The AAFP concludes that the evidence is insufficient to recommend for or against screening for lung cancer with low-dose computed tomography (LDCT) in persons at high risk for lung cancer based on age and smoking history. (2013)
(Grade: I recommendation)
Grade Definition: http://www.uspreventiveservicestaskforce.org/uspstf/grades.htm(www.uspreventiveservicestaskforce.org)
AAFP Clinical Considerations: The AAFP has reviewed the USPSTF’s recommendation on lung cancer screening(www.uspreventiveservicestaskforce.org) and had significant concern with basing such a far reaching and costly recommendation on a single study. The National Lung Screening Trial (NLST)1, whose favorable results were conducted in major medical centers with strict follow-up protocols for nodules, have not been replicated in a community setting. A shared-decision-making discussion between the clinician and patient should occur regarding the benefits and potential harms of screening for lung cancer. The long term harms of radiation exposure from necessary follow-up full dose CT scans are unknown. The USPSTF recommends annual CT screening even though the NLST trial was only 3 annual scans; further benefit expectations are based on modeling.
The number needed to screen to prevent one lung cancer death over 5 years and 3 screenings is 312. The number needed to screen to prevent one death by any cause is 208 over 5 years in the NLST trial. Forty percent of patients screened will have a positive result requiring follow-up, mostly CT scans, although some will require bronchoscopy or thoracotomy. The harms of these follow-up interventions in a setting with a less strict follow-up protocol in the community is not known.
In the words of the NLST authors: "The NLST was conducted at a variety of medical institutions, many of which are recognized for their expertise in radiology and the diagnosis and treatment of cancer." Much of the success of this trial is based on the low mortality associated with surgical resection of tumors, which may not be reproducible in all settings.
In the words of the NLST authors: “The cost-effectiveness of low-dose CT screening must also be considered in the context of competing interventions, particularly smoking cessation."
USPSTF Clinical Considerations: http://www.uspreventiveservicestaskforce.org/uspstf13/lungcan/lungcanfinalrs.htm#consider(www.uspreventiveservicestaskforce.org)
1. Aberle DR, Adams AM, Berg CD, Black WC, Clapp JD, Fagerstrom RM, Gareen IF, Gatsonis C, Marcus PM, Sicks JD. Reduced lung-cancer mortality with low-dose computed tomographic screening(www.ncbi.nlm.nih.gov). N Engl J Med. 2011 Aug 4; 365(5):395-409.