Lung cancer is the most deadly form of cancer in the United States.1 In 2013, approximately 228,190 new cases of lung cancer were diagnosed, and 159,480 deaths occurred as a result of this disease.1 Lung cancer kills more people each year than breast, prostate, colorectal and pancreatic cancer combined. Research has shown that 5-year survival rates are greatly improved when the disease is caught while still localized; unfortunately, only 15% of lung cancers are diagnosed at this early stage.1
Past studies directed at screening for lung cancer in asymptomatic patients did not demonstrate improved survival.2 Screening methods examined in this research included chest x-ray, sputum cytology and computed tomography (CT). Although these measures detected cancers, the number of deaths did not decrease significantly as a result of identification.3 Researchers have continued to seek an effective lung cancer screening tool that might decrease mortality in the way that other commonly accepted screening practices have done for their respective diseases.
The National Lung Cancer Screening Trial (NLST) began in 2002 as a multisite randomized, controlled trial at 33 U.S. medical centers. More than 53,000 participants enrolled in this study. All participants were deemed at high risk for lung cancer: They were between the ages of 55 and 74, with at least a 30 pack-year history of smoking. To qualify for enrollment, former smokers must have quit less than 15 years prior to the study.4
Participants received yearly screening for lung cancer for 3 years: one group with posteroanterior chest x-ray and the other with low-dose helical CT (LDCT) scans. Data were collected on these patients until the end of 2009. The study sought to determine if the use of LDCT would reduce lung cancer mortality. The study documented a 20% reduction in lung cancer mortality in the LDCT group as compared to the x-ray group.4 Although this was a promising result, the researchers acknowledged that the findings were not sufficient to support national guidelines for LDCT screening.4
Within the CT arm of the NLST, 1,060 lung cancers were diagnosed. Of these, 649 were diagnosed after a positive screening, 44 after a negative screen, and 367 after missing a screen or in the interim after the screening phase was complete. In the radiography group, 941 lung cancers were diagnosed. Of these, 279 diagnoses were made after a positive screen and 137 were made after a negative screen. An additional 525 were diagnosed in the radiography group after missing a screening or during the surveillance period of the study.4
Across the three screening exams, 39.1% of the patients who underwent LDCT and 16% of the radiography group received at least one positive screening result. The false positives were 96.4% and 94.5%, respectively. While the NLST gathered information about the workup that resulted from positive screenings, the workup was decided upon and performed by each patient's own healthcare team, not according to any one protocol. The NLST reported that most positive screens were followed with further imaging, and few resulted in invasive diagnostic procedures.
Considerations in Screening
The challenge with any screening tool is finding a balance between false-negative and false-positive results. False-negative results cause false security in the patient and delay diagnosis of disease that is actually present. False-positive results cause increased anxiety for the patient, as well as increased healthcare costs and exposure to potential risks with further diagnostic procedures. An inverse relationship often exists between false negatives and false positives; a tool sensitive enough to reduce false negatives will increase false positive results.4,5
Many questions surround the concept of LDCT screening for lung cancer. Who should be screened, how frequently, how much will it cost, and how will repeated exposure to LDCT radiation affect patients? After the NLST was published, many prominent agencies began to evaluate and update their recommendations about lung cancer screening.
Late in 2013, the U.S. Preventive Services Task Force (USPSTF) published a recommendation statement supporting yearly screening with LDCT for patients who meet age and history criteria (see table). The USPTF also stated that people unwilling for not healthy enough to undergo curative lung surgery likely would not benefit from screening. Screening should be viewed as an adjunct to tobacco cessation programs, the USPTF said.6
The American Cancer Society (ACS) published a guidelines in 2013, stating that patients who meet NLST criteria may be screened after a discussion of the risks, benefits and limitations of screening. If screening is chosen, providers should recommend yearly screening at a facility with a formalized screening program. The ACS also emphasizes that smoking cessation should remain a high priority, and that screening should not be used as an alternative to risk reduction.7
The National Cancer Institute has published a summary of available evidence, but no recommendations.8 The American Lung Association (ALA) has released an interim statement to help guide patients and providers about lung cancer screening. It recommends LDCT screening for patients who meet NLST criteria as well as the development of education materials for patients and ethical policies for providers.2
The National Comprehensive Cancer Network (NCCN) has issued a guideline in support of LDCT screening for lung cancer. The guideline recommends screening of patients at high risk, as set forth in the criteria for the NLST. In addition, NCCN also endorses screening for people 50 and older with at least a 20 pack-year history, along with one other risk factor. Risk factors include radon exposure, occupational exposure, prior cancer, chronic obstructive pulmonary disease, pulmonary fibrosis and family history of lung cancer. The NCCN guidelines also set forth specific instructions for evaluation and follow-up of abnormalities found on LDCT.9
Direct-to-consumer information may result in patients requesting LDCT for screening purposes. The healthcare provider must be familiar with the benefits and risks of LDCT screening, including anxiety and the effects of false positives: additional work-up, costs and cumulative exposure to radiation. Patients must be educated about the risks and benefits before undergoing screening. The decision to screen must be based on the highest level of available evidence, the expertise of the provider, and the beliefs of the patient. While the LDCT group in the NLST demonstrated a 20% reduction in lung cancer deaths, 356 of the 1,060 patients diagnosed with lung cancer in this group ultimately died from it.4 The take-home point for patients is that screening does not guarantee detection or successful treatment, and it should not replace efforts to reduce risks in the first place.
