Despite advances in early detection, diagnosis, and treatment of oral squamous cell carcinoma (OSCC), the survival for patients with early stage remains at approximately 80% for the past 30 years. Regional lymph node metastasis is an important prognostic factor. Therefore, early detection of the cervical lymph nodes metastasis is expected to further improve survival. Sentinel lymph node biopsy (SLNB) is a widely accepted procedure in various human malignancies. In clinically N0 (cN0) early OSCC cases, SLNB has received considerable attention for its role in deciding whether to perform neck dissection. The objective in this study is to investigate the topographical distribution of sentinel lymph nodes (SLNs) and occult metastatic lymph nodes in early tongue squamous cell carcinoma (TSCC).
A total of 64 patients with T1/2N0 TSCC underwent SLNB between 2001 and 2016. The location of SLNs was determined by radioisotope (RI) method with preoperative lymphoscintigraphy and intraoperative use of a handheld gamma probe, and evaluated by histopathological and genetic examinations. Patients with metastatic lymph nodes were treated with completion neck dissection. Excised lymph nodes were grouped into the neck level according to the international guidelines.
SLNs were successfully identified with RI method (100%). The rate of SLN identified side was 84.5% in ipsilateral, 12.1% in bilateral, and 3.4% in contralateral. Nine of 64 patients (14.1%) had metastasis-positive SLN. Six patients with negative SLN developed the latent neck lymph node metastasis. There was no patients with metastatic involvement of neck level IV and V. The sensitivity, specificity, and accuracy was 60% (9/15), 100% (49/49), and 90.6% (58/64), respectively.
SLNB is a minimally invasive and highly reliable method staging the cN0 for patients with early OSCC. Completion neck dissection of level I-III in SLNB-positive patients might be sufficient in patients with early TSCC. Our study showed that SLNB was helpful in clarifying unexpected bilateral or contralateral metastatic drainage patterns. SLNB provides more accurate staging than elective neck dissection or wait and see policy.
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All authors have declared no conflicts of interest.