Bariatric surgery reduces risk of skin cancer, finds JAMA study

Sweden: Weight loss surgery or bariatric surgery in obese people reduce the risk of skin cancer, including melanoma, a recent study published in the journal JAMA Dermatology has found.

According to WHO, the incidence of both non-melanoma and melanoma skin cancers has been increasing over the past decades. Currently, between 2 and 3 million non-melanoma skin cancers and 132,000, melanoma skin cancers occur globally each year.

"Obesity has been an established risk factor for many types of cancer and bariatric surgery in patients with obesity is associated with reduced cancer risk. However, the association between obesity and melanoma is inconclusive," wrote the authors.

Magdalena Taube, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden, and colleagues investigated the association of bariatric surgery with skin cancer (squamous cell carcinoma and melanoma) and melanoma incidence.

This nonrandomized controlled trial, the Swedish Obese Subjects (SOS) study, is ongoing at 25 surgical departments and 480 primary health care centres in Sweden and was designed to examine outcomes after bariatric surgery. Patients were enrolled between September 1, 1987, and January 31, 2001. Data analysis was performed from June 29, 2018, to November 22, 2018.

Patients in the surgery group underwent gastric bypass (n = 266), banding (n = 376), or vertical banded gastroplasty (n = 1365). The control group (n = 2040) received the customary treatment for obesity at their primary health care centres.

The study included 4047 participants (mean [SD] age, 47.9 [6.1] years; 2867 [70.8%] female). Information on cancer events was available for 4042 patients.

Key findings of the study include:

• Bariatric surgery was associated with a markedly reduced risk of melanoma (adjusted subhazard ratio, 0.43; median follow-up, 18.1 years) and risk of skin cancer in general (adjusted subhazard ratio, 0.59).


• The skin cancer risk reduction was not associated with baseline body mass index or weight; insulin, glucose, lipid, and creatinine levels; diabetes; blood pressure; alcohol intake; or smoking.

"These findings suggest that melanoma incidence is significantly reduced in patients with obesity after bariatric surgery and may lead to a better understanding of melanoma and preventable risk factors," concluded the authors.

More Information: "Association of Bariatric Surgery With Skin Cancer Incidence in Adults With Obesity: A Nonrandomized Controlled Trial" published in the JAMA Dermatology journal.

DOI: 10.1001/jamadermatol.2019.3240

Journal Information: JAMA Dermatology