Intraoperative Depth of Invasion Is Accurate in Early-Stage Oral Cavity Squamous Cell Carcinoma

Abstract

Depth of invasion (DOI) is one predictor of nodal metastasis in oral cavity squamous cell carcinoma (OCSCC) and can facilitate the decision to complete an elective neck dissection (END) in early-stage disease with a clinically negative neck. The purpose of this study was to investigate the accuracy of DOI in intraoperative frozen specimens for T1N0 oral OCSCC. To compare the accuracy of DOI in frozen versus permanent specimens, we completed a prospective, blinded study of 30 patients with cT1N0 OCSCC who presented between October 2016 and December2017. DOI in frozen specimens was 96.8% accurate in predicting the need for END with a sensitivity of 90.9%, specificity of 100%, positive predictive value of 100%, and negative predictive value of 95.2%. A strong correlation was found between DOIs in frozen and permanent specimens measured by head and neck (HN) pathologists (r=0.96; 95% confidence interval [CI], 0.93 to 0.97), between HN pathologists using frozen specimens (r=0.98; 95% CI, 0.95 to 0.99) and permanent specimens (r=0.95; 95% CI, 0.91 to 0.98), and in DOIs in frozen specimens communicated intraoperatively versus measured by HN pathologist 1 (r=0.93; 95% CI, 0.86 to 0.97) and HN pathologist 2 (r=0.95; 95% CI, 0.89 to 0.98). Only 1 patient who did not undergo an END based on frozen specimens was undertreated owing to upgrading of the DOI in permanent specimens. DOI in intraoperative frozen sections has an accuracy of 96.8% and may be reliably used as a clinical tool to determine the need for END in early-stage OCSCC.