den Toom IJ, et al. - In this study, the authors investigated 199 oral squamous cell carcinoma (OSCC) patients to assess if the depth of invasion (DOI) could be a predicting factor for occult nodal disease in those with cT1-2N0 (7th TNM) OSCC staged by sentinel lymph node biopsy (SLNB). They observed metastases in 64 candidates (32%) with a mean DOI of 6.6 mm vs 4.7 mm in those without metastases. They found regional metastases among 15% of patients with DOI ≤ 3.4 mm. They suggested DOI is a poor predictor for regional metastases in these patients. Staging of the neck using SLNB in patients with early stage oral cancer should also be performed in tumors with limited DOI and probably in T3 (8th TNM) OSCC ≤4 cm diameter.