Pathophysiology
Clinical meaning
Lung cancer is the leading cause of cancer death worldwide. It is broadly classified as non-small cell lung cancer (NSCLC, ~85%) and small cell lung cancer (SCLC, ~15%). NSCLC includes adenocarcinoma, squamous cell carcinoma, and large cell carcinoma. Carcinogens (primarily cigarette smoke) cause DNA mutations leading to uncontrolled cell proliferation. Tumors can obstruct airways, invade surrounding structures, and metastasize to brain, bone, liver, and adrenal glands.