Indications for radiotherapy after neck dissection.

Up-front surgery and postoperative radiotherapy constitute a well-recognized treatment concept for locally or regionally advanced squamous cell carcinoma of the head and neck. This "treatment package" is further intensified with the concomitant application of chemotherapy during irradiation when high-risk features (ie, microscopically involved resection margins, extracapsular extension of the tumor from neck nodes, the presence of soft tissue deposits) are found on histopathologic examination of a resected specimen. With regard to neck disease, however, the demarcation line between low- and higher-risk clinical situations, which would differ with respect to the need for postoperative radiotherapy, is not clear. In an attempt to define the low-risk characteristics of disease in the neck that do not require adjuvant irradiation, we reviewed the available literature reports for any direct or indirect evidence on the value of postoperative radiotherapy in various clinical scenarios. The number of positive lymph nodes found in a dissected tissue specimen that should be used as a "cut-off" point for introduction of postoperative radiotherapy was evaluated in the context of both primary tumor characteristics and type of neck dissection.