Identifying markers of cachexia and nutritional deficit on radical radiotherapy outcomes in lung and head and neck cancer

PURPOSE OF REVIEW: Cancer cachexia is a multifactorial syndrome characterised by weight loss, muscle wasting, malnutrition, and systemic inflammation. Although well-recognised in advanced cancer, its significance in patients receiving radical radiotherapy for potentially curable malignancies is less well understood. This review examines the impact of cachexia-related biomarkers in patients undergoing radical radiotherapy for lung or head and neck cancers. RECENT FINDINGS: Many studies evaluating cachexia-related phenotypes do not explicitly use the term 'cachexia'. Therefore, this review focuses on four key domains of cachexia: weight loss, malnutrition, sarcopenia, and systemic inflammation. Across both tumour types, these biomarkers were frequently associated with poorer survival, increased treatment toxicity, and reduced treatment tolerance in patients receiving radical radiotherapy with curative intent for lung or head and neck cancers. However, the literature is dominated by retrospective studies employing heterogeneous definitions in poorly defined patient groups. SUMMARY: Cachexia-related biomarkers provide important prognostic information in patients receiving radical radiotherapy for lung cancer and head and neck cancer. Routine assessment of weight loss, nutritional status, body composition, and systemic inflammation may improve risk stratification and support personalised treatment decisions. Future prospective studies should incorporate standardised cachexia assessments to validate their clinical utility and evaluate emerging nutritional, prehabilitation, and anti-cachexia interventions.