Depth of invasion in patients with early stage oral cancer staged by sentinel node biopsy

Abstract

Background: To investigate if depth of invasion (DOI) can predict occult nodal disease in patients with cT1-2N0 (7th TNM) oral squamous cell carcinoma (OSCC) staged by sentinel lymph node biopsy (SLNB).

Methods: In 199 OSCC patients, DOI measurements and SLNB were performed.

Results: Metastases were found in 64 of 199 patients (32%). Of these 64 patients, the mean DOI was 6.6 mm compared to 4.7 mm in patients without metastases (P = .003). The ROC-curve showed an area under the curve of 0.65 with a most optimal cutoff point of 3.4 mm DOI (sensitivity 83% and specificity 47%). Regional metastases were found in 15% of patients with DOI ≤ 3.4 mm.

Conclusion: DOI seems to be a poor predictor for regional metastasis in patients with cT1-2N0 OSCC. Therefore, 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.

Keywords: Oral cancer; depth of invasion; lymph node metastases; sentinel lymph node biopsy.

Figure 1

Measuring depth of invasion from the deepest point of invasion—reconstructed basement membrane line in exophytic tumor (A) and ulcerative tumor (B) [Color figure can be viewed at wileyonlinelibrary.com]

Figure 2

ROC‐curve for prediction of presence of lymph node metastasis by depth of invasion, area under the curve of 0.65 [Color figure can be viewed at wileyonlinelibrary.com]

Figure 3

Distribution of nodal metastases per mm depth of invasion [Color figure can be viewed at wileyonlinelibrary.com]

Figure 4

Isolated regional disease‐free survival analysis with 7th and 8th TNM classification respectively. Comparison between pT1 vs pT2 in 8th TNM classification did not reach statistical significance (P = .231) [Color figure can be viewed at wileyonlinelibrary.com]