Impact of fat obesity on laparoscopic total mesorectal excision: more reliable indicator than body mass index

The aim of this study was to evaluate the impact of visceral fat obesity (VFO) on early surgical and oncologic outcomes of laparoscopic total mesorectal excision (LTME) for rectal cancer. Between June 2003 and June 2009, a total of 142 patients who had undergone LTME were included. Patients were divided into the obese group (OG) and the non-obese group (NOG) according to BMI and visceral fat area (VFA). Obesity was defined by BMI a parts per thousand yen25 kg/mA(2) or VFA a parts per thousand yen130 cmA(2). There were 37 (26.0%) and 29 (20.4%) obese patients according to BMI and VFA, respectively. The OG, defined by both VFA and BMI, had a significantly longer operative time. The VFO group experienced more frequent conversion to laparotomy (17.2% vs. 5.0%; P = 0.047) and significantly higher blood loss during surgery (205.8 +/- 257.0 mL vs. 102.5 +/- 219.9 mL; P = 0.031), whereas there was no significant difference when defined by BMI. Time to first flatus was significantly longer in the VFO group compared with the NOG (mean 3.5 days vs. 2.7 days; P = 0.046), whereas it was not significantly different when classified by BMI. Regarding oncologic parameters, the VFO group had a significantly higher number of patients from whom less than 12 total lymph nodes were retrieved (65.5% vs. 34.5%; P = 0.002); however, there was no difference between the two groups defined by BMI. VFO is proven to be a more reliable predictive factor than BMI in estimating early surgical outcomes for patients who underwent LTME. VFO is associated with fewer numbers of retrieved lymph nodes.