Risk of misclassification during diagnosis of malnutrition in retroperitoneal sarcoma patients

Retroperitoneal sarcoma (RPS) is a rare tumour that can reach exceptionally large size at diagnosis and affects body weight with its volume. We investigated the risk of nutritional status misclassification based on the Global Leadership Initiative on Malnutrition (GLIM) criteria in RPS patients.

We retrospectively analyzed the baseline data of patients with primary RPS including anthropometry, Malnutrition Universal Screening Tool (MUST) score and skeletal muscle index (SMI) calculated on preoperative CT scan. Phenotypic GLIM criteria considered were non-volitional weight loss, low-BMI and low muscle mass. MUST score, being inclusive of weight loss, was chosen as its surrogate. Reduced muscle mass was defined with SMI cut-offs <38.5-52.4 cm²/m² for female and male respectively.

From 2018 to 2020, 100 consecutive patients (male/female: 48/52) were included. Median age was 61 (48-68) years, median BMI 24.6 (21.5-27.4) kg/m². Seven patients (7%) reported MUST score ≥2 and 80 (80%) score 0. Five patients (5%) were underweight, 44 (44%) overweight and obese. Sixty patients (60%) presented low SMI, of those 56 (93%) were normal or overweight, and 46 (77%) not at nutritional risk according to the MUST score. Both underweight BMI and MUST score ≥2 were not correlated with low SMI (p = 0.406, p = 0.612, respectively). No relevant discrepancy was found in the postoperative course of patients with low or normal muscle mass, although SMI was able to better characterize nutritional risk in the proportion of patents with high-grade liposarcoma and predicted worst overall survival.

GLIM criteria are a useful tool for diagnosis of malnutrition. However, our analysis suggests that phenotypic criteria are not interchangeable with each other. An altered body composition is often hidden in patients with retroperitoneal sarcoma and the use of weight-based classification does not seem to be appropriate, enhancing the role of mass muscle measurement to prevent misdetections of malnourished patient.