Tumor depth of invasion and prognosis of early-stage oral squamous cell carcinoma: A meta-analysis.

Objectives: To assess the prognosis for early-stage oral squamous cell carcinoma according to tumor depth of invasion (DOI).
Methods: This study was logged in the PROSPERO database under protocol # CRD42017059976. The search was conducted in six electronic databases up to May 2019. Fixed-effects meta-analysis was performed for the calculation of the odds ratio (OR) and respective 95% CI. Primary outcomes were lymph node metastasis, recurrence, and survival. Heterogeneity was calculated by the I ² test. The certainty of evidence was assessed by Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) approach.
Results: Twenty-seven studies were included (19 in the meta-analysis) with 2,404 patients with a mean of 60 years of age. High tumor DOI is associated with a greater chance of presenting lymph node metastasis, regardless of the cutoff point for DOI (13 meta-analysis; OR 1.69-53.08), recurrence (five meta-analysis; OR 1.22-3.83), and lower chance of survival (1 meta-analysis; OR 0.49). The certainty of evidence varied from very low to low.
Conclusions: Tumor DOI is a good prognosticator for early-stage OSCC. The findings of the current meta-analysis highlight the clinical relevance of DOI and corroborate its incorporation for staging OSCC.
(© 2019 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd. All rights reserved.)