P335 - MUSCLE MASS INDEX CHANGES AFFECT SURVIVAL OUTCOMES IN HEAD AND NECK CANCER WITH DISTANT METASTASIS DURING PALLIATIVE CHEMOTHERAPY

P335

MUSCLE MASS INDEX CHANGES AFFECT SURVIVAL OUTCOMES IN HEAD AND NECK CANCER WITH DISTANT METASTASIS DURING PALLIATIVE CHEMOTHERAPY

J. Janprasert^1,*

¹Otolaryngology, Internal medicine, Prince of songkla university hospital, Songkla, Thailand

Rationale: Sarcopenia is a key prognostic factor in metastatic head and neck cancer (HNC), affecting survival and treatment tolerance. While prior studies have linked low skeletal muscle index (SMI) to poor outcomes, most rely on static measurements rather than dynamic changes over time. This study evaluates six-month SMI changes as a predictor of survival and chemotherapy-related toxicity.

Methods: A retrospective cohort study of 322 metastatic HNC patients receiving palliative chemotherapy at Songklanagarind Hospital (2018–2023). SMI was measured via CT at C3 at baseline and six months. Patients were categorized into decreased SMI and stable/increased SMI groups. Kaplan-Meier and Cox regression analyses assessed survival, while logistic regression evaluated chemotherapy-related toxicity.

Results: Patients with decreased SMI had significantly shorter survival than those with stable/increased SMI (adjusted HR: 0.23, 95% CI: 0.14–0.40, p < 0.001). Underweight patients had nearly twice the mortality risk (HR: 1.88, p = 0.001). Greater percentage weight loss correlated with worse survival (HR: 1.64, p = 0.039). Patients aged ≥65 years showed better survival (adjusted HR: 0.69, p = 0.045), while multiple metastatic sites were associated with worse outcomes (adjusted HR: 0.63, p = 0.011).

Conclusion: Dynamic SMI changes over six months predict survival and chemotherapy tolerance in metastatic HNC. Routine SMI monitoring should be integrated into oncologic care to enable early interventions, including nutritional support and muscle preservation strategies, to improve patient outcomes.

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Disclosure of Interest: None declared