Purpose: The purpose of this study was to evaluate the use of sentinel lymph node biopsy (SLNB) to correctly identify the presence or absence of nodal metastasis and to determine the outcomes of SLNB alone as the staging procedure in patients with clinically N0 oral squamous cell carcinoma.
Method: Fifty-nine patients who had T1/T2N0 oral squamous cell carcinoma (OSCC) were included in this study. All patients had the neck clinically staged by clinical exam and computed tomography. Patients with recurrence, history of radiation or chemotherapy were excluded from the study. Preoperative lymphoscintigraphy was performed after injecting the lesion with 99mTc-sulfur colloid and the sentinel lymph node(s) was identified with a hand held gamma probe. For the purpose of this study, patients were divided in two cohorts: Cohort A (N=38), SLNB with concurrent selective neck dissection clearing at least level I-III (SND); and Cohort B (N=21), SLNB alone. Main outcomes were sensitivity and negative predictive value of SLNB. Patients in Cohort B (21/59) who had negative results on SLNB were treated without neck dissection. These patients were observed clinically for recurrence rates, and disease-specific survival.
Result: Sentinel lymph nodes were successfully detected in all patients. In Cohort A (SLNB+ SND), of the thirty patients who had negative SLNBs, twenty-nine were found to have no positive nodes in the SND specimen, yielding a negative predictive value (NPV) of 96.7%, and specificity of 100%. In thirty-seven patients in Cohort A, SLNB’s correctly identified the status of the neck, with only one patient having a negative SLNB but a positive neck on SND, yielding a sensitivity of 88.9 %. Eight out of thirty-eight patients had positive nodes on both SLNB and SND with positive predictive value (PPV) of 100%. Three of these patients had additional positive nodes on the ND specimen. Five out of eight patients with positive nodes had T2 lesions the rest had T1 lesion. In cohort B (SLNB alone), twenty patients had negative sentinel nodes and did not undergo concurrent selective neck dissection, and one patient had metastatic disease a single sentinel lymph node, and subsequently underwent SND. The mean follows up was 2.83 years, with maximum of 5.27 years. So far there has been zero recurrence in this group
Conclusion: SLNB may accurately predict the status of the neck in clinically N0 necks of patients with early stage SCC of oral cavity.