Objective: The aims of this study are to evaluate the impact of frozen section in achieving adequate surgical margin and to study the accuracy of frozen section in detection of occult metastases.
Materials and methods: This was a retrospective review of prospectively collected data of 877 patients with squamous cell carcinoma of the tongue who underwent surgery and intra-operative frozen section at our center from January 2007 to June 2010.
Results: Frozen section was found to have very high accuracy in assessment of margin as well nodal status. On frozen section, 2% of our patients had positive margins and 21% had close margins. Most of these underwent intra-operative revision and at final pathology, 1.2% patients had positive margins and 11% were close. Of the 651 supraomohyoid neck dissections performed, one third were found to have occult metastases on frozen section. Of those reported positive on frozen section, 68% got additional removal of level 4 ± 5. Interestingly, 11% of these additionally removed nodes harbored metastases at final pathology. However, 7% of the patients were wrongly declared negative on frozen section. Tumor thickness was predictor of margin positivity as well as occult metastases. Tumor volume did not correlate with occult metastases or margin status.
Conclusions: Frozen section nearly halves the rates of positive margin and close margins which certainly translates into clinical benefits. The incidence of 11% positive nodes in the frozen section guided removal of lower levels is an important finding in our study that questions the ability of supraomohyoid neck dissection to completely eradicate the nodal burden in such patients.