Prognostic impact of MRI-based cervical skeletal muscle mass on survival in parotid gland carcinoma.

BACKGROUND

Parotid gland carcinoma (PGC) is rare and prognostic evidence is limited, making preoperative risk stratification challenging. We evaluated the prognostic relevance of pretreatment skeletal muscle mass measured on routine cervical magnetic resonance imaging.

METHODS

We retrospectively analyzed 58 patients with histopathologically confirmed PGC treated between 1991 and 2024. Cervical skeletal muscle mass was quantified as the C3 skeletal muscle index (C3SMI) using axial T2-weighted magnetic resonance imaging (MRI) at the C3 level. Overall survival (OS) and recurrence-free survival (RFS) were assessed using Kaplan-Meier analysis and Cox proportional hazards models.

RESULTS

Low C3SMI was significantly associated with worse OS and RFS on Kaplan-Meier analysis. In multivariable Cox models restricted to pretreatment variables, low C3SMI remained an independent predictor of shorter OS and RFS. In addition, low C3SMI was significantly associated with adverse pathological features, including high-grade histology, perineural invasion, extracapsular extension, and lymphovascular invasion.

CONCLUSIONS

MRI-derived C3SMI is an independent prognostic biomarker for survival and recurrence in PGC and correlates with pathological aggressiveness. Because C3SMI can be obtained from standard preoperative cervical MRI without additional imaging or radiation exposure, it may provide a practical tool for preoperative risk stratification and treatment planning in patients with PGC.