Assessment and evaluate the eminence of depth of invasion in gingivobuccal sulcus carcinoma with the use of preoperative computed tomography and to compare it with depth of invasion measured histopathologically in the resected primary tumor, with the

Background: Depth of invasion (DOI) being one of the significant predictors in determining the prognosis of the disease, hence this data is available only post operatively but now with the advance technology we can assess DOI preoperatively. Here in our study, we used contrast enhanced computed tomography scan (CECT) to determine preoperative DOI. This measured data eventually helps the surgeon to plan resection of the oral primary tumor 3 dimensionally with safe margins. Methods: Prospective study was conducted between 2019 to 2021 with patients diagnosed with Gingivobuccal sulcus (GBS) carcinoma who were subjected for resection with neck dissection procedures. Preoperative CECT scan was performed to evaluate the depth of invasion (DOI). This was then compared with the DOI measured post operatively of resected specimen by histological assessment. A cut-off value for DOI was derived, beyond which nodal metastasis was evident. Results: Out of 51 patients 40 (78.4%) were male patients and 11 (21.6%) were female. Age ranged from 20 to 70 years. Preoperative DOI measured from CECT scan showed average value of 18.84 mm, with sensitivity of 100% which was highly statistically significant. Histopathological DOI showed average value of 7.26 mm. lowest DOI at which nodal metastasis observed was 3.4mm, so the cut-off value of DOI above which metastasis was probable decided was 3.5mm for this series. Conclusions: Hence CECT scan showed better sensitivity and specificity in determining early bony invasion in GBS carcinomas. Thus, making DOI a very reliable and predictable prognostic factor in oral GBS carcinoma.