Clinicopathological and Immunohistochemical Analysis of Lung Cancer Biopsies at a Tertiary Care Centre in Central Gujarat, India

Abstract

Introduction: Lung biopsy is a reliable and highly accurate tool for diagnosing and subtyping lung lesions. Two-thirds of lung cancer patients present with advanced disease, and small biopsies remain the main diagnostic tool. Histopathological and immunohistochemical examination of lung biopsies plays an important role in accurately diagnosing lung malignancies. Aim: The aim of present study was to analyse the clinicopathological and immunohistochemical features of lung cancer. Materials and Methods: This cross-sectional study was conducted in the Department of Pathology, Medical College, Baroda, over a period of two years and three months, from March 2019 to May 2021. A total of 53 cases of malignant lung cancer biopsies were included in this study. Clinical parameters, such as patient age, complaints, smoking history, clinical presentation, radiological findings, histopathology reports, and IHC findings, were retrieved. All cases underwent histopathological examination, and tumour typing was done according to the WHO classification 2021 of lung tumours. Immunohistochemistry (IHC) markers like CK5/6, CK7, TTF1, P63, synaptophysin, chromogranin, and pankeratin were used for further subtyping. Data analysis was done by Microsoft Excel 2019 spreadsheet. Results: A total of 53 cases of malignant lung cancer were included in this study. Of these, 38 (71.69%) cases were male, and 15 (28.30%) cases were female. 43 (81.13%) cases were over 50 years old, with a mean age of 61 years. After IHC, adenocarcinoma was seen in 27 cases (50.9%), followed by Squamous Cell Carcinoma (SCC) in 19 cases (35.8%), five cases of small cell carcinoma, one case of large cell neuroendocrine carcinoma, and one case of Non Small Cell Carcinoma-Not Otherwise Specified (NSCC-NOS). In adenocarcinoma, positivity for CK7, TTF1, and p63 was 100%, 74.07%, and 16.6%, respectively. In squamous cell carcinoma, positivity for CK5/6 and p63 was 100% and 78.94%, respectively. Conclusion: In the present study, the majority of cases were males. Adenocarcinoma was the most common subtype of Non Small Cell Lung Cancer (NSCLC). A panel of IHC markers is helpful in differentiating NSCLC into adenocarcinoma and squamous cell carcinoma on small true-cut lung biopsies. CK5/6 and p63 aid in detecting squamous cell carcinoma, while CK7 and TTF-1 help in detecting adenocarcinoma. The recommended immunohistochemical profile for NSCLC includes TTF1, CK5/6, CK7, and p63.