Risk Factors for Poor Survival Outcomes in Parotid Metastatic Cutaneous Squamous Cell Carcinoma

Objective We aimed to analyze risk factors associated with poor survival outcomes for metastatic cutaneous head-and-neck SCC to the parotid. Methods All patients undergoing surgery for metastatic cutaneous SCC to the parotid with curative intent between 2011 and 2018, were reviewed. Demographic and clinical characteristics were evaluated. Histopathological data including tumor size and histology, tumor grade, TNM stage, resection margins, lymphovascular invasion, and perineural invasion, were analyzed. Overall survival (OS), disease-specific survival (DSS), and freedom from locoregional recurrence (LRR) were assessed. Results Ninety patients were included (mean age, 77 years; 75 men [83.3%]). A total parotidectomy was performed in 48 patients (53.3%), and 42 (46.7%) underwent a superficial parotidectomy. Seventy patients (77.8%) underwent adjuvant RT. The median follow-up was 31 months (20-39 months). Tumor volume >= 50 cm(3) and a shorter RT duration (<20 days) were associated with reduced OS (p = 0.002 and p = 0.01, p = 0.02 and p = 0.009, respectively), and DSS (p = 0.004 and p = 0.02, p = 0.04 and p = 0.02, respectively) on univariable and multivariable analysis, respectively. Only a shorter RT duration was associated with worse freedom from LRR on univariable and multivariable analysis, (p = 0.04 and p < 0.001, respectively). However, with death as a competing risk, a shorter duration of RT was not significantly associated with freedom from LRR. Conclusion A shorter duration of adjuvant RT, and excised tumor volume >= 50 cm(3) were predictive factors of reduced OS and DSS, and a shorter duration of RT was also associated with reduced freedom from LRR in patients with metastatic SCC to the parotid gland. Level of Evidence Level 4 Laryngoscope, 2022