Lung cancer has been the leading cause of cancer death among men in the United States for years, and since 1988, it has become the number-one cause of cancer death among women. An estimated 219,440 new cases of lung cancer are expected in 2009, and 159,390 deaths due to this disease are expected to occur, roughly 30% of all cancer deaths. This exceeds the combined number of deaths from the leading causes of cancer (breast, prostate, and colon cancers). It accounts for 6% of all deaths in the United States.

Lung cancer develops from pulmonary parenchymal or bronchial supportive tissues. Although multiple cell types are often found within a single lung tumor, one type usually predominates. Based on the therapeutic approach, there are two major subdivisions of lung cancer: small-cell lung cancer (SCLC), for which chemotherapy is the primary treatment, and non–small-cell lung cancer (NSCLC), which in its early stages (I and II) is treated primarily with surgery.

This chapter provides basic information on the epidemiology, etiology, screening, prevention, and signs and symptoms of lung cancer in general and then focuses specifically on the diagnosis, staging, pathology, and treatment of NSCLC and carcinoid tumors of the lungs, as well as the pulmonary evaluation of lung cancer patients and follow-up of long-term survivors.

Chapter 4 provides information on the staging, pathology and pathophysiology, and treatment of the far less common SCLC and concludes with brief discussions of mesothelioma and thymoma.

Epidemiology

Gender In the United States, the estimated number of new lung cancer cases for 2009 is 116,090 for men and 103,300 for women. Although the incidence of lung cancer had been rising in women, the rate of increase has begun to slow recently. The incidence is decreasing in men.

Age The age at which lung cancer patients are diagnosed varies widely, but the median age at diagnosis is approximately 70 years.

Race In the United States, the highest incidence of lung cancer in men and women is found in African Americans (107.6/100,000 for men and 54.9/100,000 for women) followed by Caucasians (79.3/100,000 for men and 54.9/100,000 for women).

Geography There are geographic variations in the incidence of lung cancer, with the highest rates worldwide observed in North America and Eastern Europe; in the United States, the highest rates are found in northern urban areas and along the southern coast from Texas to Florida. The state with the highest incidence of lung cancer is Kentucky, with an incidence of 136.2/100,000 in men and 76.2/100,000 in women.

Survival The overall 5-year survival rate for lung cancer is 15%, of which there has been a 1% improvement each decade for the past 30 years.

Etiology and risk factors

Cigarette smoking Approximately 87% of all cases of lung cancer are related to cigarette smoking. There is a relatively strong dose-response relationship between cigarette smoking and the development of this cancer. The greater the number of cigarettes smoked on a daily basis and the greater the number of years of smoking, the greater is the risk of lung cancer. An individual who smokes one pack of cigarettes daily has a 20-fold increased risk of lung cancer compared to a nonsmoker.

The overall incidence of cigarette smoking decreased from 1974 through 1992. Smoking cessation decreases the risk of lung cancer, but a significant decrease in risk does not occur until approximately 5 years of discontinuation, and the risk remains higher in former smokers than in nonsmokers for at least 25 years. The benefit of smoking cessation is greater if it occurs at a younger age.