Surgery and Adjunctive Therapy

Surgery remains the cornerstone of management for primary parotid malignancies. The extent of resection is TNM grounded. For stage I tumors, <4 cm, low grade, and located in the superficial lobe, a superficial parotidectomy is the procedure of choice. The deep lobe is also removed if it is the primary site, if involved via tumor extension or if microscopic intra-parotid nodes are detected intraoperatively. In rare occasions, otherwise histologically low-grade malignancies (e.g., mucoepi-dermoid carcinoma) are associated with microscopic intraglan-dular nodal extension. These tumors are biologically and clinically more significant. Intraglandular nodal spread because of lymphatic patterns mandates a total parotidectomy. If more than one node is identified, even in the face of low-grade pathology, a supraomohyoid selective neck dissection would be performed. If the neck were positive in the presence of a low histologic grade, radiotherapy would be suggested. If negative, even with intraparotid spread for a low-grade malignancy, radiotherapy would not be considered. Again, as a routine, unless identified preoperatively or suggested above, the neck nodes are not addressed surgically for low-grade stage I parotid malignancies. High grade T1 lesions are managed with total parotidectomy. The facial nerve is preserved unless clinically involved. A neck dissection is not performed unless positive nodes are detected preoperatively (e.g., palpation, imaging, ultrasound-guided aspiration) or intraoperatively with selective nodal sampling of suspicious intraparotid and level I nodes.

For stage II or greater without nodal involvement, the resection is tailored to provide a reasonable margin encompassing areas of local extension. Bone and/or muscle are to be included as indicated. All functioning branches of the facial nerve are preserved whenever possible. If more than one branch is found to supply a given anatomic area, only then is a functional tumor encased branch removed. Neck dissection is performed if positive nodes are encountered at surgery or if the preoperative evaluation infers such. Juxtaposed nodal sampling is routine. Postoperative radiotherapy is essential. If positive nodes are encountered with any T stage, obviously some form of neck dissection is indicated. Nodal size and or number will determine the magnitude of the neck dissection performed. As a general rule, two levels below the lowest identified node are cleared. Nodal status has no direct bearing on the management of the facial nerve.

Any neck nodal involvement in conjunction with a highgrade primary tumor should raise consideration of postoperative chemotherapy. When applicable, this should only be given as part of a planned protocol such that efficacy can be determined. The rationale for the latter is grounded in the knowledge that extended surgical resections correlate with substantively increased recurrence rates.

The precepts put forward are the synthesis of more than two decades of experience with parotid neoplasia. Albeit conservative, this approach provides a needed balance between quality of life, cost, and survival.

REFERENCES

Strome—CHAPTER 65

1. Calearo C, Storchi OF, Pastore A, et al. Parotid gland carcinoma: analysis of prognostic factors. Ann Otol Rhinol Laryn-gol 1998;107:969

2. Cross RR, Shapiro MD, Som PM. MRI of the parapharyngeal space. Radiol Clin North Am 1989;27:353

3. McGurk M, Hussain K. Role of fine needle aspiration cytology in the management of the discrete parotid lump. Ann R Coll Surg Engl 1997;79:198

4. Wheelis RF, Yarington CT Jr. Tumors of the salivary glands: comparison of frozen section diagnosis with final pathologic diagnosis. Arch Otolaryngol 1984;110:76

5. Hillel AD, Fee WE Jr. Evaluation of frozen section in parotid gland surgery. Arch Otolaryngol 1983;104:230

6. Witt RL. Facial nerve monitoring in parotid surgery: the standard of care? Otolaryngol Head Neck Surg 1998;119:468

7. Tu G, Hu Y, Jiang P, Qin D. The superiority of combined therapy in parotid cancer. Arch (Otolaryngol 1982;108:710

8. Matsuba HM, Thawley SE, Devineni VR, et al. High grade malignancies of the parotid gland: effective use of planned combined surgery and irradiation. Laryngoscope 1985;95:1059

9. Griffin TW, Pajak TF, Laramore GE, et al. Neutron vs. photon irradiation of inoperable salivary gland tumors: results of an RTOG-MRC cooperative randomized study. Int J Radiat Oncol BiolPhys 1988;15:1085

10. Phillips PP, Olsen KD. Recurrent pleomorphic adenoma of the parotid gland: report of 126 cases and a review of the literature. Ann OtolRhinolLaryngol 1995;104:100

The Parotid Neoplasm

CHAPTER 66

Ehab Y. Hanna and James Y. Suen

Most parotid masses represent benign neoplasms, most commonly pleomorphic adenoma, originating from the superficial lobe of the gland. Surgical excision is usually all that is required to provide both definitive diagnosis and adequate treatment. Despite this relatively simple algorithm, management of other types of parotid neoplasms is challenging because of their relative infrequency, inconsistent classification, and highly variable biologic behavior. These factors present some difficulty when one attempts to compare data from various institutions describing their experience with parotid tumors. However, some general features can be drawn from the literature regarding the incidence, pathology, and patterns of behavior of benign and malignant tumors of the parotid gland. Despite the large volume of literature describing these salient features, substantial controversy remains regarding several aspects of management of parotid tumors. Some of these controversies concern the role of fine-needle biopsy and high-resolution imaging in the diagnosis of parotid masses. Other controversies exist regarding the extent of resection in benign parotid tumors, management of the facial nerve, the role of elective neck dissection, and the indications of adjuvant radiotherapy. This chapter discusses some of these controversial issues.

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