Postoperative elective nodal irradiation for squamous cell carcinoma of the head and neck: outcome and prognostic factors for regional recurrence.

BACKGROUND This study describes the results of elective irradiation in the N0 neck and tries to identify prognostic factors for regional recurrence. MATERIALS AND METHODS Between 1985 and 2000, 785 cN0 or pN0 necks were treated with elective nodal irradiation in 619 head and neck squamous cell carcinoma patients. RESULTS Regional control at 3 years was 94% in the cN0 (nondissected) neck compared with 97% in the pN0 (dissected) neck and 90% in the ipsilateral compared with 96% in the contralateral neck (P = 0.08 and P = 0.006, respectively). Regional control in the ipsilateral cN0 neck was 78% compared with 96% in the contralateral cN0 neck. Surgical margin of the primary tumor was an additional prognostic factor in all N0 and pN0 necks. CONCLUSIONS Neck control rates in electively irradiated N0 necks were excellent. Regional control was worse in the cN0 neck compared with the pN0 neck and in the ipsilateral neck compared with the contralateral side. Additionally, in case of positive surgical margins of the primary tumor, elective nodal irradiation should be applied, even in case of a pN0 neck.