Optimizing Nutritional Support in Advanced Non-Small Cell Lung Cancer: Evidence and Controversies in Oral, Enteral, and Parenteral Approaches.

Malnutrition and cachexia affect the majority of patients with advanced lung cancer, driven by systemic inflammation (IL-6, TNF-α), metabolic dysregulation, and anorexia. These conditions worsen prognosis, reduce treatment tolerance, and diminish quality of life (QoL) and survival. Early recognition, utilizing tools such as the Patient-Generated Subjective Global Assessment (PG-SGA), is crucial. Nutritional support should align with patient-centered goals, prioritizing function and QoL rather than survival alone. Oral nutritional supplements (ONS), especially high-protein/EPA (eicosapentaenoic acid)- enriched formulas, enhance weight, muscle mass, and QoL but often face adherence challenges. Enteral nutrition (EN) supports patients with functional GI tracts and impaired intake (e.g., dysphagia), improving biomarkers and reducing complications. Parenteral nutrition (PN) should be limited to patients with intestinal failure due to infection risks and minimal survival benefits. Multimodal care, encompassing nutrition, exercise, and pharmacotherapy (e.g., appetite stimulants, investigational agents such as anamorelin), is crucial. Ethical, cultural, and legal considerations must guide decisions around artificial nutrition, emphasizing autonomy, informed consent, and respect for cultural beliefs. Barriers such as inconsistent screening and limited resources persist. Future research should focus on lung cancer-specific trials of EN, standardized cachexia definitions, and equitable access to nutritional support, especially in underserved populations.