Bariatric surgery associated with 61% reduction in malignant melanoma cases

The bariatric surgery reduces the risk of malignant melanoma, a deadly form of skin cancer, by 61%, suggests a study presented at European Congress on Obesity in Vienna, Austria. The researchers also found that the weight loss surgery is also associated with 42% decrease in the risk of skin cancer in general.

The study was conducted by Magdalena Taube and colleagues from the University of Gothenburg, Sweden to analyze the impact of weight loss on melanoma incidence.

Melanoma is a deadly skin cancer, the incidence of which has increased steadily in many countries of the world, especially high-income countries. It develops when the pigment-producing cells (melanocytes) of the skin become cancerous.

Obesity is an established risk factor for cancer and some studies indicate that intentional weight loss sometimes reduces the risk. However, there is a limited evidence for a link between obesity, weight loss, and malignant melanoma. In this study, the authors used data from the matched Swedish Obese Subjects (SOS) study - a prospective controlled intervention trial examining bariatric surgery outcomes.

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 analyze 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.

The authors found that bariatric surgery markedly reduced the risk of melanoma. Over a median follow-up time of 18 years, they observed a 61% reduced risk of malignant melanoma and a 42% reduced risk of skin cancer in general compared to controls given usual obesity care.

The authors conclude: "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."