Assessment of frozen section margin analysis during olfactory neuroblastoma surgery

Objectives: 1) assess the performance of the intraoperative frozen section procedure to correctly classify biopsies obtained during olfactory neuroblastoma (ONB) surgery; 2) define the relationship between posttest probabilities and pretest probabilities from frozen section analysis; and 3) review incorrectly classified specimens. Study Design: Study of diagnostic accuracy. Methods: We searched our institution's pathology database for patients who had ONB surgery between January 1, 2000 and November 16, 2012. We only included patients who had a definitive diagnosis of ONB prior to surgery and frozen sections obtained during surgery. All frozen sections in this study had corresponding permanent sections available to serve as a gold standard. This database was analyzed to obtain classification statistics. The confidence intervals for classification performance were obtained using the bootstrap sampling method. Confidence intervals for posttest probability curves were derived using the Taylor series expansion. Finally, we obtained and reviewed the slides from ambiguous or incorrect reads. Results: A total of 459 specimens from 33 patients were analyzed. We found the following performance characteristics: sensitivity: 0.89 (0.81, 0.94); specificity: 0.96 (0.94, 0.98); accuracy: 0.95 (0.92, 0.96); likelihood ratio positive: 24.4 (14.5, 44.1); prevalence: 0.20 (0.17, 0.25); positive predictive value: 0.86 (0.78, 0.92); and negative predictive value: 0.97 (0.95, 0.99). Histopathologic review revealed that crush artifacts and inadequate specimen size were major sources of incorrect reads. Conclusion: We found frozen section assessment of ONB specimens to be an excellent tool for the assessment of intraoperative margins. Level of Evidence: NA. Laryngoscope, 127:1735–1741, 2017.