Prognostic significance of extranodal extension in head and neck squamous cell carcinoma cN0 patients with occult metastatic neck nodes.

INTRODUCTION AND OBJECTIVES: Extranodal extension in nodal metastases is an independent adverse prognostic factor in head and neck squamous cell carcinoma patients. However, few studies specifically address the subgroup of patients with no clinical evidence of nodal disease.

MATERIAL AND METHODS: We retrospectively analysed data from 348 head and neck squamous cell carcinoma patients without any previous treatment and lacking clinical or radiological evidence of neck node metastases during the initial workup, treated with an elective neck dissection between 1992-2014. The incidence of occult metastatic neck nodes with extranodal extension and the impact of extranodal extension in survival were evaluated.

RESULTS: The proportion of patients with occult neck node metastases was 33%. Of these, 23.5% had at least one metastatic neck node with extranodal extension. There were significant differences in the disease-specific survival rate according to neck node status. Five-year disease-specific survival for patients without histopathological metastases was 90%, for patients with occult neck node metastases without extranodal extension it was 71.2%, and for patients with occult neck node metastases with extranodal extension it was 25.9% (P=.0001). The multivariate analysis revealed that the presence of occult node metastases with extranodal extension was the factor with strongest impact on survival. The inclusion of the extranodal extension as a criterion of histopathological evaluation in the 8th TNM classification edition improves the prognostic capacity compared to previous TNM editions.

CONCLUSIONS: Appearance of metastatic neck nodes with extranodal extension is an adverse prognostic factor in head and neck squamous cell carcinoma patients without clinical evidence of regional disease during the initial workup of the tumour.