Comparison of Intra-Operative Depth of Invasion Measurement by Frozen Section with Post-Operative Histopathology in Patient of Oral Cavity Squamous Cell Carcinoma.

Depth of Invasion (DOI) is an important and independent predictor for occult metastasis and recurrence. AJCC staging system (8th edition) has incorporated DOI in the staging of oral cancers. It is an essential parameter in deciding elective neck dissection. We hereby conducted a study to determine the accuracy of DOI in the frozen section as compared to the histological section in patients with T1N0 oral squamous cell carcinoma. This study was conducted over a period of 45 months in a tertiary care hospital. 31 patients with diagnosed Oral SCC and with T1N0 were enrolled. The intra-operative frozen section was done DOI was measured as per Cap protocol and compared with the DOI in the histopathological section. Strong correlation was found between DOI measured by frozen section and permanent section (r = 0.998; 95% CI, 0.999-0.997). The paired test showed a mean difference of 0.0066 mm (95% CI, - 0.0103-0.02346 mm;  = 0.096) between frozen section and permanent section. DOI measured was slightly higher in frozen section however this difference was neither statically nor clinically significant.This study shows the accuracy of frozen specimens in determining tumor DOI in T1N0M0 in oral cavity squamous cell carcinoma. Intraoperative DOI along with other factors may be used to determine the need for END (elective neck dissection) in early-stage oral cavity squamous cell carcinoma and thus avoid a staged operation or over- or under-treatment of the neck.