Weight loss surgery can drastically reduce the risk of deadly skin cancer, a study has found.
Melanoma is a deadly skin cancer, the incidence of which has increased steadily in many countries of the world, especially high-income countries.
Obesity is an established risk factor for cancer and some studies indicate that intentional weight loss sometimes reduces the risk.
However, evidence for a link between obesity, weight loss, and malignant melanoma is limited.
Researchers from University of Gothenburg in Sweden used data from the matched Swedish Obese Subjects (SOS) study - a prospective controlled intervention trial examining bariatric surgery outcomes - to analyse the impact of weight loss on melanoma incidence.
The surgery group consists of 2007 subjects who chose surgical treatment, and the control group consists of 2040 individuals matched for 18 variables including sex, age, anthropometric measurements, cardiovascular risk factors, psychosocial variables, and personality traits.
To analyse malignant melanoma incidence, statistical tests were used to compare time to first melanoma cancer diagnosis between the surgery and control groups. In additional analyses, risk ratios between the surgery and control groups were compared.
Researchers found that bariatric surgery markedly reduced the risk of melanoma. Over a median follow-up time of 18 years, they observed a 61 per cent reduced risk of malignant melanoma and a 42 per cent reduced risk of skin cancer in general compared to controls given usual obesity care.
"In this long-term study, bariatric surgery reduced the risk of malignant melanoma. This finding supports the idea that obesity is a melanoma risk factor, and indicates that weight loss in individuals with obesity can reduce the risk of a deadly form of cancer that has increased steadily in many countries over several decades," researchers said.