Primary Cancer Sites Based on Neck Node Location

The primary cancer sites based on neck node location are as follows:

Level 1. submandibular/submental: lips, buccal mucosa, anterior nasal cavity, soft tissues of the cheek, oral cavity

Level 2. upper jugular: oral cavity, oropharynx, nasopharynx, supraglottic larynx, hypopharynx

Level 3. mid jugular: larynx, hypopharynx, thyroid

Level 4. lower jugular: larynx, thyroid, esophagus, lung, upper GI tract

Level 5. posterior triangle of neck: nasopharynx, thyroid, cervical esophagus

When assessing cervical adenopathy, one should also note the size of the lymph nodes, mobility or possible fixation of these lymph nodes to the skull base, prevertebral muscles, or carotid artery. The neck is staged according to the American Joint Committee on Cancer Clinical Nodal Staging Guidelines (1988).

The skin of the head and neck including the scalp should be assessed, as squamous cell carcinoma or melanoma may metastasize to cervical lymph nodes. The major salivary glands should also be examined. A cranial nerve examination is undertaken.

The oral cavity and the oropharynx are next examined. The patient is requested to remove dentures if these are present. Particular attention is paid to the posterior floor of the mouth and the adjacent tongue and tonsillar fossae as tumors in these areas can be easily missed on a cursory examination. Palpation of the oral cavity and oropharynx should be included in the assessment as some tumors are often palpable before being readily visualized. The ears are evaluated for the possible presence of a middle ear effusion which may be an early finding in cancer of the nasopharynx.

Flexible fiberoptic evaluation of the nasal cavities, the nasopharynx, larynx, and hypopharynx is the next step in the patient's evaluation. Indirect laryngoscopy and nasopharyn-goscopy remain a valuable technique for examination but many physicians simply find the fiberoptic instruments permit a more thorough and detailed evaluation in most patients. The nasal mucosa is prepared by spraying with a topical anesthetic/ vasoconstrictor mix. The nasal mucosa is then carefully evaluated, followed by evaluation of the nasopharynx.

The fiberoptic instrument is now advanced and the hypopharynx and larynx examined. The mobility of the vocal cords should be assessed and during phonation, the depths of the pyriform sinuses and the postcricoid regions may be visualized. The subglottis may be seen during this part of the examination. The tongue base and vallecula should be evaluated and again during phonation, the deeper region of the vallecula including the lingual surface of the epiglottis are usually well seen. The majority of the mucosal surfaces of the larynx, the hypopharynx, and tongue base can thus be thoroughly evaluated. Note should be made of areas of mucosal leukoplakia, ery-throplasia, asymmetry, or friability with easy bleeding, as these areas may harbor neoplastic change. Pooling of secretions in the pyriform sinus may also be a clue to the presence of a tumor in the hypopharynx.

In many patients, the primary carcinoma will be identified following such a thorough examination in an office setting. However, if a primary lesion remains undetected at this point, the patient should undergo a further orderly evaluation to include fine needle aspiration of the neck mass, imaging studies, and endoscopy under anesthesia. An open biopsy of the neck mass is best avoided until the rest of the evaluation has been completed.

A recommendation for delaying an open biopsy of the neck mass has been axiomatic in head and neck surgery for many years. McGuirt and McCabe10 demonstrated an increased incidence of wound necrosis, regional recurrence, and distant metastatic disease in patients who had a nodal biopsy before a full diagnosis and definitive treatment with neck dissection. Other investigators have shared this concern.3'11 However, a subsequent study by Robbins and others, did not corroborate these findings.12-18 Robbins et al.12 concluded that an open biopsy does not signify a poor prognosis provided adequate therapy is subsequently given. Mack et al.13 concluded, based on their data and on a review of the pertinent literature, that excisional biopsy of a solitary neck node does not have a detrimental effect on neck control or distant metastatic rate as long as the next step in treatment includes radiation therapy. Ellis et al.14 concluded that the potential adverse effect of violating the neck before definitive treatment cannot be demonstrated if radiation therapy is the next step in the patient's management. McGuirt's results might be explained by the fact that open biopsy may spread cancer cells into tissues not removed by classic radical neck dissection, but these cells are often sterilized by adequate doses of radiotherapy. However, as many of these patients with neck masses will be diagnosed as having squamous cell carcinoma, an ongoing search for the primary should be undertaken before open biopsy, so that both the primary and neck can receive definitive treatment. It is recommended that an open biopsy take place at the conclusion of the full evaluation.

A fine-needle aspiration biopsy (FNAB) of the neck mass may now be undertaken. A 22-gauge needle and 10 cc syringe are used to obtain the aspirate. Several passes with the needle through different portions of the neck node should be accomplished in order to obtain an adequate sample. If an adequate sample is obtained, and if squamous cell carcinoma is present in the lymph node, there is an approximately 95 to 98% chance of establishing this diagnosis correctly.7 If such a diagnosis is estab lished, the search for the primary tumor should proceed with imaging studies, and endoscopy of the upper aerodigestive tract under anesthesia. The fine-needle aspirate may establish the presence of other malignancies, such as thyroid carcinoma, lymphoma, or adenocarcinoma, in which case the search may be directed to the appropriate regions. Fine-needle aspiration may often establish the histologic diagnosis at this stage. There is no evidence that fine-needle aspiration causes tumor seeding of the needle tract, an increased rate of metastases, or other adverse effects.

If the fine-needle aspirate demonstrates squamous cell carcinoma, the nasopharynx is one possible site of the primary tumor. There is a strong association between carcinoma of the nasopharynx and the Epstein-Barr virus (EBV). High titers of the EBV may be detected in patients with nasopharyngeal carcinoma on serologic testing. The presence of EBV genomes may be detected in cells from the neck aspirate using the polymerase chain reaction (PCR).19 These findings may point to the nasopharynx as the possible site of the primary.

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