AbstractAimsDifferent regions of oral squamous cell carcinoma (OSCC) have particular histopathological characteristics, and the individual histological characteristics of the tumors are poorly understood. Therefore, calculating the proportion of tumor cells in different regions that allow assessment of the prognostic outcomes for OSCC patients would be of great clinical significance.Methods and ResultsWe established an open‐source software‐based analytic pipeline that defines the inner tumor and invasive tumor front (ITF) in pancytokeratin‐stained whole slide images (WSIs) and quantifies the tumor‐stroma ratio (TSR) within the two regions. We applied this method to 114 patients with OSCC and predicted patient prognosis by the TSR. The proportion of tumor area in the inner tumor was generally higher than that in the ITF (p< 0.0001). TSR was an independent prognostic factor for overall survival (OS) (p= 0.016), disease‐free survival (DFS) (p= 0.026), and relapse‐free survival (RFS) (p= 0.037) in inner tumor, and TSR was an independent prognostic factor for OS (p= 0.00052), DFS (p= 0.035), and metastasis‐free survival (MFS) (p= 0.038) in the ITF. Tumor‐low status was associated with poorer prognosis. There was a significant correlation between the TSR and perineural invasion (PNI) in the inner tumor (p= 0.009).ConclusionsThe histopathological characteristics of different regions of OSCC may be used to develop the potential prognostic markers. The TSR of the inner tumor is more targeted in predicting prognosis and accurately assesses the risk of PNI+.