To Assess the Interobserver Variability in Mitotic Figure Counting in Various Grades of Oral Squamous Cell Carcinoma

Abstract

Background: Oral squamous cell carcinoma (OSCC) is the most common oral malignancy, representing up to 80–90% of all malignant neoplasms of the oral cavity. The increasing cases of oral cancer are the most important concern for community health. Defects of mitosis result in various nuclear abnormalities namely micronuclei, binucleation, broken egg appearance, pyknotic nuclei, and increased numbers of mitotic figures. The rationale for mitotic counting is that it is frequently used for classification and grading of tumors, prediction of prognosis of tumors and even advocated as a decision point for treatment. Reproducibility of the mitotic counting is paramount for the assessment of malignancy on a histologic scale. Considering this, we decided to assess the inter-observer variability in mitotic figure counting in various grades of oral squamous cell carcinoma. Material Methods: A retrospective study was carried out on 48 formalin fixed paraffin embedded tissue blocks of the confirmed cases of Oral squamous cell carcinoma in the archives of department of oral pathology, Govt. Dental College Hospital, Srinagar. Mitotic figure counting was done by two independent, mutually blind observers. The data was assessed for inter-observer variability in counting of figures. Results: Least difference was seen in cases of WDSCC up to the maximum difference of 3 mitoses. MDSCC showed modest differences in observations, with a maximum difference of 4 mitoses. PDSCC cases had the highest inter-observer variability, with a maximum difference of 5 mitoses. Conclusion: Mitosis counting has been shown most convincingly to provide independent prognostic value and is the most well established component of the histological grading systems of OSCC. Reproducibility of the mitotic counting is paramount for the assessment of malignancy on a histologic scale.