Sentinel node biopsy for oral cancer: A prospective multicenter Phase II trial

A recent study identified a survival benefit with prophylactic neck dissection (ND) at the time of primary surgery as compared with watchful waiting followed by therapeutic neck dissection for nodal relapse, in patients with cN0 oral squamous cell carcinoma (OSCC). Alternative management of cN0 neck cancer is recommended to minimize the adverse effects of ND, indicating the need for sentinel node biopsy (SNB) and limited neck dissection. We conducted a multicenter Phase II study to examine the feasibility of SNB for clinically N0 OSCC.

Previously untreated N0 OSCC patients (n=57) with clinical late-T2 or T3 tumors were enrolled across 10 institutions. SNB navigated with multislice frozen section analysis of sentinel nodes (SNs) and SNB supported sentinel node lymphatic basin dissection (SN basin dissection) were performed in a one-stage procedure. The endpoint was to investigate the rate of false-negative metastases after SN basin dissection and SNB alone.

Most tumors were late-T2 lesions (n=50; 87.7%). SNs were identified in all patients. A total of 196 SNs were detected. Among these SNs, 35 (17.8%) were positive for metastasis (9 in level I, 12 in level II, 12 in level III, 1 in level V and 2 in the contralateral region of the neck). The false-negative rate of SNB supported by SN basin dissection and SNB alone was 4.5% and 9.1%, respectively. The concordance of the SN status in intraoperative frozen sections with the permanent histopathology was 97.4% (191/196). The sensitivity and specificity of intraoperative pathological evaluation were 85.7% (30/35) and 100% (30/30), respectively. The 3-year overall survival (OS) and disease-free survival was 89.5% and 82.5%, respectively. The OS of SN-negative patients was significantly longer than that of SN-positive patients (P=0.047).

The current study verified that SN basin dissection was a useful back-up procedure for SNB performed as a one-stage procedure, showing a low false-negative rate. SNB alone is an appropriate staging method for patients with clinical N0 staging, and a reliable procedure to determine the appropriate levels for neck dissection.