How many nodes are needed to stage a neck? A critical appraisal.

Reliable staging of the neck is an important factor for the estimation of prognosis of head and neck cancer patients. A total of 608 patients with oral squamous cell carcinomas treated from March 1975 to December 2000 were enrolled. In radical neck dissection (RND) group, the number of lymph nodes ranged from 6 to 116; while in selective neck dissection (SND) group, from 1 to 87 (P < 0.001). In SND group, the number of metastatic nodes ranged from 0 to 8 nodes, while in RND group, from 0 to 47 (P < 0.001). The number of dissected lymph nodes correlates with the presence of positive nodes (P = 0.001). In RND group, this correlation is described by the equation Y = -0.0117X (2) + 1.7262X. Factors affecting neck metastasis were number of dissected nodes (P < 0.001), lymphatic embolization (P = 0.044) and neural invasion (P = 0.030). In SND group, this equation is Y = -0.012X (2) + 1.5102X; the number of dissected nodes (P = 0.002) and lymphatic embolization (P = 0.001) were significant for metastasis finding. For patients with tumors at stages I and II, a significant impact on survival and neck recurrence rates were observed. In conclusion, we report the importance of the number of retrieved nodes in likelihood of positive cervical node finding. Node yield is an important factor in oral cancer staging, and, more important, in early stage carcinomas, it is associated with survival and recurrence rates.