For a study, researchers sought to determine if bariatric surgery is connected with a decreased cancer risk and death in obese people.

Adult patients with a BMI of 35 or above who underwent bariatric surgery in a US health system between 2004 and 2017 were included in the SPLENDID (Surgical Procedures and Long-term Effectiveness in Neoplastic Disease Incidence and Death) matched cohort research. Those who received bariatric surgery were matched 1:5 to patients who did not have obesity surgery for 30,318 patients. The follow-up period concluded in February 2021.

The time to the incidence of obesity-associated cancer (a composite of 13 cancer types as the primary endpoint) and cancer-related death were assessed using multivariable Cox regression analysis. The study comprised 30,318 participants (median age 46 years; median BMI 45; 77% female; and 73% White) with a median follow-up of 6.1 years (IQR, 3.8-8.9 years). At 10 years, the mean between-group difference in body weight was 24.8 kg (95% CI, 24.6-25.1 kg), corresponding to a 19.2% (95% CI, 19.1% -19.4%) higher weight loss in the bariatric surgery group. During the study, 96 individuals in the bariatric surgery group and 780 patients in the nonsurgical control group developed obesity-related cancer (incidence rate of 3.0 events vs. 4.6 events, respectively, per 1,000 person-years). At 10 years, the cumulative incidence of the primary endpoint in the bariatric surgery group was 2.9% (95% CI, 2.2% -3.6%) and 4.9% (95% CI, 4.5%-5.3%) in the nonsurgical control group (absolute risk difference, 2.0% [95% CI, 1.2% -2.7%]; adjusted hazard ratio, 0.68 [95% CI, 0.53-0.87], P=.002). Cancer-related deaths occurred in 21 individuals undergoing bariatric surgery and 205 people undergoing nonsurgical management (incidence rate of 0.6 events vs. 1.2 events per 1,000 person-years). At 10 years, the cumulative incidence of cancer-related mortality in the bariatric surgery group was 0.8% (95% CI, 0.4%-1.2%) and 1.4% (95% CI, 1.1%-1.6%) in the nonsurgical control group (absolute risk difference, 0.6% [95% CI, 0.1% -1.0%]; adjusted hazard ratio, 0.52 [95% CI, 0.31-0.88], P=.01). 

In people with obesity, bariatric surgery was associated with a considerably decreased incidence of obesity-associated cancer and cancer-related death when compared to no surgery.

Reference: jamanetwork.com/journals/jama/article-abstract/2793220