Impact of Margin Assessment Method on Adjuvant Therapy and Recurrence in Early Oral Cancer.

Abstract

To evaluate the impact of specimen-based margin (SBM) sampling versus tumor bed-based margin (TBBM) sampling on adjuvant therapy utilization and local recurrence rates in patients with early-stage oral cavity squamous cell carcinoma (OCSCC). We hypothesized that TBBM would be associated with increased use of adjuvant treatment and worse local control compared to SBM. In this retrospective, observational study, we reviewed records of patients with cT1 to T2, N0 OCSCC who underwent resection with intraoperative margin assessment at four academic centers between 2000 and 2019. Eligible cases required documentation of the margin sampling technique and at least two years of clinical follow-up. Local recurrence was the primary outcome, estimated using Aalen-Johansen cumulative incidence functions. Univariable and multivariable Fine-Gray subdistribution hazard models were used to identify associations, accounting for death as a competing risk and clustering by institution. The secondary outcome-adjuvant radiation therapy-was assessed using multivariable logistic regression. Among 646 eligible patients, there were no significant differences in reported closest margin distance between techniques. TBBM was associated with a significantly higher likelihood of receiving adjuvant therapy (HR 1.82, 95% CI 1.08-3.05, p = 0.024) and an increased risk of local recurrence (HR 1.72, 95% CI 1.00-2.95, p = 0.049) compared to SBM. In early-stage OCSCC, TBBM is linked to increased adjuvant therapy use and higher local recurrence despite similar margin clearance on final pathology. These findings suggest SBM may offer improved clinical outcomes through more accurate margin assessment.