Objectives: Although the reliability of frozen sections for the intraoperative assessment of complete tumour excision has been established, the best location for collection and the impact of the type of sampling are still debated. We retrospectively investigated the reliability of frozen sections when collected from the surgical bed as tissue strips representative of the whole superficial margin and as a bowl of tissue underlying the resection site for deep margin, and the possibility of relying on frozen section negativity to consider resections complete.
Materials and methods: Frozen section reliability was calculated by comparing histology before and after formalin embedding and then categorised by sampling type, in 182 patients undergoing transoral resection of oral cancer.
Results: Comparing frozen and permanent histology, sensitivity, specificity and accuracy were 69%, 98% and 96%, respectively; categorisation by sampling type failed to produce statistically significant differences. Based on frozen section negativity after formalin embedding, complete resections were obtained in 91.7% of patients with multiple-strip and bowl frozen sections.
Conclusion: Frozen sections collected as tissue strips and bowl are as reliable as point sampling in the intraoperative guidance of surgical resections. They effectively provide for margin enlargement, thereby increasing the surgeon's confidence that negative margins are clear.
Keywords: biopsy; frozen section; oral cancer; resection margins; shrinkage; transoral surgery.
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