Cigarette smoking is by far the most important risk factor for lung cancer; 81% of lung cancer deaths in the US are still caused by smoking. Risk increases with both quantity and duration of smoking. Cigar and pipe smoking also increase risk. Exposure to radon gas, which is released from soil and can accumulate in indoor air, is thought to be the second-leading cause of lung cancer in the US. Other risk factors include exposure to secondhand smoke, asbestos (particularly among smokers), certain metals (chromium, cadmium, arsenic), some organic chemicals, radiation, air pollution, and diesel exhaust. Specific occupational exposures that increase risk include rubber manufacturing, paving, roofing, and painting.
SIGNS AND SYMPTOMS
Symptoms include persistent cough, sputum streaked with blood, chest pain, voice change, worsening shortness of breath, and recurrent pneumonia or bronchitis. Symptoms usually do not appear until the cancer is advanced.
Appropriate treatment for lung cancer is based on whether the tumor is small cell (13%) or non-small cell (84%), as well as the stage and molecular characteristics. For early-stage non-small cell lung cancer, surgery is the usual treatment, sometimes with chemotherapy, alone or in combination with radiation therapy. Advanced-stage non-small cell lung cancer is usually treated with chemotherapy, targeted drugs (or a combination of the two), or immunotherapy. Small cell lung cancer is usually treated with chemotherapy, alone or combined with radiation; a large percentage of patients on this regimen briefly experience remission, although the cancer often returns.
Screening with low-dose spiral computed tomography (LDCT) has been shown to reduce lung cancer mortality by about 20% compared to standard chest x-ray among current or former (quit within 15 years) heavy smokers. The American Cancer Society recommends annual screening for lung cancer with LDCT in adults 55 to 74 years of age who are current or former heavy smokers and in relatively good health who have received evidence-based smoking-cessation counseling (if they are current smokers) and have undergone a process of informed/shared decision making that included a description of the potential benefits, limitations, and harms associated with lung cancer LDCT screening. Screening should not be viewed as an alternative to smoking cessation.