Head and Neck Cancer - Resection and Neck Dissection Workup

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• Imaging studies can be useful in assessing primary lesions and in evaluating cervical metastases.

• Computed tomography (CT) scans, generally with intravenous contrast administration, are often useful in detecting the extent of tumor infiltration into deep musculature and the involvement of adjacent bone. CT scans are also useful as an indicator of malignancy in a cervical lymph node. Although various authors report a size of 1.2-1.5 cm as suggestive of malignancy, necrosis is a much more reliable indicator.

• Ultrasonography is less sensitive in the detection of cervical lymph node metastases, and magnetic resonance imaging (MRI) is as sensitive as CT in a comparison of the 3 modalities. The least accurate method for detecting cervical metastases is palpation.

• Additional studies, including DentaScans, may help in detecting the extent of bony involvement.

• Positron emission tomography (PET) scanning is being used more frequently in patient workup. Preoperatively, PET scanning is useful to assess not only the primary tumor but also locoregional metastatic disease (metastatic adenopathy) and distant metastatic disease. In the posttreatment stage, PET scanning is increasingly used to determine the response to nonsurgical methods of treatment and to assess for residual disease.

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• Fine-needle aspiration

  • Fine-needle aspiration (FNA) of solitary neck masses has revolutionized the evaluation and treatment of patients with aerodigestive malignancies. It has virtually eliminated the need for open biopsy of metastatic cervical lymphadenopathy and the sequela of violating tissue planes prior to undertaking the definitive treatment of the tumor.

  • FNA is particularly useful in evaluating a patient in whom a primary tumor is not evident at initial presentation and should be the second step in the workup, preceded only by a complete history and physical examination. Consider open biopsy only after other noninvasive workup has not yielded a diagnosis.

  • FNA is also quite helpful in differentiating sources of a tumor. It can help to differentiate metastatic squamous cell adenopathy from metastatic thyroid malignancies and even from enlarged lymph nodes secondary to lymphoproliferative and reactive adenopathy.

  • A fine-needle aspirate that yields lymphocytes is not necessarily nondiagnostic, depending on the context. In addition, an aspirate that demonstrates no evidence of malignancy must be reassessed if the clinical situation is suggestive of malignancy; the burden of proof is on the examiner.

Staging of head and neck cancers has changed throughout the years as new information becomes available about various methods of treatment. Keep this in mind, particularly when reading older reports of stages of cancer and their prognosis, since a cancer that was classified as one stage years ago may now be classified as another stage.

Presently, the extent of the tumor is the primary basis for staging. This incorporates the primary tumor as well as nodal disease and distant metastatic disease. In squamous cell carcinomas of the head and neck, the extent of differentiation and patient age are not considered, yet these factors are considered in thyroid carcinomas.

• The regional lymph node metastases and their effect on stage grouping are fairly consistent throughout all anatomic sites of head and neck cancer.

  • NX - Regional lymph nodes cannot be assessed

  • N0 - No evidence of regional lymph node metastasis

  • N1 - Metastasis to a single ipsilateral lymph node measuring 3 cm or less in greatest diameter

  • N2 - Further divided into 3 categories

    • N2a - Single ipsilateral lymph node between 3 and 6 cm

    • N2b - Multiple ipsilateral lymph nodes less than 6 cm

    • N2c - Bilateral or contralateral lymph nodes less than 6 cm in greatest dimension

  • N3 - Lymph node greater than 6 cm

• Distant metastatic disease is divided into 2 categories.

  • M0 - Absence of distant disease

  • M1 - Presence of distant metastatic disease

• The T stage of a tumor indicates the extent of the primary tumor and varies by anatomic subsite. This can be measured by size, as in the oral cavity, oropharynx, and salivary glands; by involvement of varying subsites, as in the nasopharynx, hypopharynx, and larynx; or by extent of invasion and destruction, as in the maxillary sinus. Nevertheless, across all anatomic sites of the head and neck, the following classifications apply:

  • Stage I disease - Includes only T1 N0 M0 tumors

  • Stage II disease - Includes T2 N0 M0 tumors

  • Stage III disease - Includes T3 N0 M0 and T1-3 disease, which is N1 M0

  • Stage IV disease - Includes T4 tumors with or without nodal disease, as well as any tumor with N2 or N3 disease or evidence of distant metastatic disease

• The complexity of the staging system and its effect on prognosis obviously is somewhat convoluted. For example, in any given anatomic site, many different types of tumors can comprise a stage IV: anything from an extensive primary tumor without evidence of regional or distant metastatic disease to a very small primary tumor with bulky nodal disease. Therefore, the staging system is far from ideal but currently offers the best method of prognosticating a tumor.