Elective Neck Dissection in Lymphatic Basins

Removal of At-Risk Lymphatic Basins

• Serves two purposes: removing occult metastasis in patients at risk and removing macroscopic disease in patients with highly suspected metastasis
• Elective neck dissection is a more accurate term than prophylactic neck dissection when discussing removal of at-risk lymphatic basins in the absence of clinical evidence of metastasis

Classification of Neck Dissection

• Radical neck dissection:
  • Refers to removal of all ipsilateral cervical lymph node groups from the inferior border of the mandible to the clavicle
  • Includes removal of the internal jugular vein, sternocleidomastoid muscle, and spinal accessory nerve
  • Encompasses levels I-V
• Modified radical neck dissection:
  • Refers to removal of the same lymph node levels as radical neck dissection, but with preservation of the spinal accessory nerve, internal jugular vein, or sternocleidomastoid muscle
  • Structures preserved should be named
  • Can be subdivided into three types: Type I (preserves spinal accessory nerve), Type II (preserves spinal accessory nerve and sternocleidomastoid muscle)
• Selective neck dissection:
  • Refers to preservation of one or more lymph node groups normally removed in a radical neck dissection
  • Example: supraomohyoid neck dissection removes lymph nodes from levels I-III
  • Named for the cancer being treated and node groups removed in parentheses
• Extended neck dissection:
  • Refers to removal of one or more additional lymph node groups, nonlymphatic structures, or both, not encompassed by a radical neck dissection
  • Example: mediastinal nodes or nonlymphatic structures such as the carotid artery or hypoglossal nerve

SCC of the Buccal Mucosa

• Represents approximately 10% of oral cavity cancers in the United States and 41% in India
• Can be deceptive in their clinical course due to intimacy with the buccal space and deeper structures
• Cancers that penetrate the buccinator muscle can be difficult to eradicate
• Patients may present with involvement of the pterygoid space posteriorly or the parotid gland laterally
• Extension superiorly or inferiorly can lead to invasion of the maxillary alveolus or mandibular alveolus, respectively
• Often arise in wide areas of damaged mucosa, making adequate excision resulting in complex defects of the cheek that can be difficult to reconstruct
• Primary radiation may be an option for smaller lesions
• Up to 50% of patients with buccal squamous cell carcinoma can present with neck metastases, with an occult disease rate in the neck of approximately 10%
• Elective treatment of the neck with radiation or surgery is indicated in T3 or T4 lesions, and consideration should be given to elective treatment of the neck in deep T1 (>4 mm) and larger T2 lesions

Neck Dissection and Survival Rates

• Appropriate surgical management of the regional lymphatics plays a central role in the treatment of oral cancer patients
• Two-year overall survival rates for early-stage disease treated with various treatment modalities range from 83% to 100%
• Stage III survival rate is 41%, and stage IV is 15%

Understanding the importance and purposes of removal of at-risk lymphatic basins, including identifying occult metastasis in patients.