Sarcopenia and postoperative outcomes in patients with peritoneal carcinomatosis undergoing cytoreductive surgery with hyperthermic intraperitoneal chemotherapy.

e15604 Background: Multiple primary neoplasms spread to the peritoneal cavity, previously considered an untreatable and terminal condition. Cytoreductive surgery plus hyperthermic chemotherapy (CRS-HIPEC) improved the prognosis, nonetheless, it is a procedure with associated morbidity. This study aimed to determine the association between sarcopenia and postoperative outcomes in patients with peritoneal carcinomatosis (PC) undergoing CRS-HIPEC. Methods: This retrospective, observational, analytic study included patients with PC who underwent CRS-HIPEC between January 2010 and December 2022. Eligible patients had complete follow-up data and available preoperative images. Sarcopenia was assessed using the L3 skeletal muscle index (SMI) on preoperative abdominal CT, estimating its prevalence and participants were classified as sarcopenic (SC) or non-sarcopenic (NSC) based on Fearon et al.’s cutoff values. Clinical and surgical variables during hospitalization were assessed through univariate and bivariate analysis and survival was analyzed using Kaplan- Meier curves and Cox regression models. Results: 156 patients were included, with a mean age of 52.33 years (± 11.01 SD). The majority were women (n=112, 71.9%), and the most common primary cancer was of appendiceal origin (n=69, 44.52%). Preoperative CT identified sarcopenia in 64.74% (n=101), with a mean body mass index (BMI) of 24.45 (SD ± 3.41). Except for BMI (23.75 kg/m² for SC patients vs. 25.74 kg/m² for the NSC group; p=0.001), no differences were observed between groups. Subgroup analysis by primary cancer type also showed no significant differences. Regarding survival, the NSC group had an average overall survival of 111,7 months, compared to 98,4 months in the SC group (p= 0,479). However, disease-free survival was significantly longer in the NSC group (91,48 months) compared to the SC group (74,07 months) (p= 0,025). Sarcopenia significantly increased the risk of recurrence (p = 0.030), with an 81.8% higher risk; conversely, neoplasm origin did not affect recurrence (p = 0.168). Neoplasm origin was significantly associated with mortality (p= 0.001). Furthermore, pre-surgical PCI correlated with mortality risk (p=0.022). Conclusions: Low SMI was not associated with immediate postoperative complications, suggesting that preoperative nutritional recovery may not be critical, potentially preventing treatment delays by facilitating timely surgical intervention. Sarcopenia was linked to shorter disease-free survival and higher recurrence rates in patients with PC, indicating that postoperative nutritional support may enhance long-term outcomes.