Abstract and Introduction
Over the past 10 years, there has been substantial progress in the study and implementation of lung cancer screening using low-dose computed tomography (LDCT). The National Lung Screening Trial, the recently reported NELSON (NEderlands-Leuvens Longkanker Screenings ONderzoek) trial, and other European trials provide strong evidence for the efficacy of LDCT to reduce lung cancer mortality. This has resulted in the United State's Preventative Task Force and numerous professional medical societies adopting lung cancer screening recommendations. Despite the general acceptance of the positive effect of screening, low adoption and implementation rates remain nationally. In this article, the authors discuss the evolution and current state of the evidence for LDCT screening for lung cancer. The authors will also review the associated risks, cost, and challenges of implementation of an LDCT screening program.
Lung cancer is the leading cause of death among men and women. The American Cancer Society estimates that greater than 234,000 new lung cancers are diagnosed each year with over 154,000 lung cancer-related deaths. In the United States, lung cancer kills more women than colorectal cancer and breast cancer combined and more men than colorectal, prostate, and pancreatic cancer combined. Smoking cessation initiatives have been the first line in the effort to reduce the burden of lung cancer. Although great progress has been made in reducing the number of smokers, 15% of people in the United States still smoke and there remains a large population of previous smokers at high risk for lung cancer.
Survival in patients diagnosed with nonsmall cell lung cancer (NSCLC) is strongly related to stage at diagnosis. Based on the American Joint Commission on Cancer (AJCC) 8th edition staging, the 5-year survival ranges from 90% for stage IA1 to 0% for stage IVB. Unfortunately, 70% of patients are currently diagnosed with locally advanced or metastatic disease. Consequently, despite relatively good outcomes for appropriately treated early stage patients, the overall survival rate for subjects with NSCLC is only 18%.
The criteria for effective population cancer screening are well defined. The cancer must have a high morbidity and mortality, significant prevalence in the screened population, identifiable risk factors allowing for targeted screening in high-risk individuals, a preclinical phase, and evidence that therapy is more effective in early-stage disease. Screening efforts for NSCLC have been studied for many decades. Trials using chest radiographs and sputum cytology were not effective in demonstrating a survival benefit, nor were the initial trials using computer tomography (CT). That all changed in 2011 with publication of the National Lung Screening Trial (NLST) and efforts have now shifted from proving a benefit to screening for NSCLC, to overcoming the obstacles of integrating low-dose computed tomography (LDCT) screening into routine care.
Semin Respir Crit Care Med. 2020;41(3):447-452. © 2020 Thieme Medical Publishers