Variability in pathologic interpretation of mandibular invasion

Objectives/Hypothesis Our objective was to identify the accuracy, sensitivity, and specificity of pathological interpretation of mandibular invasion by oral cavity squamous cell carcinoma (SCC) and compare the sensitivity of detecting mandibular invasion in the erosive versus the infiltrative patterns of invasion. We also aimed to describe the significance of the terminology the carcinoma “abuts the mandible” in pathologic interpretation of mandibular invasion. Study Design Retrospective case series. Methods Mandibulectomy specimens from patients who underwent surgical treatment for oral cavity SCC between January 1, 2005 and December 31, 2015 were retrospectively reviewed by a board‐certified anatomic pathologist. The accuracy of pathologic interpretation of mandibular invasion was calculated using the retrospective interpretation of bone invasion as the true interpretation, which was compared to the interpretation on the original pathology report. Incidence of encountering the terminology the carcinoma “abuts the mandible” in the pathology report was calculated. Results A series of 108 consecutive mandibulectomy specimens were reviewed. Sixty‐nine percent (74/108) of cases were interpreted as having mandibular invasion. The accuracy of interpreting mandibular invasion was 84%. The sensitivities for interpretation of mandibular invasion for the erosive and infiltrative patterns of invasion were 77% (30/39) and 91% (32/35), respectively (P = .08). Nine percent (10/108) of pathology reports utilized the terminology the carcinoma “abuts the mandible,” and 80% (8/10) of these cases exhibited mandibular invasion. Conclusions The accuracy of identifying mandibular invasion is 84%, indicating a certain degree of sampling error and variability in interpretation. A precise pathologic definition of mandibular invasion should be applied during the interpretation of these specimens to minimize variability. Level of Evidence 4 Laryngoscope, 130:1721–1724, 2020