ASO Visual Abstract: The Impact of Low Skeletal Muscle Mass on Short- and Long-Term Outcomes After Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy

Background Cytoreductive surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC) is a potentially curative treatment for peritoneal metastases from colorectal cancer (CRC) or pseudomyxoma peritonei (PMP). Because of the considerable morbidity of this treatment, optimal patient selection is key. This study aimed to assess the impact of low skeletal muscle mass (SMM) on outcomes after CRS-HIPEC. Methods Patients who underwent CRS-HIPEC between 2014 and 2020 at a tertiary center were included. SMM was measured on computed tomography by means of the L3 muscle index. Postoperative complications and survival outcomes were compared between groups by use of logistic regression and Kaplan-Meier survival analyses. Results Of 284 included patients, 149 had low SMM. Occurrence of severe postoperative complications did not differ between groups (28.9% for patients with low vs. 34.1% for patients with normal SMM). Low SMM was not associated with postoperative complications ( p = 0.344). For CRC patients, no significant differences were observed in disease-free (DFS) or overall survival (OS) between patients with low (median DFS 7 months [IQR 4–14], median OS 33 months [IQR 14–NR]) and patients with normal SMM (median DFS 8 months [IQR 5–20], median OS 35 months [IQR 18–NR]). Regarding PMP, survival outcomes did not significantly differ between groups (3-year DFS 47.3% for patients with low SMM vs. 54.5% for patients with normal SMM, p = 0.676; 3-year OS 70.8% vs. 90.9% respectively, p = 0.172). Conclusions Low SMM could not be identified as a predictor of severe complications or survival outcomes after CRS-HIPEC.