The role of CT screening for Lung Cancer in clinical practice. The evidence based practice guideline of the American College of Chest Physicians and the American Society for Clinical Oncology

Posted ahead of print on on May 20, 2012
Peter B. Bach, MD, MAPP; Joshua N. Mirkin, BA; Thomas K. Oliver, BA; Christopher G. Azzoli, MD; Donald A. Berry, PhD; Otis W. Brawley, MD; Tim Byers, MD, MPH; Graham A. Colditz, MD, DrPH; Michael K. Gould, MD, MS; James R. Jett, MD; Anita L. Sabichi, MD; Rebecca Smith-Bindman, MD; Douglas E. Wood, MD; Amir Qaseem, MD, PhD, MHA; Frank C. Detterbeck, MD

Lung cancer is the leading cause of cancer death in the United States. Most patients are diagnosed with advanced disease, resulting in a very low 5-year survival rate. Screening for lung cancer has the potential to identify the disease in the earlier stages of development and to reduce the risk of death due to lung cancer. 

The review was a collaborative initiative of the American Cancer Society (ACS), the American College of Chest Physicians (ACCP), ASCO, and the National Comprehensive Cancer Network (NCCN).The review forms the basis of clinical practice guidelines developed by the ACCP and ASCO, with input from the American Thoracic Society (ATS) which has also endorsed the guideline. 

A systematic review of the role of low-dose computed tomography (LDCT) lung cancer screening for individuals at high risk of developing the disease due to smoking was undertaken to present a comprehensive picture of the evidence regarding the benefits and risks associated with LDCT screening. Other potential methods of screening, such as chest radiograph, sputum cytology, sputum biomarkers, and exhaled breath, were not reviewed.

Of three randomized controlled trials reporting survival outcomes for LDCT, one large high-quality study of 53,454 participants, the National Lung Screening Trial (NLST), detected significantly less lung cancer mortality (median follow-up, 78 months; relative risk [RR] = 0.80%, 95% CI: 0.73 to 0.93; p = 0.004) and all-cause mortality (RR = 0.93%, 95% CI: 0.86-0.99, p = 0.02) with LDCT screening. The considerably smaller ongoing DANTE and DLST studies each compared 5 annual rounds of LDCT screening to usual care; after a median of 34 and 58 months of follow-up, no statistically significant difference in lung cancer mortality was observed in either study. On average, false-positive results requiring further imaging and subsequent invasive procedures associated with LDCT screening were approximately 20% and 1%, respectively. LDCT screening benefits individuals at a high risk of developing lung cancer, but there remains uncertainty about potential harms and the generalizability of results outside the context of well-conducted randomized trials. CT screening should be conducted in settings similar to that of the NLST, conducted by clinicians with expertise in lung cancer screening, diagnoses, and treatment, and only in individuals who are at high risk of developing lung cancer. Additional research is needed to define subgroups most likely to benefit or be harmed from screening.

Based on the literature review, ASCO makes two major recommendations related to LDCT screening for lung cancer.

  1. For smokers and former smokers ages 55 to 74 who have smoked for 30 pack-years or more and either continue to smoke or have quit within the past 15 years, ASCO suggests that annual screening with LDCT should be offered over both annual screening with chest radiograph or no screening, but only in settings that can deliver the comprehensive care provided to NLST participants.
  2. For individuals who have accumulated fewer than 30 pack-years of smoking, are either younger than 55 or older than 74, or who quit smoking more than 15 years ago, as well as for individuals with severe comorbidities that would preclude potentially curative treatment and/or limit life expectancy, ASCO suggests that CT screening should not be performed.

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