Tumor-stroma ratio in preoperative biopsies and matched surgical specimens in oral squamous cell carcinoma: Concordance and impact on recurrence-free and overall survival

Stroma-richness is commonly associated with decreased survival times as well as advanced tumor stages in various malignant tumors. A previous study on laryngeal squamous cell carcinomas showed very good agreement for tumor-stroma ratio assessment between pre-treatment biopsies and resection specimens. We therefore aimed to determine whether similar results could be shown for oral squamous cell carcinomas. 107 preoperative biopsies and matched surgical specimens were obtained from the histological archive, dating from 2011-2022. Tumor-stroma ratio was determined on all samples and cases were divided into stroma-rich (≥50% stroma) and stroma-poor (<50% stroma). Results were then correlated with recurrence-free and overall survival. Tumor-stroma ratio showed substantial agreement between preoperative biopsies and surgical specimens with a kappa correlation coefficient of 0.643. Concerning preoperative biopsies, 28 cases were stroma-rich (26.2%), in the group of tumor resections, 32 cases were stroma-rich (29.9%). No association with either recurrence-free or overall survival could be shown for both groups (p-values 0.158-0.495). Concordance between pre-treatment biopsies and resections was substantial in our study, however, as no association with survival times could be demonstrated, the prognostic significance in our cohort remains unclear. This might be attributable to the fact that almost 75% of our patients presented with early-stage tumors, which sometimes seem to show a less pronounced prognostic effect of the tumor-stroma ratio.