Radiotherapy for the clinically negative neck in supraglottic laryngeal cancer

The supraglottic larynx has rich lymphatic drainage, resulting in a high incidence of occult cervical metastases, and the optimal treatment of the clinically uninvolved neck in supraglottic laryngeal cancer remains controversial. Selected retrospective series report a greater than 20% regional failure after treatment by radiotherapy alone, and some investigators recommend routine prophylactic neck dissection. We report on our series of patients who received radiotherapy as sole treatment to the clinically negative neck, either to the bilateral neck for N0 disease or to the contralateral neck for ipsilateral lymphatic involvement.

Between 1971 and 1998, 150 patients with supraglottic laryngeal cancer received radiotherapy alone to the clinically negative neck. Fifty-two patients had ipsilateral lymph node metastases (N1 = 16, N2a = 12, N2b = 20, N3 = 4), and 98 patients had no clinical nodal involvement. The primary site (T1/T2 = 74, T3/T4 = 76) was treated with radiotherapy (N = 91) or laryngectomy plus radiotherapy (N = 59). Neck dissection was performed on the involved neck in 36/52 node-positive patients for either multiple involved nodes (N = 20) or size > 3 cm (N = 16). Radiotherapy was delivered in standard fractionation and field arrangement. The median dose to the clinically negative neck was 5000 cGy (range: 4860-6000 cGy).

With a median follow-up of 48 months, the clinically negative neck was the first site of failure in 3.3% of patients. The contralateral neck remained disease free in all patients. Five failures occurred in the N0 neck, and the median time to recurrence was 12 months (range: 5-30 months). Salvage therapy was neck dissection for the N0 neck failures. The 5-year locoregional control, disease-specific survival, and overall survival were 69%, 74%, and 61%, respectively.

Our data support the use of radiotherapy as a prophylactic treatment for the clinically negative neck. Tumor control in the clinically uninvolved cervical lymphatics is comparable to that in surgical series, suggesting that routine neck dissection may not be necessary. Prospective trials are necessary to further define the role of radiotherapy in this patient population.