Obesity surgery reduces melanoma risk
New research from Sweden presented at the recent European Congress on Obesity, shows that bariatric surgery is associated with a 61% fall in the risk of developing malignant melanoma skin cancer, and a 42% drop in the risk of skin cancer in general.
The incidence of malignant melanoma has increased steadily in many countries of the world, especially high-income countries. For example, in the UK, cases have more than doubled since the 1990s, and it is the fifth most common cancer in men and women, with over 15,000 cases each year and more than 2000 deaths (Cancer Research UK website).
Although obesity is an established risk factor for cancer, evidence for a link between obesity, weight loss, and malignant melanoma is limited. In this study, the authors 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).
The authors found that bariatric surgery reduced the risk of melanoma by 61% over a median follow-up time of 18 years and the risk of skin cancer in general by 42% compared to controls given usual obesity care. They concluded that "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."
- Reduced risk of malignant melanoma (HR = 0.39; 95% CI 0.20–0.78; p = 0.008)
- Reduced risk of skin cancer in general (HR = 0.58; 95% CI 0.34–0.99; p = 0.044).
- Median follow-up 18.1 years (interquartile range 14.8–20.9 years)
The study supports the idea that obesity is a melanoma risk factor, and indicates that weight loss in individuals with obesity can reduce the risk of this deadly form of cancer that has increased steadily in many countries over several decades. This provides another good reason for healthcare professionals to encourage obese patients to reduce weight.
Taube M et al. Bariatric surgery reduces malignant melanoma incidence in the Swedish Obese Subjects study. Oral presentation O7.6 at the European Congress on Obesity, 23-26 May 2018.