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Clinicians should recommend annual lung-cancer screening by means of low-dose computed tomography (CT) for high-risk patients if both provider and patient meet certain conditions, according to the American Cancer Society Lung Cancer Screening Guidelines.

The guidelines evolved from a systematic review of evidence related to low-dose CT lung-cancer screening undertaken by the American Cancer Society (ACS), the American College of Chest Physicians (ACCP), the American Society of Clinical Oncology (ASCO), and the National Comprehensive Cancer Network (NCCN). The analysis was launched following the November 2010 release of the initial findings from the National Cancer Institute’s National Lung Screening Trial (NLST). NLST established that lung-cancer mortality in specific high-risk groups can be reduced by annual screening with low-dose CT. Participants who underwent low-dose helical CT scans had a 20% lower risk of dying from lung cancer than did participants who underwent standard chest radiographs. 


However, cautioned the authors of the new document, low-dose CT will not detect all lung cancers, nor will the imaging technique detect all lung cancers early. Moreover, not all patients who have a lung cancer detected by low-dose CT will avoid death from the disease.


Nevertheless, authors Richard Wender, MD, chair and alumni professor of the Department of Family and Community Medicine at Thomas Jefferson University Medical College in Philadelphia, Pennsylvania, and colleagues concluded that although this initial guideline will likely be revised as new data become available, sufficient evidence currently exists to support screening when the criteria presented in the recommendations are met. 


Specifically, clinicians who advise patients to undergo annual low-dose CT lung-cancer screening should have access to high-volume, high-quality lung cancer screening and treatment centers. Ideally, persons who choose to be tested should enter an organized screening program at an institution with expertise in low-dose CT screening, with access to a multidisciplinary team skilled in the evaluation, diagnosis, and treatment of abnormal lung lesions. If such a program is not available, the patient should be referred to a center that performs a reasonably high volume of lung CT scans, diagnostic tests, and lung cancer surgeries. Outside of such settings, screening risks may be substantially higher than those observed in the NLST, and screening is not recommended.


Patients can be considered candidates for annual low-dose CT lung-cancer screening if they are age 55 to 74 years; have a smoking history of at least 30 pack-years (pack-years are calculated by multiplying the number of packs of cigarettes smoked per day by the number of years a person has smoked); are current smokers or have quit smoking within the past 15 years; and have had a thorough discussion with a health care provider regarding the potential benefits, limitations, and harms associated with low-dose CT lung-cancer screening. 


Due to the degree of uncertainty regarding the balance of benefits and harms of screening for persons who fall outside of the set criteria, clinicians are advised not to not discuss low-dose CT lung-cancer screening with such patients. Eligible adults who do choose to be screened should follow the NLST protocol of annual low-dose CT screening until they reach age 74 years. Chest radiography should not be used for screening, nor should screening be viewed as an alternative to smoking cessation. As the guideline authors pointed out, smoking-cessation counseling remains a high priority for clinical attention in discussions with current smokers, who should be informed of their continuing risk of lung cancer. ONA