BACKGROUND The impact of obesity on survival is known to vary in different cancers. Advanced biliary tract cancer was rarely analyzed about the relationship between obesity and prognosis. We performed this study to evaluate the BMI and body weight change as prognostic factors for advanced biliary tract cancer patients with palliative chemotherapy.

METHODS Between January 2005 and December 2016, two hundred and seventy-six patients who underwent chemotherapy for biliary tract cancer were retrospectively analyzed. The relationship between BMI (kg/m2) and clinical outcomes including overall and progression-free survival was assessed. Additionally the relationship between change in body composition and overall survival was evaluated.

RESULTS Median overall survival was 9.7 months for underweight patients, 10.1 months for normal patients, 15.8 months for overweight group, 13.1 months for obese patients, respectively. (p = 0.047) Univariate analysis showed that BMI, stage III, age less than 64 year-old, gallbladder cancer, operation, radiotherapy and ECOG performance were significantly associated with better survival. Compared with normal patients, overweight patients (BMI 23-24.9kg/m2) had a reduced risk of mortality in multivariate analysis (HR 0.632; 95% CI 0.436-0.918, p = 0.016). In the additional analysis for the effect of changes in body weight and BMI to the overall survival, decrease in body weight and BMI (HR 1.410, 95% CI 1.168-1.986, p = 0.046) was associated with a shorter in overall survival.

CONCLUSION Overweight status and the maintenance of body weight during the initial period of chemotherapy are important and independent predictors of better overall survival in advanced biliary tract cancer patients.