Histological subtype and tumour differentiation as predictors of survival among patients with non-small cell lung cancer in specialised hospitals in Ethiopia

Abstract

Introduction: non-small cell lung cancer accounts for most lung cancer-related deaths worldwide. Although tumour-node-metastasis staging remains the cornerstone of prognostication, histological subtype and tumour differentiation may provide additional prognostic value, particularly in low- and middle-income countries where advanced molecular testing is limited. Evidence on these factors in Ethiopia is scarce. Methods: an institution-based retrospective cohort study was conducted among 202 adult patients who received follow-up care at three specialised hospitals in Ethiopia between January 2020 and January 2025. Data were extracted from medical records and supplemented with telephone follow-up to ascertain survival outcomes. Overall survival was estimated using the Kaplan-Meier method, and Cox proportional hazards regression models were applied to identify independent predictors of mortality, with statistical significance set at p < 0.05. Results: the median overall survival was 10 months. Patients with squamous cell carcinoma had significantly better survival than those with non-squamous cell carcinoma (log-rank p = 0.020). Survival also differed significantly by histological differentiation (log-rank p = 0.001). In multivariate analysis, advanced primary tumour stage, contralateral nodal involvement, distant metastasis, non-squamous histology, moderately or poorly differentiated /undifferentiated tumours, and poor performance status were independently associated with worse survival. Similarly, Patients aged 40-59 years and ≥ 60 years had significantly lower hazards of death compared with patients aged under 40 years. Conclusion: histological subtype and tumour differentiation are independent predictors of survival among NSCLC patients in Ethiopia, beyond conventional TNM staging. These findings provide context-specific evidence from an Ethiopian cohort, where advanced molecular profiling is limited, and highlight the prognostic value of routinely available histopathological features in guiding clinical decision-making in resource-constrained settings.