Immunoprofiling in poorly differentiated non-small cell lung cancer, analysis of data in a tertiary care center

Background: Lung cancer is a leading cause of cancer-related deaths worldwide, including India, where it accounts for 5.9% of cancer cases and 8.1% of cancer-related mortality. Differentiating between major histologic subtypes of non-small cell lung carcinoma (NSCLC)-adenocarcinoma (ACA) and squamous cell carcinoma (SCC) is crucial due to significant differences in treatment response. Our study addresses the IHC profile of NSCLC in a tertiary care centre in South India. We have also deliberated whether a 2 panel IHC markers would be sufficient for the final diagnosis in a resource poor setting as compared to the traditional 4 IHC panel. Methods: A hospital-based cross-sectional study (2018-2022) analysed 319 histologically confirmed poorly differentiated NSCLC cases. IHC markers (TTF-1, Napsin A, p63 and p40) were used for subtyping per WHO classification. Staining patterns were semi-quantitatively scored against controls. Sensitivity, specificity, PPV, NPV, and overall accuracy were calculated. Data analysis was performed using SPSS v23. Results: Of the 319 cases, ACA was the most common (65.2%), followed by SCC (31.03%). Males accounted for 81.2% of cases, with the peak incidence in the 62-66 age group. For ACA, TTF-1 had higher sensitivity (97.17%) compared to Napsin A (83.49%), while Napsin A showed better specificity (96.04%). For SCC, p63 demonstrated higher sensitivity (93.07%) than p40 (78.22%), while p40 had better specificity (89.62%). Conclusions: The study highlights the need for tailoring the IHC panel to suit the histopathological specimen in order to clinch the final diagnosis. In finance effectiveness, two marker panel can also be used.