Prognosis of T4b parotid gland squamous cell carcinoma: a population-based study

BACKGROUND: The optimal treatment strategy for T4b parotid gland squamous cell carcinoma (PSCC) remains unclear. AIM/OBJECTIVES: To evaluate the survival outcomes of T4b PSCC according to the treatment modality. SUBJECTS AND METHODS: Patients with T4b PSCC without distant metastases were identified from the Surveillance, Epidemiology, and End Results database. Overall survival (OS) and cancer-specific survival (CSS) were analysed using the Kaplan-Meier method and compared using the log-rank test. Multivariate analyses were performed using Cox proportional hazards models. RESULTS: A total of 163 patients were enrolled in the study. The five-year OS and CSS rates were 27.6% and 36.9%, respectively. Surgical treatment and chemoradiotherapy (CRT) demonstrated comparable survival outcomes (five-year OS rates: 38.2% and 30.8%). Multivariate Cox analyses confirmed that CRT was associated with survival outcomes comparable to surgery (hazard ratios 1.19 for OS and 1.03 for CSS). Among surgically treated patients, adjuvant CRT showed a trend towards improved survival. CONCLUSIONS AND SIGNIFICANCE: CRT provides survival outcomes comparable to those of surgery in T4b PSCC. Surgery followed by adjuvant CRT may offer additional benefits to selected patients. These findings support individualised treatment selection and shared decision-making for this rare disease.