Evaluation of elective neck dissection in patients with clinical stage T2N0 tongue cancer

There are various indications for neck dissection for early tongue cancer. We do not perform elective neck dissection at the time of excision of the primary tumor for T2N0 tongue cancer. This study examined the incidence of local recurrence and late cervical lymph node metastasis in relation to the thickness of invasion of T2N0 tongue cancers. We also present a treatment plan for neck lymph nodes in T2N0 tongue cancers. The subjects were 26 patients with T2N0 tongue cancer being treated by surgery for the first time (2004-2014). Their clinic-pathological data were retrospectively reviewed. The 5-year overall survival rate was 86.5%. Local recurrence occurred in 7.7%(2/26 cases). Late cervical metastasis occurred in 42.3%(11/26 cases) of the patients. Neck dissection was performed in these cases, and there was no neck recurrence in any of them. Two patients died because of lung metastases afterwards. The pathological sites of cervical metastases were all in the area of level I to III. The rate of metastases in level I, level II, and level III was 50.0%, 80.0%, 30.0%, respectively. The incidence of cervical metastasis after partial glossectomy was 71.4%(10/14 cases) for patients with tumor thickness 4 mm and 0% (0/6 cases) for patients with thickness ＜ 2 mm. The average thickness of invasion was 6.7±3.1mm with late cervical metastasis, and 2.9±3.2mm without metastasis (p ＜ 0.01). As a medical treatment for T2N0 tongue cancer, we consider that elective neck dissection should be performed in cases with tumor thickness ≥ 4 mm.