The impact of visceral obesity on the outcomes after resection of colorectal cancer: a systematic review and meta-analysis.

Obesity is closely associated with the initiation and progression of colorectal cancer (CRC) and is widely recognized as a risk factor for unfavorable surgical outcomes. Nevertheless, the extent to which visceral obesity specifically influences perioperative safety and long-term oncologic outcomes following CRC resection remains to be established. We performed a systematic review and meta-analysis by comprehensively searching PubMed, Web of Science, Embase, Scopus, and the Cochrane Library. Continuous, dichotomous, and survival-related variables were synthesized using weighted mean difference (MD) or standardized MD (SMD), odds ratios (ORs), and hazard ratios (HRs), respectively. A total of 23 studies comprising 6,500 patients were included. Relative to patients without visceral obesity, those with visceral obesity demonstrated significantly prolonged operative time, greater intraoperative blood loss, higher rates of conversion to open laparotomy, increased overall postoperative complication rates, higher incidences of incisional wound infection and anastomotic leakage, a reduced number of harvested lymph nodes, and extended postoperative hospital stay. In contrast, no statistically significant differences were identified in postoperative mortality, positive surgical margin rates, time to first flatus, urinary dysfunction, 5-year disease-free survival, or 5-year overall survival. Collectively, these findings indicate that visceral obesity substantially increases intraoperative technical difficulty and postoperative morbidity; however, it does not appear to compromise long-term oncologic outcomes following CRC resection.