Oral Squamous Cell Carcinoma

To analyze the impact of resection margin status and histologic prognosticators on local recurrence (LR) and overall survival (OS) for patients with oral squamous cell carcinoma (OSCC). This study was both retrospective and prospective in design. Cohort 1 refers to the entire group of 292 patients with OSCC. The slides from the earliest resection specimens from Cohort 1 were examined in an exploratory manner for multiple parameters. Cohort 2 refers to a subset of 203 patients, who did not receive any neoadjuvant therapy and had outcome data. Cohort 3 represents a subset of Cohort 2 (n = 168) wherein the histologic resection margin status could be reconfirmed. Cohort 4 refers a subset of 85 patients with tongue/floor of mouth tumors. Margin status was designated as follows: group 1, clearance of ≥5 mm with intraoperative analysis, no need for supplemental margins (n = 46); group 2, initial margins were measured as 1 mm) was associated with LR (P = 0.005) and OS (P = 0.039). Limited lymphocytic response was also significantly associated with LR (P = 0.005) and OS (P = 0.001). When used as covariates in a multivariate Cox regression model, worst pattern of invasion, perineural invasion, and lymphocytic response were significant and independent predictors of both LR and OS, even when adjusting for margin status. Thus, these factors were used to generate our risk assessment. Our risk assessment classified patients into low-, intermediate-, or high-risk groups, with respect to LR (P = 0.0004) and OS (P < 0.0001). This classification retained significance when examining patients with uniform treatment. In separate analyses for each risk group, we found that administration of adjuvant radiation therapy is associated with increased local disease-free survival for high-risk patients only (P = 0.0296) but not low-risk or intermediate-risk patients. Resection margin status alone is not an independent predictor of LR and cannot be the sole variable in the decision-making process regarding adjuvant radiation therapy. We suggest that the recommendation for adjuvant radiation therapy be based on, not only traditional factors (inadequate margin, perineural invasion, bone invasion) but also histologic risk assessment. If clinicians want to avoid the debilitation of adjuvant radiation therapy, then a 5-mm margin standard may not be effective in the presence of high-risk score.