Effect of obesity on post-operative outcomes following colorectal cancer surgery

BACKGROUND: Colorectal cancer (CRC) resection is currently being undertaken in an increasing number of obese patients. Existing studies have yet to reach a consensus as to whether obesity affects post-operative outcomes following CRC surgery. AIM: To evaluate the post-operative outcomes of obese patients following CRC resection, as well as to determine the post-operative outcomes of obese patients in the subgroup undergoing laparoscopic surgery. METHODS: Six-hundred and fifteen CRC patients who underwent surgery at the Prince Charles Hospital between January 2010 and December 2020 were categorized into two groups based on body mass index (BMI): Obese [BMI ≥ 30, n = 182 (29.6%)] and non-obese [BMI < 30, n = 433 (70.4%)]. Demographics, comorbidities, surgical features, and post-operative outcomes were compared between both groups. Post-operative outcomes were also compared between both groups in the subgroup of patients undergoing laparoscopic surgery [n = 472: BMI ≥ 30, n = 136 (28.8%); BMI < 30, n = 336 (71.2%)]. RESULTS: Obese patients had a higher burden of cardiac (73.1% vs 56.8%; P < 0.001) and respiratory comorbidities (37.4% vs 26.8%; P = 0.01). Obese patients were also more likely to undergo conversion to an open procedure (12.8% vs 5.1%; P = 0.002), but did not experience more post-operative complications (51.6% vs 44.1%; P = 0.06) or high-grade complications (19.2% vs 14.1%; P = 0.11). In the laparoscopic subgroup, however, obesity was associated with a higher prevalence of post-operative complications (47.8% vs 39.3%; P = 0.05) but not high-grade complications (17.6% vs 11.0%; P = 0.07). CONCLUSION: Surgical resection of CRC in obese individuals is safe. A higher prevalence of post-operative complications in obese patients appears to only be in the context of laparoscopic surgery.