Clinicopathological Parameters and Immunohistochemical Expression of EGFR in Colorectal Carcinoma: A Cross-sectional Study

Abstract

Introduction: Colorectal Carcinoma (CRC) is the third most common type of cancer worldwide and is one of the leading causes of cancer-related death. Adenocarcinoma is the most common type. Histopathological examination is necessary to determine the type and extent of the tumour, which is essential for patient management and prognosis. Molecular markers play a major role in CRC, among which Epidermal Growth Factor Receptor (EGFR) has prognostic significance. Aim: The aim of this study was to evaluate the immunohistochemical expression of EGFR in cases of colonic carcinoma and analyse its relationship with various histological and clinical parameters. Materials and Methods: An observational (cross-sectional) study was conducted in the Department of Pathology, Sree Mookambika Institute of Medical Sciences, Kulasekharam, Kanyakumari district, Tamil Nadu, India. Data from colonic carcinoma patients confirmed by Haematoxylin and Eosin (H&E) staining were collected over a three-year period from January 2019 to December 2021. A total of 58 cases were included. The characteristics studied included age, sex, Carcinoembryonic Antigen (CEA) levels, tumour site, size, degree of histological differentiation (well, moderate, poor), TNM staging, and lymph node status. The EGFR score was obtained by multiplying the grade (% positive cells) by the intensity, and a composite score ranging from 0 to 9 was obtained. This score was used to define low EGFR expression (<6) or high EGFR expression (>6). Analysis was performed using the Chi-square test in Statistical Package for the Social Sciences (SPSS) version 20.0. Results: Among the 58 patients included in the study, the most common age group affected by CRC was 61 to 70 years (28 cases; 48.3%), with a mean age of 63.32±14.36 years. The most common histological variant was low-grade adenocarcinoma (47 cases; 81.03%). EGFR reactivity was positive in 50 patients (86.20%). EGFR overexpression was significantly associated with histopathological type (low-grade adenocarcinoma) and tumour stage, with p-values of 0.03 and 0.001, respectively. Conclusion: Immunohistochemical overexpression of EGFR in CRC is associated with histopathological type and tumour staging in this study. This overexpression is associated with poor prognosis and can be used as a predictive marker for patients who yield positive results with chemotherapy.