Background

The objective of this study was to compare the incidence of new cancer diagnoses, types of cancer at diagnosis, overall survival, and disease-free survival between bariatric surgical patients and obese patients not undergoing bariatric surgery. Methods: This study is a retrospective cohort study that compared (1) bariatric surgical patients, September 2001 - December 2019, and (2) the control population. The control population included non-surgical obese patients (BMI >30 kg/m2) matched by sex, age, and BMI at index surgical intervention. Statistical analysis was used to compare categorical and continuous data, cancer incidence, and overall survival between groups. Results: The study included 2,121 bariatric surgical patients. A chronologically concurrent group of 5,528 were identified for eligibility in the control group. After matching, 1,651 bariatric patients were included (1,267 LRYGB and 384 LSG) and 2,181 matched non-surgical patients. The bariatric population's mean preoperative age and BMI were 46.1 +- 10.8 years and 46.1 +- 6.1 kg/m2 (p=0.002). The matched non-surgical population had a mean age and BMI of 47.2 +- 10.8 years and 45.4 +- 6.2 kg/m2 (p=0.0001). The risk of a new cancer diagnosis was significantly lower in the bariatric group compared to the matched controls (HR, 2.67; 95% CI, 2.02-3.51; p = <0.0001). The 10-year incidence (95% CI) of any new cancer in the bariatric group was 5.3% (3.9% - 7.0%), compared to 13.4% (11.5% - 15.3%) in the matched control group (p<0.0001). Conclusion: Obese patients not undergoing bariatric surgery are more likely to develop a new incident cancer.

Methods

This study is a retrospective cohort study that compared (1) bariatric surgical patients, September 2001 - December 2019, and (2) the control population. The control population included non-surgical obese patients (BMI >30 kg/m2) matched by sex, age, and BMI at index surgical intervention. Statistical analysis was used to compare categorical and continuous data, cancer incidence, and overall survival between groups. Results: The study included 2,121 bariatric surgical patients. A chronologically concurrent group of 5,528 were identified for eligibility in the control group. After matching, 1,651 bariatric patients were included (1,267 LRYGB and 384 LSG) and 2,181 matched non-surgical patients. The bariatric population's mean preoperative age and BMI were 46.1 +- 10.8 years and 46.1 +- 6.1 kg/m2 (p=0.002). The matched non-surgical population had a mean age and BMI of 47.2 +- 10.8 years and 45.4 +- 6.2 kg/m2 (p=0.0001). The risk of a new cancer diagnosis was significantly lower in the bariatric group compared to the matched controls (HR, 2.67; 95% CI, 2.02-3.51; p = <0.0001). The 10-year incidence (95% CI) of any new cancer in the bariatric group was 5.3% (3.9% - 7.0%), compared to 13.4% (11.5% - 15.3%) in the matched control group (p<0.0001). Conclusion: Obese patients not undergoing bariatric surgery are more likely to develop a new incident cancer.

Results

The study included 2,121 bariatric surgical patients. A chronologically concurrent group of 5,528 were identified for eligibility in the control group. After matching, 1,651 bariatric patients were included (1,267 LRYGB and 384 LSG) and 2,181 matched non-surgical patients. The bariatric population's mean preoperative age and BMI were 46.1 +- 10.8 years and 46.1 +- 6.1 kg/m2 (p=0.002). The matched non-surgical population had a mean age and BMI of 47.2 +- 10.8 years and 45.4 +- 6.2 kg/m2 (p=0.0001). The risk of a new cancer diagnosis was significantly lower in the bariatric group compared to the matched controls (HR, 2.67; 95% CI, 2.02-3.51; p = <0.0001). The 10-year incidence (95% CI) of any new cancer in the bariatric group was 5.3% (3.9% - 7.0%), compared to 13.4% (11.5% - 15.3%) in the matched control group (p<0.0001). Conclusion: Obese patients not undergoing bariatric surgery are more likely to develop a new incident cancer.

Conclusions

Obese patients not undergoing bariatric surgery are more likely to develop a new incident cancer.