Impact of body mass index on tumor recurrence among patients undergoing curative-intent resection of intrahepatic cholangiocarcinoma- a multi-institutional international analysis

Background: The association between body mass index (BMI) and long-term outcomes of patients with ICC has not been well defined. We sought to define the presentation and oncologic outcomes of patients with ICC undergoing curative-intent resection, according to their BMI category. Methods: Patients who underwent resection of ICC were identified in a multi-institutional database. Patients were categorized as normal weight (BMI 18.5–24.9 kg/m²), overweight (BMI 25.0–29.9 kg/m²) and obese (BMI≥30 kg/m²) according to the World Health Organization (WHO) definition. Impact of clinico-pathological factors on recurrence-free survival (RFS) was assessed using Cox proportional hazards model among patients in the three BMI categories. Results: Among a total of 790 patients undergoing curative-intent resection of ICC in the analytic cohort, 399 (50.5%) had normal weight, 274 (34.7%) were overweight and 117 (14.8%) were obese. Caucasian patients were more likely to be obese (66.7%, n = 78) and overweight (47.1%, n = 129) compared with Asian (obese: 18.8%, n = 22; overweight: 46%, n = 126) and other races (obese: 14.5%, n = 17; overweight: 6.9%, n = 19)(p < 0.001). There were no differences in the presence of cirrhosis (10.9%, vs. 12.8%, vs. 12.9%), preoperative jaundice (8.6% vs. 9.5% vs. 12.0%), or levels of CA 19–9 (75, IQR 24.6–280 vs. 50.9, IQR 17.9–232 vs. 43, IQR 16.9–192.7) among the BMI groups (all p > 0.05). On multivariable analysis, increased BMI was an independent risk factor for tumor recurrence (OR 1.16, 95% CI 1.02–1.32, for every 5 unit increase). Conclusion: Increasing BMI was associated with incremental increases in the risk of recurrence following curative-intent resection of ICC. Future studies should aim to achieve a better understanding of BMI-related factors relative to prognosis of patients with ICC.