Nodal metastases at level IIb during neck dissection for head and neck cancer: clinical and pathologic evaluation

Selective neck dissection as a part of an elective or therapeutic treatment of the neck is a common practice during the surgical treatment of patients with head and neck cancer. Recently, the need for routine dissection of level IIb has been discussed. The aim of this study was to verify the incidence of metastases at level IIb in patients with clinically negative necks (N0) and clinically positive necks (N+) and discuss the need for its excision.

A total of 114 patients with head and neck cancer undergoing neck dissection were prospectively analyzed. The total number of neck dissections analyzed was 148. The surgical specimens from each node level of the neck were pathologically diagnosed, with special attention to level IIb. Univariate associations between N classification and IIb positive cases were assessed using logistic regression and between IIa and IIb positive cases using Fisher exact test.

Of 148 neck dissections performed, level IIb resulted positive in 5 cases (3.3%): 1 patient with laryngeal cancer, 1 patient with oral cavity cancer, and 2 patients with oropharyngeal cancer, of which 1 underwent bilateral neck dissection. According to clinical N classification, for N0 and N+ the incidence of positive level IIb was 2% and 5%, respectively. All the cases with metastases at level IIb also showed metastases at level IIa. A statistically significant association between the presence of nodal metastases at level IIb and those at level IIa (p <.001) was found. The statistical association between N classification and IIb positive nodes only showed a trend toward significance (p = .06).

The incidence of metastases at level IIb is low, also in the N+ necks, therefore dissection of this level could be unnecessary in N0 necks. Furthermore, an interesting statistical association between the presence of metastases at level IIb and at level IIa was recorded.