S184: preoperative sarcopenia is associated with worse short-term outcomes following transanal total mesorectal excision (TaTME) for rectal cancer.

INTRODUCTION: Malnutrition and deconditioning impact postoperative morbidity and mortality. Computed tomography (CT) body composition variables are used as markers of nutritional status and sarcopenia. The objective of this study is to evaluate the impact of sarcopenia, using CT variables, on postoperative outcomes following transanal total mesorectal excision (TaTME) for rectal cancer. METHODS: This was an institutional retrospective cohort analysis of consecutive rectal cancer patients who underwent TaTME between April 2014 and May 2020. Psoas muscle index (PMI) was calculated from diagnostic CT scans. Based on previous studies, patients in the lowest PMI tertile by gender were considered sarcopenic. Fisher's exact and Mann-Whitney U test were used to compare categorical and continuous variables, respectively. Readmission rates and postoperative complications were compared between groups. Backward stepwise logistic regression was used to determine the association between sarcopenia and 30-day postoperative complications. RESULTS: 85 patients were analyzed, of which 63% were male, with a median age of 59 (IQR: 51-65), and median BMI of 28 (IQR: 24-32). Of the entire cohort, 34% (n = 29) were sarcopenic (median PMI 5.39 IQR: 4.49-6.71). No significant difference in baseline characteristics between sarcopenic and nonsarcopenic patients were observed. 55% of sarcopenic patients experienced a complication within 30 days compared to 24% of nonsarcopenic patients (p = 0.01). 41% of sarcopenic patients required hospital readmission within 30 days compared to 17% of their nonsarcopenic counterparts (p = 0.014). Sarcopenic patients also experienced significantly higher rates of post-operative small bowel obstruction (10% vs. 0%, p = 0.04). Multivariable analyses identified that sarcopenic patients have a fourfold increase in odds of experiencing a 30-day postoperative complication (OR: 4.44, 95%CI: 1.6-12.4, p < 0.05) after adjusting for gender. CONCLUSION: Preoperative sarcopenia is associated with increased 30-day postoperative complications following TaTME for rectal cancer. Postoperative complications can have serious oncologic implications by delaying adjuvant chemotherapy. Therefore, preoperative recognition of sarcopenia prior to undergoing TaTME for rectal cancer may provide an opportunity for early intervention with prehabilitation programs.