Prognostic Factors in Oral Squamous Cell Carcinoma: Systematic Review and Meta-Analysis

To evaluate current evidence on prognostic factors in oral squamous cell carcinomas (OSCCs), through a comprehensive meta-analysis of a total of 255 primary-level studies (63,114 patients).

MEDLINE, Embase, Web of Science, and Scopus were searched before January 2024. The risk of bias was analyzed using the Quality in Prognosis Studies tool.

Among the main influential parameters have been lymph node involvement in any of the measured forms, cN (overall survival: HR = 2.20, 95% CI = 1.98-2.45, p < 0.001; disease-specific survival: HR = 1.95, 95% CI = 1.44-2.65, p < 0.05; disease-free survival: HR = 2.13, 95% CI = 1.77-2.56, p < 0.001), pN (overall survival: HR = 2.04, 95% CI = 1.64-2.54, p < 0.001; disease-specific survival: HR = 2.83, 95% CI = 1.68-4.77, p < 0.001; disease-free survival: HR = 2.73, 95% CI = 1.96-3.81, p < 0.001) and extracapsular spread (overall survival: HR = 2.12, 95% CI = 1.81-2.47, p < 0.001; disease-specific survival: HR = 2.08, 95% CI = 1.43-3.03, p < 0.001; disease-free survival: HR = 2.27, 95% CI = 1.92-2.69, p < 0.001). In relation to the T-parameter, invasion depth greater than 5 mm strongly influenced mortality (overall survival: HR = 3.19, 95% CI = 1.74-5.84, p < 0.001; disease-free survival: HR = 1.97, 95% CI = 1.22-3.20, p = 0.006). The M parameter has been the most relevant negative prognostic factor-although with less robust results due to the lack of primary level studies: cM (overall survival: HR = 2.95, 95% CI = 2.09-4.17, p < 0.001; disease-specific survival: HR = 6.26, 95% CI = 1.54-25.42, p = 0.01; disease-free survival: HR = 2.78, 95% CI = 1.57-4.93, p < 0.001); pM (overall survival: HR = 5.19, 95% CI = 1.94-13.90, p = 0.01).

The risk of death and recurrence is increased if the diagnosis is achieved when the neck nodes are affected, the tumor is large, or has given rise to distant metastases, which points to the imperative need to implement measures for improving the early diagnosis of the disease by acting on all the actors responsible for the diagnostic delay of OSCC.