Sentinel lymph node biopsy in clinically N0 T1-T2 staged oral cancer: the Dutch multicenter trial.

OBJECTIVES: Results of the Dutch multi-institutional trial on sentinel lymph node (SLN) biopsy in oral cancer. PATIENTS AND METHODS: Patients were consecutively enrolled from 4 institutions, with T1/T2 oral cancer and cN0 neck based on palpation and ultrasound guided fine needle aspiration cytology. Lymphatic mapping consisted of preoperative lymphoscintigraphy. For intraoperative SLN detection a gamma-probe was used and in some patients additional blue dye. SLN negative patients were carefully observed, SLN positive patients were treated by neck dissection, radiotherapy or a combination of both. Endpoints of the study were risk of occult lymp node metastases, neck control, accuracy, 5-year disease-free survival (DFS), overall survival (OS) and disease-specific survival (DSS). RESULTS: Twenty of 62 patients (32%) had positive SLNs. Macrometastases were found in 9 patients, micrometastases in 8, and isolated tumour cells in 3 patients. Median follow-up was 52.5 months. Of the 42 SLN negative patients, 5 developed a regional recurrence of whom 4 patients could be successfully salvaged. DFS, OS and DSS of SLN negative patients were 72.0%, 92.7% and 97.4%, and for SLN positive patients these numbers were 73.7%, 79.7%, 85.0%, respectively (DFS: p=0.916, OS: p=0.134, DSS: p=0.059, respectively). Neck control rate was 97% in SLN negative and 95% in SLN positive patients. Sensitivity was 80% and negative predictive value 88%. CONCLUSION: SLN biopsy is able to reduce the risk of occult lymph node metastases in T1/T2 oral cancer patients from 40% to 8%, and enables excellent control of the neck.