How reliable are frozen sections in predicting the ultimate final margin status for head and neck (HN) squamous cell carcinomas?
Bottom line: Individual frozen section reads are highly accurate, but negative intraoperative margins do not guarantee margin-negative resections.
Background: Intraoperative frozen section assessment of surgical margins for HN squamous cell carcinomas is widely used, but surgeons, institutions, and pathologists use widely varying practices in how they sample tissue and process specimens. There is currently no consensus on how best to examine margins to maximize the utility of frozen sections.
Study design: Retrospective chart review of pathology reports from 437 surgical resections between 2010 and 2013.
Setting: Montefiore Medical Center Department of Otorhinolaryngology–Head and Neck Surgery, New York City.
Synopsis: Overall, frozen section margins had a sensitivity of 83.1% and a specificity of 97.9% for detecting positive final read, with an accuracy of 96.7%. The positive predictive value (PPV) was 77.9%, and the negative predictive value (NPV) was 98.5%. When close margins were grouped with positive margins, sensitivity decreased to 77.5%; specificity and accuracy remained high at 97.2% and 92.8%, respectively; PPV increased to 88.7%; and NPV decreased to 93.8%. Most discrepancies resulted from additional sections evaluated during permanent processing; only three reads were revised based on later examination of the original frozen slides. When overall margin status as assessed by intraoperative frozen reads was compared to final margin status, 34% had only negative margins reported throughout, while 22.9% had one or more positive or close margins on frozen read but a negative final overall margin. When close margins were grouped with negative margins, 73.5% had no positive margin intraoperatively or on final report; 11.1% had a positive margin intraoperatively that was ultimately cleared through additional margins. Limitations include the study’s retrospective nature, variations in handling of both frozen and permanent samples, and patient heterogeneity.
Citation: Du E, Ow TJ, Lo YT, et al. Refining the utility and role of frozen section in head and neck squamous cell carcinoma resection. Laryngoscope. 2016;126:1768-1775.