Lung and Bronchus
New cases: An estimated 221,200 new cases of lung cancer are expected in 2015, accounting for about 13% of all cancer diagno- ses. The incidence rate has been declining since the mid-1980s in men, but only since the mid-2000s in women. From 2007 to 2011, lung cancer incidence rates decreased by 3.0% per year in men and by 2.2% per year in women.

Deaths: Lung cancer accounts for more deaths than any other cancer in both men and women. An estimated 158,040 deaths are expected to occur in 2015, accounting for about 27% of all cancer deaths. Death rates began declining in 1991 in men and in 2003 in women. From 2007 to 2011, rates decreased by 2.9% per year in men and by 1.9% per year in women. Gender differences in lung cancer mortality reflect historical differences in patterns of smoking uptake and cessation over the past several decades.

Signs and symptoms: Symptoms do not usually occur until the cancer is advanced, and may include persistent cough, sputum streaked with blood, chest pain, voice change, worsening short- ness of breath, and recurrent pneumonia or bronchitis.

Risk factors: Cigarette smoking is by far the most important risk factor for lung cancer; risk increases with both quantity and duration of smoking. Cigar and pipe smoking also increase risk. Exposure to radon gas released from soil and building materials is estimated to be the second-leading cause of lung cancer in the US. Other risk factors include occupational or environmental exposure to secondhand smoke, asbestos (particularly among smokers), certain metals (chromium, cadmium, arsenic), some organic chemicals, radiation, air pollution, and diesel exhaust. Additional occupational exposures that increase risk include rubber manufacturing, paving, roofing, painting, and chimney sweeping. Risk is also probably increased among people with a medical history of tuberculosis. Genetic susceptibility plays a contributing role in the development of lung cancer, especially in those who develop the disease at a young age.

Early detection: Screening with spiral CT has been shown to reduce lung cancer deaths by 16% to 20% compared to standard chest x-ray among adults with a 30 pack-year smoking history who were current smokers or had quit within 15 years. In January 2013, the American Cancer Society issued guidelines for the early detection of lung cancer based on a systematic review of the evi- dence. These guidelines endorse a process of shared decision making between clinicians who have access to high-volume, high-quality lung cancer screening programs and current or for- mer smokers who are 55 to 74 years of age, in good health, and with at least a 30 pack-year history of smoking. Shared decision making should include a discussion of the benefits,