Histopathological Patterns of Lung Cancer and Its Clinical Correlation: A Retrospective Study

Abstract

Background: Lung cancer remains a formidable global health challenge and is one of the leading causes of cancer-related mortality in India. The accurate and timely histopathological subtyping of lung tumors is critical, as therapeutic strategies are increasingly tailored to specific histological types. Global and national epidemiological patterns suggest a recent shift in the predominant histological subtype from squamous cell carcinoma (SCC) to adenocarcinoma (ADC). Understanding the current local distribution and clinical correlations is vital for optimizing regional health resource allocation and prevention efforts.

Objectives: This retrospective study aimed to analyze the spectrum and relative distribution of primary lung cancer histological subtypes diagnosed at a tertiary care center in North India between November 2022 and April 2023. A secondary objective was to correlate the observed histopathological patterns with key clinical and demographic factors, including age, sex, smoking status, and clinical stage at presentation.

Methods: A retrospective descriptive and analytical study was conducted using the archived pathology reports and medical records from the Shri Guru Ram Rai Institute of Medical & Health Sciences, Dehradun, India, covering the period from November 1, 2022, to April 30, 2023. A total of 185 patients with histologically confirmed primary lung malignancy were included. Data encompassing demographics, smoking history, Eastern Cooperative Oncology Group Performance Status (ECOG PS), and clinical stage were collected using a standardized proforma. Associations between categorical variables and histological subtypes were tested using the Chi-square test. Prognostic factors were evaluated using Univariate and Multivariate Cox Proportional Hazards Regression modeling.

Results: The final cohort (N=185) exhibited a median age of 61.0 years, with a male-to-female ratio of 2.5:1. Non-Small Cell Lung Carcinoma (NSCLC) accounted for 85.9% of cases. Adenocarcinoma was the most frequently identified subtype (44.3%), followed by SCC (34.1%), and Small Cell Lung Carcinoma (SCLC) (14.1%). A highly significant association was noted between histology and sex (P<0.001), with ADC being predominant in females and never-smokers, while SCC showed a marked association with male sex and heavy smoking history. Advanced stage (Stage IV) presentation was observed in 48.6% of the cohort. Multivariate analysis identified Stage IV disease (Adjusted HR: 2.90, 95% CI 2.30–3.65; P<0.001) and poor ECOG PS (>1) (Adjusted HR: 1.75; P=0.001) as the strongest independent predictors of poor hypothetical short-term progression.

Conclusions: Adenocarcinoma has confirmed its position as the predominant histological subtype in this regional cohort, validating the observed national epidemiological shift. Histological subtyping demonstrates clear correlations with demographic and environmental risk factors. However, the high incidence of late-stage presentation indicates that clinical variables, specifically Stage and Performance Status, remain the dominant determinants of early prognosis in this population.