Risk reduction efforts aimed at smoking prevention and cessation continue to be essential. The availability of lung cancer screening may give false reassurance to smokers and lead to decreased attempts to quit. When discussing these matters with patients, the provider must emphasize the multiple disease states linked to smoking. The patient must understand that smoking leads to multiple cancers outside the lung, including oral, laryngeal, esophageal, gastric, pancreatic, cervical, renal and bladder cancers.10
Currently, Medicare and many insurance payers do not cover the costs of LDCT for lung cancer screening.11 In late 2011, Wellpoint, the parent company of Blue Cross Blue Shield, announced the decision to cover CT screening for lung cancer. Three yearly screens are covered for recipients who meet the NLST criteria. Wellpoint is the insurance provider for 34 million Americans.12
CT for diagnostic purposes is covered by Medicare, but it may be subject to co-pay and deductible.13 A diagnostic study is eligible for coverage when the patient is already displaying symptoms of lung cancer, such as cough, chest pain or weight loss.
One option that may be beneficial to the patient who requests lung cancer screening would be to refer to current cancer screening trials. The National Institutes of Health maintain a registry of clinical trials at www.clinicaltrials.gov. The costs of screening may be covered by a trial, the patient will be educated about the benefits and risks in a controlled environment, and the results can be analyzed and used in the future to benefit other patients.
Angela Mays is a nurse practitioner who specializes in hematology and oncology at Cancer Specialists of North Florida in Jacksonville. She has completed a disclosure statement and reports no relationships related to this article.
1. American Cancer Society. Cancer facts and figures 2013. http://www.cancer.org/acs/groups/content/@epidemiologysurveilance/documents/document/acspc-036845.pdf
2. American Lung Association. Providing guidance on lung cancer screening to patients and physicians. http://lung.org/lung-disease/lung-cancer/lung-cancer-screening-guidelines/lung-cancer-screening.pdf
3. Walsh J. Low dose spiral computerized tomography screening for lung cancer. California Technology Assessment Forum. http://www.ctaf.org/assessments/low-dose-spiral-computerized-tomography-ldsct-screening-lung-cancer
4. Reduced lung-cancer mortality with low-dose computed tomographic screening. N Engl J Med. 2011;365(5):395-409.
5. Kemp C, Potyk D. Cancer screening: principles and controversies. Nurs Pract. 2005;30(8): 46-50.
6. Moyer VA. Screening for Lung Cancer: U.S. Preventive Services Task Force Recommendation Statement. http://www.uspreventiveservicestaskforce.org/uspstf/uspslung.htm
7. Wender R, et al. American Cancer Society lung cancer screening guidelines. CA Cancer J Clin. 2013;63:106-117.
8. National Cancer Institute. Lung cancer screening. Bethesda, MD: National Cancer Institute. Lung Cancer Screening. http://cancer.gov/cancertopics/pdq/screening/lung/HealthProfessional
9. National Comprehensive Cancer Network. Lung cancer screening version 1.2013. http://www.nccn.org/professionals/physician_gls/pdf/lung_screening.pdf
10. Centers for Disease Control and Prevention. Health effects of cigarette smoking. http://www.cdc.gov/tobacco/data_statistics/fact_sheets/health_effects/effects_cig_smoking/
11. Centers for Medicare and Medicaid Services. Your guide to Medicare's preventive services. www.medicare.gov/Publications/Pubs/pdf/10110.pdf
12. Mathews AW. Wellpoint to cover lung CT for heavy smokers. The Wall Street Journal. December 1, 2011. http://blogs.wsj.com/health/2011/12/01/wellpoint-to-cover-lung-ct-scans-for-heavy-smokers/
13. US Department of Health and Human Services. Find out if Medicare covers your test, item or service. http://www.medicare.gov/Coverage/Home.asp