From our database of 351 primary oral carcinomas, we selected all pT1-2 tumours (n = 246). Infiltration depth was measured in 212 cases. Neck status was determined by histopathological examination of the dissection specimen, or by at least two years of follow-up.
Mean infiltration depth was 5.49 mm (95%CI: 4.86-6.12) in the N0 and 8.40 mm (95%CI: 7.38-9.43) in the N+ group (p < 0.001). cN status, lymphovascular invasion and infiltration depth were the only independent predictors for nodal status in multiple logistic regression. ROC-analysis on pT1cN0 tumours resulted in an optimal cut-off for the prediction of the nodal status at a depth of 4.59 mm. This cut-off identified a subgroup of patients at increased risk for nodal metastasis (OR = 8.3) and with significantly shorter survival.
Tumour infiltration depth is an independent predictor for nodal status in pT1-2 OSCC. In pT1cN0 tumours, a cut-off at 4.59 mm results in the best predictive value.
We recommend an infiltration depth of 猢? mm as an indication to perform a neck dissection in pT1cN0 OSCC.