Lung Carcinoma

Lung carcinoma is a malignant lung tumor usually categorized as small cell or non–small cell. Cigarette smoking is the major risk factor for most types. Symptoms include cough, chest discomfort, and, less commonly, hemoptysis, but many patients are asymptomatic and some present with metastatic disease. Diagnosis is suspected by chest x-ray or CT scan and confirmed by biopsy. Treatment is with surgery, chemotherapy, and/or radiation therapy. Despite advances in treatment, the prognosis is poor, and attention is focused on early detection and prevention.

Epidemiology, Pathophysiology, and Classification

An estimated 171,900 new cases of lung carcinoma are diagnosed each year in the US, and the disease causes 157,200 deaths annually. The incidence is rising in women and appears to be leveling off in men. Black men are at especially high risk.

Cigarette smoking, including passive (secondhand) smoking, is the most important cause. Risk differs by age and smoking intensity and duration; risk after smoking cessation declines but probably never returns to baseline. Exposure to radon, a breakdown product of naturally occurring radium and uranium, is the most important environmental risk factor in nonsmokers.