Lower Risk for Malignant Melanoma After Bariatric Surgery

January 6, 2020

Bariatric surgery is associated with a distinct reduction in skin cancer risk, according t a study published in JAMA Dermatology.

“This provides further evidence for a connection between obesity and malignant skin cancer, and for the view that we should regard obesity as a risk factor for these forms of cancer,” said Magdalena Taube, MD, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.

The researchers used data from the Swedish Obese Subjects (SOS) study, an ongoing trial taking place at 25 surgical departments and 480 primary healthcare centres in Sweden to examine outcomes after bariatric surgery.

The analysis included patients who underwent gastric bypass (n = 266), banding (n = 376), or vertical banded gastroplasty (n = 1,365). Patients were compared with 2,040 obese individuals who did not undergo bariatric surgery but were receiving treatment for obesity at their primary healthcare centre. All subjects were matched for gender, age, body composition, risk factors for cardiovascular disease, and psychosocial variables.

The SOS study was cross-linked to the Swedish National Cancer Registry, the Cause of Death Registry, and the Registry of the Total Population for data on cancer incidence, death, and emigration.

After a median follow-up time of 18 years, 23 patients in the bariatric surgery group developed any type of malignant skin cancer compared with 45 people in the control group.

The largest risk reduction was seen with malignant melanoma. Of the patients in the bariatric surgery group, 12 were diagnosed with malignant melanoma compared with 29 in the control group. This translates to a 57% reduced risk for malignant melanoma in bariatric surgery group.

The findings support the idea that obesity is a risk factor for malignant skin cancer, including melanoma, and indicate that weight loss in individuals with obesity may reduce their risk for this severe form of cancer.

“We can say this with certainty now, thanks to our having an extremely well documented and described population that we’ve been able to monitor for a long time, and in which we can see very clearly what happens when a major, lasting weight loss takes place,” said Dr. Taube.

Reference: https://jamanetwork.com/journals/jamadermatology/article-abstract/2753269

SOURCE: University of Gothenburg