The purpose of this report is to update a previous evidence review commissioned by the U.S. Preventive Services Task Force (USPSTF) on screening for lung cancer. In 2004, based on the previous evidence review, the USPSTF found there was insufficient evidence to either recommend for or against routinely screening asymptomatic persons for lung cancer with either low-dose computed tomography (LDCT), chest x-ray (CXR), sputum cytology, or a combination of these tests (I statement). Lung cancer is a proliferation of malignant cells arising in the airways or tissues of the lung. Ninety-five percent of lung malignancies are either non-small cell lung cancer (NSCLC) or small cell carcinoma, with small cell carcinoma accounting for 16 percent of cases. The remaining 5 percent of primary pulmonary malignancies include rare entities such as carcinoid tumor. NSCLC is a heterogeneous designation with subsets including squamous cell carcinoma, adenocarcinoma, large cell carcinoma, and undifferentiated carcinoma. Individual tumors can show features of several of these subtypes. Adenocarcinoma is the most common subtype, encompassing 36 percent of all lung cancers, with squamous cell carcinoma making up 20 percent of cases in a large survey of U.S. lung cancer from 1998 to 2001. The World Health Organization has recently revised the histology classifications for lung cancer, including several new preinvasive lesions within the adenocarcinoma classification. Lung cancer is the second most commonly occurring cancer in the United States among men and women and the leading cause of cancer-related death. The American Cancer Society (ACS) predicted there would be approximately 226,160 new cases and 160,340 lung cancer-related deaths in the United States in 2012. Notably, lung cancer is expected to account for almost 28 percent of all cancer-related deaths in 2012. Current estimates suggest that almost 7 percent of men and women born today will be diagnosed with lung cancer during their lifetime and almost 6 percent will die from it. Lung cancer and lung cancer-related deaths have been increasing in epidemic proportions throughout the world, with differences between countries largely explained by differences in smoking rates. Worldwide, it is estimated there were 1.6 million new cases and 1.4 million deaths from lung cancer in 2008. Rates of lung cancer vary by smoking status. As a measure of the burden of lung cancer in the population, lung cancer is the leading cause of years of life lost to cancer in the United States, with an estimate of 15 years of life lost on average per person dying of lung cancer. Investigators created an analytic framework with the key questions and the patient populations, interventions, and outcomes reviewed. The target population for lung cancer screening was asymptomatic men and women at average risk or current and former smokers at high risk. Key Questions: 1. How effective is screening for lung cancer in reducing mortality and morbidity? a. How effective is screening in persons at average risk? b. How effective is screening in persons at higher risk for lung cancer (e.g., current or former smokers)? c. Does effectiveness differ by subgroups (e.g., sex, age, race, presence of comorbid conditions, other lung cancer risk factors)? 2. What are the test characteristics (sensitivity, specificity, predictive value) of screening tests for lung cancer? a. How do these test characteristics vary by lung cancer risk? b. How are test characteristics different by subgroups (e.g., sex, age, race)? 3. What are the harms associated with lung cancer screening and are there ways to modify harms (e.g., unnecessary biopsy, radiation exposure, overdiagnosis, and psychosocial harms)? 4. How effective is surgical resection for the treatment of early (stage IA) NSCLC? 5. What are the harms associated with surgical resection of early (stage IA) NSCLC?