Oral squamous cell carcinoma with microscopic extracapsular spread in the cervical lymph nodes

The purpose of this study was to determine the detailed background of cases of oral squamous cell carcinoma (OSCC) with microscopic extracapsular spread (ECS) in the cervical lymph nodes. The cases of 78 patients with primary OSCC, who attended hospital from October 2007 to July 2011 and underwent resection of the primary tumour with neck dissection, were reviewed. The subjects were classified into three categories: pN0, pN+/ECS-, and pN+/ECS+; the outcomes of pN+/ECS+ patients were compared in detail with those of the other categories. Thirty-one cases (39.7%) were pN0, 25 cases (32.1%) were pN+/ECS-, and 22 cases (28.2%) were pN+/ECS+. The 3-year overall survival rate was 82.1% in pN0, 74.1% in pN+/ECS-, and 39.8% in pN+/ECS+ (pN0 vs. pN+/ECS+, P=0.0004; pN+/ECS- vs. pN+/ECS+, P=0.0086). The 3-year disease-specific survival rate was 96.2% in pN0, 77.2% in pN+/ECS-, and 39.8% in pN+/ECS+ (pN0 vs. pN+/ECS+, P<0.0001; pN+/ECS- vs. pN+/ECS+, P=0.0038). Patients with poorly differentiated carcinoma, those with three or more ECS+ nodes, and those with ECS+ node(s) located at levels III, IV, and V, had the worst prognosis among pN+/ECS+ subjects.