Factors and Outcomes Associated With Temporal Bone Resection for Primary Parotid Malignancy

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.

The contribution of oncological lateral skull base surgery to the management of advanced head-neck tumors

BACKGROUND

Lateral skull base is a complex area between the brain and the neck that is characterized by a large anatomic variability in narrow spaces and wide heterogeneity of tissues. The complexity of the anatomy makes it more difficult to accurately identify tumor spread and surgical planning is here particularly demanding.

AIMS

Oncological skull base surgery is conceived for malignant lesions originating in, secondarily infiltrating, or in close proximity to the lateral skull base. It is also conceived for selected aggressive or benign lesions of the parapharyngeal space and infratemporal fossa abutting the skull base, or crossing it from above downwards to the neck. This paper is focused on the role that oncological skull base surgery plays to resect tumors in this area.

METHODS AND RESULTS

Three main types of head and neck lesions can be identified as paradigms of the philosophy of oncological lateral skull base surgery, and are herein presented: (i) primary malignant tumors of the ear; (ii) advanced malignant parotid tumors; (iii) primary malignant or locally aggressive tumors of the infratemporal fossa-parapharyngeal space. The en-bloc lateral and subtotal temporal bone resections, the en-bloc temporo-parotid resection and the combined subtemporal-transcervical-transparotid resection are described, respectively.

CONCLUSIONS AND SIGNIFICANCE

Different histologies are found in the lateral skull base and adjacent areas, and each histology has its own pattern of growth and undetected spreading in a difficult-to-reach surgical area. The leading principle is to create a wide access through soft tissues and bone removal far enough from the tumor to obtain a complete resection, en-bloc radical resection in malignancies. The entity of dissection is obviously modulated on the tumor triad (histology, pattern of growth, extent) and is achieved through the en-bloc and combined approaches that are here described.