How can lung cancer lead to repeated lower respiratory infections?

Lung cancer can lead to repeated lower respiratory infections primarily through the obstruction of the bronchi. When a tumour grows within or near the bronchial tubes, it can physically block the airway, preventing the normal clearance of secretions.1

This obstruction leads to the accumulation and stagnation of mucus and other fluids behind the blockage. This stagnant environment serves as an ideal medium for the growth of infectious organisms, which can result in recurrent infections such as pneumonia. Furthermore, chronic obstruction can cause the bronchial walls to lose their tone and undergo structural changes, a condition known as bronchiectasis. Once the bronchial architecture is damaged or dilated, the lungs' natural defense mechanisms are compromised, making it significantly easier for infections to spread and intensify, creating a cycle of persistent respiratory illness.1