murray also suggested a reason for the smoking-related cancers might 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”.
Sarah Hiom, director of health information at Cancer Research UK said:
“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.”
“We know that lifestyle factors such as excessive UV exposure, smoking, being overweight and drinking too much alcohol can increase the risk of cancer,” she said.
“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,” warned Hiom.
She said it was important to note that about two thirds of melanomas and 90 per cent of non-melanoma skin cancers come from UV exposure. Even using a sunbed once a month or more increases the risk of skin cancer by more than half, and using one before the age of 35 increases the risk of having melanoma by up to 75 per cent.
“Second primary cancers in patients with skin cancer: a population-based study in Northern Ireland.”
M M Cantwell, L J Murray, D Catney, D Donnelly, P Autier, M Boniol, C Fox, R J Middleton, O M Dolan, A T Gavin.
British Journal of Cancer 100, 174 – 177, published online 06 Jan 2009.
doi: 10.1038/sj.bjc.6604842
Sources: Queen’s University Belfast.
Written by: Catharine Paddock, PhD