Management of N0 neck in head and neck cancer: current controversies.

Squamous cell carcinomas of the upper aerodigestive tract are characterized by a high frequency of lymphogenic metastatic spread. The neck should be included in the treatment concept because almost 25% of all patients develop occult lymph node metastases. The only exception are early carcinomas of the lower lip and the vocal cords. Since currently for high risk patients no prognostic markers or other factors for occult metastatic spread are available, treatment strategies have to include the exact knowledge of direction and extent of regional lymphatic drainage. Based on this prerequisite, concepts for selective cervical lymph node dissection in case of the clinical N0 situation were developed which may also be used for an individually optimized radiotherapy. Intensity modulated radiotherapy (IMRT) bears a high potential for an optimized irradiation in case of potential occult metastatic spread of carcinomas of the upper aerodigestive tract. Without compromising local control rates IMRT allows a considerable reduction of permanent xerostomia by sparing at least one major salivary gland. The significant scientific purpose for the N0 neck, however, will remain the identification of high-risk patients, e.g. by means of tissue and/or serum-related markers, which carry a high risk of local and distant metastases.