Tumour depth of invasion of pT1 squamous cell carcinoma of the oral tongue and risk of pathologically detected neck metastases.

BACKGROUND: Tumour depth of invasion (TDI) is considered a predictor of pathologically detected neck metastases (PDNM) for squamous cell carcinoma (SCC), but different investigators have arrived at different cut-off of TDI. However, the relationship between TDI of pT1 SCC of the oral tongue and PDNM remains unknown. METHODS: Data was collected for patients with pT1SCC of the oral tongue. TDI, neurovascular invasion, pattern of invasion and presence of PDNM were recorded. The relationship between data was studied using logistic regression and ROC methods. RESULTS: With all other factors held constant, data showed that the odds ratio for each millimetre increase in TDI and risk of PDNM was 1.09 (95% CI: 0.95 - 1.25, p = 0.234), which was insignificant. CONCLUSION: TDI is not accurate and cannot be used as predictor of PDNM in patients with pT1 SCC of the tongue. Further, true TDI can only be assessed on resection specimens. This article is protected by copyright. All rights reserved.