Management of Positive Main Specimen Margin in Oral Tongue Cancer

Abstract

<h3>Purpose/Objective(s)</h3> While surgical margins are considered one of the most critical prognostic factors in the management of oral tongue cancer, controversy exists regarding the value of additional resection of a positive main specimen margin. Furthermore, the use of frozen sections is not standardized and varies amongst institutions. Our primary objective was to investigate the impact of immediate resection of a positive margin on local control of oral tongue cancer. A secondary objective was to evaluate the utility of tumor bed margins in predicting the status of the main specimen margin. <h3>Materials/Methods</h3> A retrospective analysis of all oral tongue cancers treated at a NCI-designated comprehensive cancer center between 2013 and 2018 was performed (n=273). Tumors were resected <i>en bloc</i>, and intraoperative frozen tumor bed margins were performed in most patients (n=256). The main specimen was inspected by the surgeon, and additional resection during the initial surgery was performed if deemed necessary by inspection of the main specimen and/or frozen sections. Positive margins were defined as invasive carcinoma or high-grade dysplasia at or < 1mm from the inked edge of the main specimen. Based on re-resection status, main specimen margins were further divided into the following groups: negative; positive with re-resection; and positive without re-resection. Cox proportional hazards models were first used to assess univariate associations between potential predictors and local recurrence free survival (RFS). Variables with <i>p</i><0.05 were then entered into multivariable models for RFS. The Kaplan-Meier estimate was used to calculate RFS rate. <h3>Results</h3> The rate of positive main specimen margin was 17.9% (49/273). Of the patients with positive margins, 38.8% (19/49) underwent immediate re-resection of the margin. Local recurrence rate was 7.7% (21/273). In the multivariable model, independent predictors of local recurrence included advanced T stage (T4a vs T1, HR 9.3 [95% CI 1.9-45.2], <i>p</i>=0.006) and positive margin without re-resection (vs negative margin, HR 2.8 [95% CI 1.0-7.7], <i>p</i>=0.041). Five-year RFS was 0.91 for patients with negative margins, 0.92 for positive margins with re-resection, and 0.73 for positive margins without re-resection. The rate of positive tumor bed frozen margin was 7% (18/256), and the sensitivity of intraoperative tumor bed margins in detecting a positive main specimen margin was 17.4% (8/46). <h3>Conclusion</h3> Our data demonstrates that, in patients with a positive main specimen margin, immediate targeted resection achieved local control rates comparable to patients with a negative margin. Without additional resection, positive margins were associated with poorer local control. Thus, intraoperative evaluation of the surgical margin with immediate targeted resection during the initial surgery plays a critical role in the management of oral tongue cancer.