Background/aim: Malnutrition and muscle wasting are common in terminal cancer patients and adversely affect prognosis. Bedside muscle ultrasonography (US) has emerged as a practical tool to assess nutritional status and monitor therapy. This study evaluated the relationship between achieving individualized nutritional targets and changes in muscle indices measured by US in terminal cancer patients receiving palliative care. Materials and methods: Subcutaneous fat tissue thickness (SFTT), muscle thickness (MT), and cross-sectional area (CSA) of the rectus femoris (RF) and biceps brachii (BB) muscles were assessed by US over 10 days and normalized to height squared (m²). A total of 95 patients with complete retrospective data were included; 74.7% achieved their caloric targets, while 25.3% did not. Results: Patients who failed to meet caloric goals exhibited significantly greater reductions across all muscle parameters. Among those who achieved caloric targets, protein intake ≥1.5 g/kg/day was associated with reduced muscle loss compared to lower intake. The RF muscle was particularly sensitive to nutritional status, exhibiting more pronounced changes in response to both caloric and protein adequacy. No significant differences were observed between feeding routes, although patients receiving parenteral nutrition tended to exhibit greater decline. Correlation analyses demonstrated a significant negative association between time to achieve caloric targets and muscle preservation, underscoring the importance of early intervention. Linear regression further identified delayed caloric achievement as an independent predictor of accelerated muscle loss. Conclusion: Achieving caloric and high-protein targets is critical for preserving muscle mass in terminal cancer patients. US, particularly of the RF muscle, provides a reliable, noninvasive, and practical tool for monitoring the effects of nutritional interventions in this vulnerable population.

Background/Objectives: Vitamin D deficiency is linked to muscle loss and fat changes in older adults, but data regarding palliative patients are limited. Ultrasound offers a practical tool to assess these changes. This study explores the relationship between vitamin D levels and ultrasound-measured muscle, fat, and their ratio in older adult palliative patients. Methods: This prospective cross-sectional study was conducted in a tertiary palliative care unit (June–September 2024). A total of 187 patients were grouped by serum vitamin D levels (<50 vs. ≥50 nmol/L). Demographic and clinical variables included sex, BMI, Activities of Daily Living (ADLs), calf circumference (CC), and comorbidities. Ultrasonography assessed muscle thickness (MT), subcutaneous fat thickness (SFT), and cross-sectional area (CSA) of Rectus Femoris (RF) and Biceps Brachii (BB). MT/SFT ratio was calculated. Logistic regression identified independent predictors. Results: Mean age was 75.1 ± 14.4 years; 55.6% of participants were female. Vitamin D deficiency (67.9%) was significantly associated with female sex (p = 0.037), ADL dependency (p < 0.001), lower BMI (p = 0.020), and reduced CC (p = 0.006). RF-MT, RF-SFT, RF-CSA, BB-MT, and BB-CSA were lower in the deficient group. RF-MT/SFT ratio was higher (p = 0.049). ADL dependency (p = 0.002) and RF-MT/SFT (p = 0.015) were independent predictors. Conclusions: Vitamin D deficiency was linked to a higher muscle-to-fat ratio, mainly due to fat loss rather than muscle gain. This may misrepresent muscle preservation and should be interpreted cautiously. Although vitamin D levels appear to be associated with physical function, additional prospective cohort and interventional supplementation studies are warranted to determine whether routine screening and targeted vitamin D supplementation can effectively support physical function in this population.