New results from the on-going Swedish Obese Subjects (SOS) study suggest bariatric surgery in individuals with obesity is associated with a reduced risk of skin cancer, including melanoma.
The non-randomised SOS study was designed to examine outcomes after bariatric surgery and is continuing at 25 surgical departments and 480 primary healthcare centres in Sweden. Patients were recruited to the study between 1 September 1987 and 31 January 2001.
This latest analysis included 2,007 patients with obesity who underwent bariatric surgery and 2,040 matched controls who received conventional obesity treatment.
The authors found that bariatric surgery was associated with a reduced risk of melanoma (adjusted sub-hazard ratio 0.43; 95% CI 0.21-0.87; P=.02) and risk of skin cancer in general (adjusted sub-hazard ratio 0.59; 95% CI 0.35-0.99; P=.047). The number needed to treat to prevent one malignant melanoma event over 20 years with bariatric surgery was 106.
Writing in JAMA Dermatology, the authors said the findings give additional support for an association between obesity and skin cancer and for an association between weight loss and reduced cancer incidence.