The prognostic impact of invasion patterns in squamous cell carcinomas of oral cavity

Aim: The aim of this study is to compare the histopathological worst pattern of invasion (WPOI) and tumor budding with other histopathological parameters, clinical data (recurrence, lymph node and distant metastasis) and overall survival in patients with oral cavity squamous cell carcinoma and evaluate these results with the data in the literature. Material and Methods: A total of 132 oral cavity and lip squamous cell carcinoma cases diagnosed between 2005 and 2021 with excisional biopsy selected for evaluation. Worst pattern of invasion (WPOI), tumor budding, cell nest size, stromal and epithelial lymphocyte infiltration, tumor stroma ratio, desmoplastic reaction type in the stroma, budding-depth of invasion score and stromal categorization score as well as classical histopathological parameters were evaluated on hematoxylin-eosin stained sections. Our results were compared with clinical data and overall survival. Also the invasion patterns and other histopathological features of lip and oral cavity SCCs were compared with each other. Results: Lip and oral cavity tumors were evaluated separately, since the survival rates and histopathological parameters related to the invasion pattern are different statistically in these tumor groups. Statistically significant worse overall survival was found in cases with 5 or more tumor budding, single cell invasion, low stromal and epithelial lymphocyte infiltration in lip and oral cavity SCCs. In addition, stroma rich tumors and tumors with immature stroma were also associated with worse overall survival in lip SCCs. While no correlation was found between WPOI and overall survival in the survival analyzes in both localizations, comparison between WPOI 4 and 5 was found to be associated with lymph node metastasis in oral cavity tumors. Conclusion: Our findings suggest that tumor budding, cell group size, stromal and epithelial lymphocyte infiltration might be included in the pathology reports of lip and oral cavity SCCs. However, these results need to be supported by studies that had larger cohorts with longer follow-up and meta-analyses. Keywords: Oral cavity squamous cell carcinoma, worst patern of invasion, tumour budding, cell nest size