Influence of body mass index on complications and oncologic outcomes following hepatectomy for malignancy

Background: Following hepatectomy for malignancy, the effect of body mass index (BMI) on hepatic and oncologic outcomes is unknown. Methods: Two hundred seventy-nine post-hepatectomy patients with malignancy from our center were included in the cohort (1996-2006). BMI was categorized using World Health Organization criteria. The effect of BMI was evaluated using risk-adjusted Cox models for time to recurrence and overall survival. Results: Seventy-nine patients (28.3%) had primary hepatobiliary cancers, 134 (48.0%) had colorectal metastases, and 66 (25.3%) had other metastases. Thirty-five percent of patients were obese (BMI > 30). Obese patients had more hepatic-specific perioperative complications (27.8% vs. 15.9%, p = 0.018), bile leaks (18.6% vs. 9.9%, p = 0.030), post-operative pneumonia (9.3% vs. 2.2%, p = 0.0074), intra-abdominal abscesses (7.2% vs. 1.7%, p = 0.017), acute renal failure (7.2% vs. 1.7%, p = 0. 017), urinary tract infections (16.4% vs. 7.7%, p = 0.024), and longer lengths of stay (10.5 vs. 8.6 days, p = 0.029). Obese and non-obese patients had similar perioperative mortality, time to recurrence, and overall survival on univariate analysis. However, after adjusting for demographic, tumor, and operative characteristics, and complications, increasing BMI displayed improved recurrence-free (HR 0.90, 95% CI 0.86-0.95) and overall survival (HR 0.96, 95% CI 0.92-0.99). Conclusions: High BMI patients may have better oncologic outcomes despite higher perioperative morbidity and hepatic complications following hepatectomy. These findings have important clinical and biological implications.