LATE CERVICAL LYMPH NODE METASTASIS AFTER INTERSTITIAL BRACHYTHERAPY FOR STAGE I, II SQUAMOUS CELL CARCINOMA OF THE TONGUE

This study was conducted on 106 patients who received interstitial brachytherapy for Stage I, II squamous cell carcinoma of the tongue over the past 15 years and whose primary tumor was controlled. Late cervical lymph node metastasis occurred in 38 patients (35.8%), with the time until metastasis ranging from 2 months to 7 years and 8 months. Among the 38 patients, 34 patients underwent neck dissection and 23 of them could be salvaged. The 5-year disease-specific survival rate did not differ between stages T1 (73%) and T2 (62%). When classified according to the criteria of Yamamoto and Kohama of the mode of invasion, the 5-year survival rate was 100% in Grade 2, 96% in Grade 3, 63.1% in Grade 4C, and 0% in Grade 4D. The survival rate of Grade 4C and 4D differed from that of Grade 2 and 3. Patients with Stage I, II squamous cell carcinoma of the tongue and late cervical lymph node metastasis, regardless of their T-stage, had a 5-year survival rate of 65.6% and their prognosis was worse than that of metastasis-free patients who had a 5-year survival rate of 100%. During follow-up, early detection of late cervical lymph node metastasis by taking into consideration the mode of invasion is considered important.