Squamous cell carcinoma metastatic to cervical lymph nodes from an unknown primary site: the impact of radiotherapy.

AIMS AND BACKGROUND: Cervical lymph node metastases of squamous cell carcinoma from an unknown primary site constitute about 5% of the total head and neck cancer, cases. The management of these patients is still a therapeutic challenge. The aim of the present study was to analyze the prognosis in a series of patients and, in particular, the impact of different radiotherapy techniques on the prognosis.

METHODS AND STUDY DESIGN: Data from 60 patients with cervical lymph node metastases of squamous cell carcinoma from an unknown primary site were reviewed. Nine of 60 patients (15.0%) received excisional biopsy. Radiotherapy was delivered to the bilateral neck and pharyngeal mucosa (extensive field) in 11 patients (18.3%), to the bilateral neck in 24 patients (40.0%), and to the ipsilateral neck in 25 patients (41.7%). Fourteen patients (23.3%) also received chemotherapy.

RESULTS: The 5-year overall survival rate of all patients was 68.5%. The overall survival of patients with N1, N2, and N3 stage was 100%, 68.0%, and 40.9%, respectively (P = 0.026). The overall survival of patients irradiated by ipsilateral neck, bilateral neck, and extensive field was 66.5%, 74.5%, and 54.6%, respectively (P = 0.5). At multivariate analysis, only N stage significantly affected overall survival (P = 0.032). The 5-year neck control rate of all patients was 65.6%. The neck control rate of patients with N1, N2, and N3 stage was 100%, 63.2%, and 34.6%, respectively (P = 0.064). The neck control rate of patients irradiated by ipsilateral neck, bilateral neck, and extensive field was 87.6%, 51.1%, and 72.7%, respectively (P = 0.279). Emergence of the occult primary was observed in 21.2% patients, and all of these occurred within the head and neck region. The primary tumor emerged in 23.3% of patients treated with ipsilateral and bilateral neck irradiation and in 12.5% of patients irradiated by extensive field (P = 0.469).

CONCLUSIONS: Patients with cervical lymph node metastases of squamous cell carcinoma from an unknown primary site have clinical features and a prognosis similar to those of other head and neck malignancies. Extensive irradiation results in a lower trend of emergence of the primary tumor than when patients are treated with ipsilateral and bilateral irradiation, but there is no significant difference in overall survival.