Impact of Nutritional and Radiomic Index of Sarcopenia in Retroperitoneal Sarcoma

Background: Sarcopenia, characterised by loss of skeletal muscle mass, strength and function, negatively impacts surgical outcomes in oncology, including complications, prolonged hospitalisations and reduced survival. This study investigated the relationship between nutritional and radiomic indices and tumour burden in sarcopenic versus non-sarcopenic patients with retroperitoneal soft tissue sarcoma (STS).

Method: A retrospective analysis was conducted on patients with retroperitoneal STS treated at the Midlands Abdominal Retroperitoneal Sarcoma Unit (MARSU) between June 2023 and December 2024. Nutritional status and sarcopenia were evaluated using body mass index (BMI), prognostic nutritional index (PNI), skeletal muscle index (SMI) and total psoas index (TPI). Correlations were explored between sarcopenia, tumour burden (volume and weight) and clinical outcomes including survival.

Results: The study included 73 patients: 57 with liposarcoma (LPS) and 16 with leiomyosarcoma (LMS). Most had an ECOG performance status of 0. Sarcopenia was present in 57.9% of LPS and 37.5% of LMS patients preoperatively. Among LPS patients, sarcopenia was significantly associated with a lower PNI (p = 0.05), suggesting poorer nutritional status. Sarcopenia showed no significant correlation with tumour volume or weight in either cohort. Similarly, it did not significantly affect hospital stay length in LPS (p = 0.475) or LMS (p = 0.328). Median follow-up was 14.6 months (range: 6.5–37.8). Recurrence was more common in sarcopenic patients; however, disease-free survival (DFS) in sarcopenic LPS cases did not reach statistical significance (p = 0.117). Survival analysis in LMS was limited due to censored data.

Conclusions: PNI serves as a reliable marker for identifying sarcopenic patients and may guide preoperative nutritional and physical rehabilitation strategies to enhance surgical outcomes. Although early recurrence trends were observed, larger cohorts and extended follow-up are necessary to validate associations with overall survival (OS) and further define prognostic implications.