Neck dissection for unknown cancer of the head and neck in the era of chemoradiation.

PURPOSE: To report outcomes for patients with cervical lymph node metastases from an unknown primary site of the head and neck treated with either non-operative therapy or neck dissection followed by adjuvant therapy.

MATERIALS AND METHODS: All patients with squamous cell carcinoma of an unknown primary site of the head or neck seen between 2003 and 2013 were reviewed. The Kaplan-Meier method was used to estimate overall survival, local recurrence free survival, loco-regional recurrence free survival, and progression free survival. The log-rank test and proportional hazards regression were used to analyze factors influencing outcomes.

RESULTS: Of 2258 patients with a new diagnosis of head and neck cancer, no primary site was identified in 66 patients. Twenty-nine patients were treated with definitive non-operative therapy (15 with chemoradiation and 14 with radiation alone). Thirty-seven patients received an upfront neck dissection followed by adjuvant radiation or chemoradiation. Three-year loco-regional recurrence free survival, progression free survival, and overall survival were 55.9%, 55.4%, and 69.4% respectively. Patients treated with preoperative neck dissection had improved local recurrence free survival (96.7% vs 54.1%, p=0.003) and loco-regional recurrence free survival (82.2% vs 46.4%, p=0.068) compared to patients treated with definitive chemoradiation with no difference in overall survival (p=0.641).

CONCLUSIONS: Neck dissection improved local and regional control but not overall survival in patients with unknown primary squamous cell carcinoma of the head and neck over non-operative therapy alone.