Why Should I Screen Patients?

Rationale For Screening

Lung cancer is the leading cause of cancer death among men and women. The majority of patients present with symptoms, at which time lung cancer is advanced and not curable.

Lung cancer is a source of morbidity and mortality for many patients due to the prevalence of tobacco use. Unfortunately, the majority of patients diagnosed with non-small cell lung cancer (NSCLC) will ultimately succumb to cancer-related death, as most patients present with locally advanced or metastatic stage disease [1]. In an effort to avoid the poor outcomes traditionally associated with NSCLC, research methodology introduced goals aimed at the prevention of advanced disease states, focusing on tools for early detection and screening in an effort to improve outcomes.

Smoking Cessation remains the mainstay of primary prevention of lung cancer

Smoking cessation and avoidance of secondary tobacco exposure is an effective means of prevention, as most lung cancer occurs in prior smokers [2]. Increasingly, clinical trials have focused on evidence-based data for screening, particularly in high-risk populations.

Prior efforts at early detection by chest x-ray failed to improve survival.

The Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening trial [3, 4] failed to demonstrate a benefit associated with the use of chest radiography (CXR) in screening for lung cancer.  The six year follow up analysis showed no difference in survival rates between the screened and observed groups [3].  Other clinical trials [6, 7, 8] also noted that CXR screening resulted in no statistically significant reduction in lung cancer mortality.

Recent large scale randomized prospective trials of low dose CT scan have proven a 20% reduction in mortality.

However, data from the National Lung Screening Trial (NLST) now provides evidence that screening with low-dose CT scan (LDCT) of the chest can have a significant impact in reduction of cancer-associated deaths from NSCLC [9]. The randomized clinical trial enrolled over 53,000 high risk patients of ages 55-74 for annual screening by LDCT imaging compared to CXR annually for a total of three years. The patient population included both genders with a social history of at least 30 pack-years of tobacco use. The trial included current smokers, and it also enrolled prior smokers with cessation within 15 years prior to clinical trial enrollment. The NLST was stopped in 2010, after interim analysis detected a benefit in favor of LDCT [5]. Follow-up at 6 years confirmed the initial findings: LDCT imaging decreased disease specific mortality from lung cancer by 20%, and decreased all cause mortality by 6.7%. [5]

CMS as well as NCCN , ACCP, ACS, ASCO and many other groups have endorsed Low Dose Screening CT as effective in mortality reduction in patients at risk.

Subsequent to NLST, the American College of Chest Physicians (ACCP), American Cancer Society (ACS), National Comprehensive Cancer Network (NCCN), and American Society of Clinical Oncology (ASCO) conducted a systematic review of the available data to form screening guidelines [9]. Following review of data, NCCN issued criteria for high risk groups in favor of screening with LDCT for this population. Screening criteria include ages 55-74 with a 30 pack-year history of smoking, current smoking, or prior cessation within 15 years, or a 20 pack-year history of smoking with one additional risk factor [10]. ACCP [9] and ASCO also incorporated these findings into guidelines [12]. The US Preventive Services Task Force now recommends annual LDCT scans for patients who are 55 to 80 years old, along with discontinuation of screening in individuals who have not used tobacco in greater than 15 years [13]. ACS has issued guidelines in with respect to LDCT screening as well [14]. All guidelines emphasize discussion of risks and benefits of screening, with need for a multidisciplinary approach to manage testing in the event of a positive screen.

NLST has provided strong evidence in favor of LDCT screening for reduction of disease-specific mortality from NSCLC. Expert panels reviewed the available data and developed consensus guidelines and recommendations favoring LDCT screens, thus becoming the new standard of care for NSCLC early detection in high risk populations.


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  2. Fontham ET, et al. Environmental tobacco smoke and lung cancer in nonsmoking women. A multicenter study. JAMA 1994; 271:1752.

  3. Prorok PC, et al. Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial. Control Clin Trials 2000; 21:273S.

  4. Oken MM, et al. Screening by CXR and lung cancer mortality: the PLCO randomized trial. JNatl Cancer Inst 2005; 97:1832.

  5. Aberle DR, et al. Reduced lung-cancer mortality with low-dose computed tomographic screening. N Engl J Med 2011; 365:395.

  6. Bach PB, et al. Is our natural history model of lung cancer wrong? Lancel Oncol 2008; 9:693.

  7. Ebeling K, et al. Screening for lung cancer—results from a case-control study. Int J Cancer 1987:40:141.

  8. Marcus PM, et al. Extended lung cancer incidence follow-up in the Mayo Lung Project and overdiagnosis. J Natl Cancer Inst. 2006: 98(11):748.

  9. Bach PB, et al. Benefits and harms of CT screening for lung cancer: a systematic review. JAMA 2012: 307:2418.

  10. NCCN Guidelines. http://www.nccn.org.

  11. Bach PB, et al. Computed tomography screening and lung cancer outcomes. JAMA 2007; 297:953.

  12. Detterbeck FC, et al. Screening for lung cancer: Diagnosis and management of lung cancer, 3rd ed: American College of Chest Physicians evidence-based clinical practice guidelines. Chest 2013; 143:e78s.

  13. U.S. Preventive Task Force Recommendation Statement: Screening for Lung Cancer.

  14. Wender R, et al. American Cancer Society lung cancer screening guidelines. CA Cancer J Clin 2013; 63:107.