Prognostic Role of Worst Pattern of Invasion in Oral Squamous Cell Carcinoma

<b>Background/Objectives</b>: The pattern of invasion describes the arrangement of neoplastic cells along the tumor infiltrative front and refers to the way cancer infiltrates tissue at the tumor/host interface. Accumulating evidence suggested that the Worst Pattern of Invasion (WPOI) represents an independent prognostic factor in oral squamous cell carcinoma (OSCC). However, it is still considered a minor prognostic criterion, and it is recommended as an optional report component in the College of American Pathologists (CAP) guideline. <b>Methods</b>: Therefore, the study aims to extensively review the literature data regarding the prognostic role of the WPOI in OSCC. <b>Results</b>: The WPOI resulted as an independent prognostic factor for locoregional recurrences (LRRs), lymph node metastasis (LMN), overall survival (OS), disease-specific survival (DSS), and bone tissue infiltration, regardless of the oral subsite and the pathological stage. Moreover, several authors suggested the evaluation of the WPOI to lead the postoperative management and to determine the occult LNM in early-stage OSCC. <b>Conclusions</b>: The prognostic relevance of the WPOI in OSCC highlights its evaluation in pathological daily practice. Therefore, the WPOI-detection method and scoring system should be validated based on the tumor stage and site.