Outcomes according to body mass index following laparoscopic surgery in patients with colorectal cancer

PURPOSE: Body mass index (BMI) may not be appropriate for different populations. Therefore, the World Health Organization (WHO) suggested 25 kg/m(2) as a measure of obesity for Asian populations. The purpose of this report was to compare the oncologic outcomes of laparoscopic colorectal resection with BMI classified from the WHO Asia-Pacific perspective. PATIENTS AND METHODS: All patients underwent laparoscopic colorectal resection from September 2006 to March 2015 at a tertiary referral hospital. A total of 2408 patients were included and classified into four groups: underweight (n = 112, BMI <18.5 kg/m(2)), normal (n = 886, 18.5–22.9 kg/m(2)), pre-obese (n = 655, 23–24.9 kg/m(2)) and obese (n = 755, >25 kg/m(2)). Perioperative parameters and oncologic outcomes were analysed amongst groups. RESULTS: Conversion rate was the highest in the underweight group (2.7%, P < 0.001), whereas the obese group had the fewest harvested lymph nodes (21.7, P < 0.001). Comparing oncologic outcomes except Stage IV, the underweight group was lowest for overall (P = 0.007) and cancer-specific survival (P = 0.002). The underweight group had the lowest proportion of national health insurance but the highest rate of medical care (P = 0.012). CONCLUSION: The obese group had the fewest harvested lymph nodes, whereas the underweight group had the highest estimated blood loss, conversion rate to open approaches and the poorest overall and cancer-specific survivals.