Systematic review of management and survival outcome of parotid cancers with lateral skull base invasion

Lateral skull base involvement from parotid cancers is a rare condition and is considered a poor prognostic indicator. The aim of this study was to systematically review the literature of parotid tumors with temporal bone invasion to analyze the survival outcome. A systematic literature review was performed in August 2022, without time limits, and 289 patients affected by parotid gland cancers and lateral skull base involvement were included. The most common symptoms in parotid tumors at the onset were indolent mass, facial weakness, pain, and hearing loss; the chi-square value is 23.1063, with a statistically significance (p = < 0.000121). The five most common histologies were adenoid cystic carcinoma, acinic cell carcinoma, mucoepidermoid carcinoma, adenocarcinoma, and squamous cell carcinoma. The facial nerve function after surgery showed statistically significance (functional vs. non-functional; chi-square was 91.7698, p = < 0.00001). Mean follow-up was 36.2 months (range 0.3-192). At the last follow-up, more patients died of disease (DOD; 60/289, 21%) than other causes (DOOC; 5/289, 2%). There is a statistically significant correlation between patients died for tumor (DOD) and patients died for other causes (DOOC) (p = < 0.0001), suggesting that the lateral skull base invasion negatively impacts on survival. Basing on the results of our systematic review, lateral skull base involvement from parotid recurrent/advance tumors should be considered a poor prognostic factor, as the majority of patients die due to this condition. It also would be necessary to have "clear"works, with full data (demographic, clinical, surgical data), and with a longer follow up, in order to assess the best treatment modality of these patients.