Increased local recurrence in advanced parotid malignancy treated with mastoidectomy without lateral temporal bone resection

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.

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

OBJECTIVE(S)

Although parotid cancer invading into the temporal bone makes up only a small fraction of all parotid cancers, it is more common and relatively understudied compared with primary cancer of the external auditory canal. The objective of this study was to determine what factors are associated with receiving parotidectomy with temporal bone resection (TBR) and the immediate postoperative outcomes.

METHODS

We reviewed the National Cancer Database (2004-2015) for patients with primary parotid malignancy who received parotidectomy with or without TBR. Patient demographic, clinical, and perioperative variables were collected and then compared. Multivariate logistic regression was performed to determine factors associated with receiving TBR.

RESULTS

We identified 134 patients who received parotidectomy with TBR and 16,595 who received parotidectomy only. Reported in terms of odds ratios (95% confidence interval), our multivariate model showed having surgery at an academic facility (1.91 [1.34-2.71], P < .001), clinical stage III or IV (7.48 [1.65-33.96] and 31.37 [7.61-129.32], P = .009 and P < .001, respectively), histologic grade II to IV (4.36 [1.51-12.57], 4.31 [1.53-12.15], and 6.74 [2.26-20.13], P = .006, .006, and .001, respectively), and adenoid cystic histology (3.23 [2.02-5.17], P < .001) were significantly and independently associated with receiving TBR. There was no significant difference in 30-day readmission, or 30-day or 90-day mortality, but the rate of positive surgical margins was significantly higher in those who underwent TBR.

CONCLUSION

Demographic variables are not significant factors for receiving TBR. Tumor characteristics, such as clinical stage and histologic type, and receiving surgical treatment at an academic facility were more strongly associated with receiving TBR.

LEVEL OF EVIDENCE

3 Laryngoscope, 131:E2461-E2468, 2021.