Independent Prognostic Significance of Worst Pattern of Invasion-5 in Oral Squamous Cell Carcinoma Patients.

Background

Worst pattern of invasion-5 (WPOI-5) is a critical histologic feature in oral squamous cell carcinoma (OSCC) and is characterized by tumor satellite dispersion ≥1 mm; its independent prognostic value for disease-free survival (DFS) remains underexplored.

Purpose

The study purpose was to evaluate the role of WPOI-5 as an independent risk predictor for DFS in OSCC patients. STUDY DESIGN, SETTING, SAMPLE This retrospective cohort study of OSCC patients treated between 2017 and 2023 at a single institution (Chang Gung Memorial Hospital, Linkou, Taiwan). PREDICTOR VARIABLES The primary predictor was WPOI-5 versus WPOI-1-4. Secondary covariates included depth of invasion (DOI), perineural invasion, lymphovascular invasion, extra-nodal extension, and tumor staging. MAIN OUTCOME VARIABLE Primary outcome variable was DFS and the secondary outcome was overall survival (OS). COVARIATES The covariates collected for the study were age, length of follow up, and adjuvant treatment. ANALYSES Multivariable Cox regression modeling was used to compute hazard ratios for follow-up time to recurrence or death with 95% CIs. All factors with a bivariate significance of P < .05 were selected for the multivariate analysis using a conditional logistic regression model. Significance was determined at an alpha level of 0.05.

Results

187 subjects were included, with majority being male (89.3%, n = 167) and median age of 56 years (interquartile range: 19 years). The median follow up was 39.1 months with an interquartile range range of 40.7 months. WPOI-5 was observed in 15.5% (n = 29) of patients and statistically significant correlation with perineural invasion, lymphovascular invasion, DOI ≥10 mm, nodal metastasis, and extra-nodal extension was noted. The median DFS and OS were statistically significantly shorter in the WPOI-5 cohort compared to WPOI 1 to 4 (DFS: 34.3 vs 54.1 months, [P = .004]; OS: 44.5 vs 67.5 months, [P < .0001]). While WPOI-5 was not associated with prognosis in initial multivariate analysis, removing validated adverse pathologic variables revealed its significant association with DFS (hazard ratio 2.175; 95% CI, 1.047 to 4.517, P = .037).

Conclusion

AND RELEVANCE WPOI-5 appears to be an independent adverse prognostic factor for DFS in OSCC. Further studies are needed to evaluate its role in guiding adjuvant therapy and surveillance strategies.