LONDON—People who have been treated for a melanoma have more than twice the risk of developing another form of cancer, according to a study published Wednesday.

Lifestyle could play a key role in such cancers, including spending too long in the sun but also smoking and being overweight, it said.

Researchers at Queen's University in Belfast studied almost 21,000 people who had been treated for non-melanoma skin cancer, and over 1,800 who had had melanoma, to see which went on to develop a second primary cancer.

They compared the findings with cancer in people with no history of skin cancer.

A melanoma is the most serious form of skin cancer, with 9,500 cases diagnosed each year and almost 2,000 deaths.

The risk of developing a new cancer after developing non-melanoma skin cancer was 57 percent higher than in the general population, while the risk of developing a new primary cancer after melanoma was more than double.

"This study confirms that people with a diagnosis of skin cancer have an increased future risk of developing another type of cancer," said Liam Murray, one of the authors of the report published in the British Journal of Cancer.

In particular they risked developing another type of skin cancer or a smoking-related cancer, he said, adding: "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," he added.

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 unhealthy lifestyles including excessive sun exposure, he said.

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," she added.

More than 76,500 cases of non-melanoma skin cancer are recorded in Britain each year, but it is estimated that the actual figure could be more than 100,000 as it often goes unreported.