Metastatic Squamous Neck Cancer With Occult Primary Treatment (PDQ®): Treatment - Health Professional Information [NCI]

General Information About Metastatic Squamous Neck Cancer With Occult Primary

Diagnosis

The diagnosis of an occult primary tumor is made only when no primary tumor is detected after careful search and when a primary tumor is not revealed during therapy. Patients with cervical lymph node metastases histologically related to a previously treated primary tumor and patients with lymphomas and adenocarcinoma are excluded from this diagnosis. If the biopsy is an undifferentiated carcinoma (in particular, a lymphoepithelioma), the most probable primary site is in the Waldeyer ring; for example, the nasopharynx, base of tongue, or tonsil. Most epidermoid carcinomas that are metastatic to lymph nodes of the upper half of the neck will originate from a head and neck primary site. Squamous carcinomas that are metastatic to the lower neck may represent a primary site in the head and neck, esophagus, lung, or genitourinary tract. A search for primary tumors in these areas must be undertaken before assuming that the primary is occult. Primary tumors arising in the nasopharynx may be secondary to Epstein-Barr virus (EBV) infection, and EBV genomic material may be detectable in cervical nodal tissue after DNA amplification using the polymerase chain reaction. Such a finding should lead to an in-depth search for a primary in the nasopharynx.[1]

The extent of investigation and type of treatment must be individualized depending on the patient's age and wishes, and on the site, histology, and extent of metastatic lymph node involvement of the tumor. A patient with a squamous carcinoma of the neck with occult primary should be checked for other obvious metastatic disease—for example, involving the lung, liver, or bone—because this would affect the locoregional approach to therapy.[2]

Survival

Three-year disease-free survival rates following surgery and/or radiation therapy for unknown squamous primary tumors range from 40% to 50% in patients with N1 disease to 38% and 26% for patients with N2 and N3 disease, respectively. Patients who later develop primary lesions have poor survival rates compared with patients whose primaries remain occult (30% vs. 60%).

Follow-Up

Patients with neck metastases from an undetectable primary should be given the benefit of definitive treatment. Despite the ominous situation of an undiscovered primary malignancy, a significant number of patients do achieve cure by both surgical and radiotherapeutic approaches. In some patients, long-term repeat examinations will eventually disclose the primary tumor, and at a treatable stage.

References:

1. Feinmesser R, Miyazaki I, Cheung R, et al.: Diagnosis of nasopharyngeal carcinoma by DNA amplification of tissue obtained by fine-needle aspiration. N Engl J Med 326 (1): 17-21, 1992.
2. de Braud F, al-Sarraf M: Diagnosis and management of squamous cell carcinoma of unknown primary tumor site of the neck. Semin Oncol 20 (3): 273-8, 1993.