New risk for skin cancer survivors
MORE than 10 per cent of those who survive in situ melanoma were at risk of developing another cancer, according to new research by the University of the Sunshine Coast and Cancer Council Queensland.
The study of nearly 40,000 Queensland survivors of in situ melanoma, in which affected tissue remained localised and could be surgically removed, found that 4823 developed another primary cancer (excluding invasive melanoma).
The research has been published in the Journal of Investigative Dermatology, one of the world's top-ranked dermatology journals.
The lead author, and USC's Foundation Professor of Cancer Prevention, Michael Kimlin said the study found survivors had significantly increased risks of developing a range of internal cancers, not necessarily associated with sun exposure.
"In situ melanoma survivors had significantly increased risks of developing lip, thyroid, pancreatic and brain cancers, and decreased risks of head and neck and lung cancers," he said.
"Male in situ survivors, when compared to the regular population, have a significantly increased risk of prostate cancer and female survivors had an increased risk of lip and thyroid cancers and lymphoid leukaemia compared to the regular population."
For those under 50 years old, the overall risk of being diagnosed with another primary cancer (excluding melanoma) increased by 14 per cent, suggesting age at diagnosis was critical. For those over 50, the risk was 5 per cent higher than the general population.
"These findings indicate that in situ melanoma may be associated with the diagnosis of certain second primary cancers, however, we need more research to understand this further," Professor Kimlin said.
He said the findings opened the door for further research.
"What is causing it, we don't know," Prof Kimlin said.
"The next stage is to find out biologically what is going on. Is it sun exposure? Is it levels of Vitamin D absorption? Is it lifestyle factors? Is it medical surveillance? This opens up a whole new set of opportunities for us to help the Australian population live healthier lives."
Professor Kimlin said if a biological cause was established, the findings were likely to change the clinical guidelines for the care of patients after they have had an in situ melanoma removed.
"These people may require increased surveillance as they may be at a higher risk for these other primary cancers, which, when detected early, have good outcomes," he said.
"There are currently limited clinical guidelines for post-procedural care, but this research suggests that there should be more, similar to that which is offered for patients with invasive melanoma."
He said the next step would be to find a way to predict a person's risk of another primary cancer.
"Using this data, we want to now see if we can detect a biomarker in people's blood, taken at melanoma diagnosis, that could help us intervene and treat in future," he said.
Melanoma is the third most common cancer diagnosed in Australia, and in situ melanoma is strongly associated with lifetime sun exposure. The study was conducted using confirmed in situ melanoma cases from 1982 to 2012 in Queensland, which received higher levels of UV radiation than most other areas in the world.
Those concerned about the increased risk should speak with their doctor for advice specific to their condition.