ESTRO 2025 - Abstract Book

S1042

Clinical – Head & neck

ESTRO 2025

treatment-related toxicity across various solid tumors. This study focuses on exploring the relationship between sarcopenia, as assessed by MRI, and the survival outcomes of nasopharyngeal cancer (NPC) patients.

Material/Methods: This is a multi-institute study. There were 976 patients with NPC treated at Taipei Medical University Hospital, Shuang-Ho Hospital and Wan-Fang Hospital between 2002-2019. 504 patients were newly diagnosed with NPC and treated with concurrent chemoradiotherapy. Pretreatment MRI of 292 patients were analyzed. Sarcopenia was assessed by measuring the cross-sectional area (CSA) of the sternocleidomastoid (SCM) muscle at the level of the third cervical vertebra. Axial MRI images were utilized to delineate the CSA of the SCM muscle, employing the 3D Slicer software for segmentation. The obtained CSA values were then normalized to the patient’s height squared (m²) to calculate the sternocleidomastoid muscle index (SCMI), expressed in cm²/m². Gender-based cutoff values were applied to determine the presence of sarcopenia. Predictors of overall survival (OS) were evaluated using Cox proportional hazards regression models to estimate hazard ratios and their corresponding confidence intervals. Additionally, Kaplan-Meier (KM) survival analysis was conducted to visualize OS differences between groups stratified by sarcopenia status or other relevant predictors. Results: This cohort consists of 184 male patients, accounting for 63% of the total population. The majority of patients (51.2%) were diagnosed between the ages of 40 and 60. At diagnosis, most patients presented with advanced disease, with 40.7% classified as stage IV and 25.8% as stage III. The median follow-up period was 4.7 years, during which 93 patients died. The crude overall survival rates were 93.2% at one year and 68.9% at five years. The mean sternocleidomastoid muscle index (SCMI) was 0.97 cm²/m² for males and 0.77 for females. The cutoff values for defining sarcopenia were determined to be 0.73 cm²/m² for males and 0.52 for females. KM survival analysis revealed a statistically significant difference in overall survival between groups with and without sarcopenia, with a log-rank test result of p < 0.001. Conclusion: Low BMI alone may not sufficiently reflect the overall physiological condition. In contrast, SCMI measurements derived from pretreatment MRI images provide a reliable approach for assessing sarcopenia. Our findings suggest that SCMI is an effective metric for evaluating sarcopenia and predicting poor overall survival in patients with nasopharyngeal cancer. References: Kamarajah, S. K., Bundred, J. R., Weblin, J., & Alrawashdeh, W. (2018). Impact of preoperative sarcopenia on post operative outcomes following gastrointestinal surgery: A meta-analysis. Journal of Surgical Research, 229 , 23–36. Nakanishi, R., Oki, E., Sasaki, S., Hirota, S., Edahiro, Y., Taketani, K., ... & Maehara, Y. (2022). Sarcopenia as a predictor of poor survival outcomes in patients undergoing chemotherapy for advanced gastric cancer. Journal of Geriatric Oncology, 13 (4), 526–532. Lee, C. S., Kim, Y., Hwang, H., Kim, K. T., & Yoon, H. S. (2021). The prognostic significance of sarcopenia in patients with head and neck squamous cell carcinoma. Oral Oncology, 118 , 105327. Keywords: NPC, Sarcopenia