Abstract LB388: Early postoperative liver outcomes differ by bariatric surgery procedure in multi-site cohort study

Abstract Background: Obesity and metabolic dysfunction are established risk factors for liver cancer and other malignancies. They may enhance the progression of liver disease to advanced stages such as liver cirrhosis and liver failure. Bariatric surgery greatly reduces body weight, but data on the association between bariatric surgery and liver cancer and other advanced stage diseases are sparse. Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG) are two major types of bariatric surgery that have different impacts on weight loss. We evaluated if there was any difference between the two bariatric surgical procedures in risk of developing liver cancer and other advanced stage diseases. Methods: In a cohort study of adults with obesity who underwent RYGB or SG between 2009-2022 from 8 U.S. hospital sites, patients were followed from surgery to first liver-related event, death, or last contact with the healthcare system. The primary outcome was time to first liver-related event defined as liver cancer, decompensated cirrhosis, liver transplant, or liver failure as a composite outcome. Risk associations for individual liver endpoints were also explored. Cox models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) with adjustment for age, sex, comorbidity score, BMI, race, smoking, dyslipidemia, hypertension, type 2 diabetes, and medications for obesity and diabetes at baseline. The overall Cox model did not hold for assumptions. We conducted two separate analyses before and after the cutoff point of 3 years. Results: The cohort included 29,573 patients (14,256 RYGB; 15,317 SG) with average follow-up of 7.7 years and total 59,121 person-years for RYGB and 49,211 for SG. At baseline, the mean (SD) age and BMI were 43.4 (11.5) years and 46.7 (7.4) for RYGB, respectively. The corresponding figures for SG were 42.1 (11.8) years and 46.2 (7.7). The composite outcome was identified for 30 individuals in RYGB and 14 in SG. The incidence rates (per 100,000 person-years) of the composite liver outcomes were 51 in RYGB and 29 in SG. Overall, the difference between the two rates was statistically not significant. In analysis by time interval after bariatric surgery (<3 and 3+ years), patients with RYGB had an adjusted HR of 16.1 (95% CI 5.33-48.9) of composite liver outcomes compared with those with SG during <3 years. There was no significant association during 3+ years. Conclusions: In this large real-world cohort, RYGB was associated with a higher risk of liver-related outcomes compared to SG during the first 3-years after surgery. The early divergence in liver outcomes may reflect different short-term metabolic or inflammatory effects of bariatric procedures, which are biologically relevant to liver disease progression and hepatocarcinogenesis. This emphasizes the clinical relevance of early post-operative monitoring. Our findings support the need for additional long-term analysis of outcomes. Citation Format: Sindhu Karnam, Jaideep Behari, Kathryn Demanelis, Renwei Wang, Jian-Min Yuan. Early postoperative liver outcomes differ by bariatric surgery procedure in multi-site cohort study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(8_Suppl):Abstract nr LB388.