How can a smoker die from "lung cancer"?

Deadly cancer: Lung cancer develops by abnormal cells multiplying with uncontrolled growth in affected lung.There are several different cell types of cancer. Metastases or spread can occur to many different parts of body.Primary lung cancers themselves most commonly metastasize to the brain, bones, liver, and adrenal glands. Only 15% 5 year survival. Patients die from overwhelming uncontrollable disease.

Breathless: Frequently pulmonary obstructive symptoms, just cannot breathe, or pneumonia, and fever and sepsis, or metastatic disease in a critical area- brain for example, or the chest fills with fluid, one can break alone- hip and fall due to metastasis.