Computed tomography (CT) is a radiographic imaging technique that can provide high quality three-dimensional images of the lungs during a single breath hold. Due to its speed and sensitivity in detecting small lung lesions, low-dose spiral CT scanning (also known as helical CT), a variation of standard CT imaging, has been proposed as a screening test for lung cancer in high-risk individuals (e.g., smokers). Standard CT, multidetector CT, low-dose CT, and electron beam CT devices are also addressed by this document.

Note: This document does not address CT scans performed for evaluation of chest related symptoms or follow-up evaluation of abnormalities previously detected when a CT scan of the chest was performed for a medically necessary reason.

Note: Please see the following documents for additional information:

• RAD.00037 Whole Body CT Scanning

Medically Necessary:

The use of low-dose spiral (helical) multi-detector CT imaging as a screening technique for lung cancer is considered medically necessary when used to screen for lung cancer for certain high-risk individuals when ALL of the following criteria are met:

1. Individual has no signs or symptoms suggestive of underlying lung cancer which includes, but is not limited to the following: unexplained cough, hemoptysis, or unexplained weight loss of more than 15 pounds in the past year; AND
2. Individual is between 55-74 years of age; AND
3. There is at least a 30 pack-year history of cigarette smoking; AND
4. If the individual is a former smoker, that individual had quit smoking within the previous 15 years; AND
5. Individual has CT scans performed once a year for 3 consecutive years.

Investigational and Not Medically Necessary:

The use of CT scanning as a screening technique for lung cancer in asymptomatic individuals is considered investigational and not medically necessary when the above criteria are not met and for all other indications.

The basic premise of oncology screening tests is to detect cancer at an earlier stage, when treatment is hopefully more effective. Although screening may indeed identify cancer at an earlier stage, an associated improved survival will only result if effective surgical or medical treatment is available. The sensitivity of such a test must be balanced against its specificity, since lack of specificity will result in an increasing number of individuals undergoing unnecessary work-ups due to false positive results. Several published studies from Japan and the United States compared the cancer detection rate of spiral CT with that of standard chest x-ray in asymptomatic high-risk individuals (e.g., smokers) (Diederich, 2002; Gohagan, 2005; Kakinuma, 1999; Nawa, 2002; Sobue, 2002). While the CT scanning improved the detection rate of suspicious lesions, the false positive rates were much higher with helical CT than with chest x-ray.

The efficacy of spiral CT scanning for lung cancer screening continues to be a topic of debate, with additional studies supporting the fact that a spiral CT scan is more sensitive than the chest x-ray in identifying lung lesions (Gohagan, 2005; Sobue 2002; Sone 2001).

The heterogeneous nature of lung cancer may limit the benefit of screening. For example, some lung cancers may be very aggressive such that close surveillance and early detection will not affect outcome. Some small cancers may also present with metastatic disease; in other words, the size of the cancer may not necessarily correlate with early stage disease. At the other end of the spectrum, some cancers detected with screening may be indolent and not clinically relevant.

There is concern that, should CT screening for lung cancer become widespread, a major increase in unnecessary, procedures and complications could result. Annual CT screening raises another concern regarding unnecessary radiation exposure risk (even that deemed as "low-dose"), which some have calculated that if performed over a period of many years, may in itself contribute to an increased cancer risk (Brenner, 2004).

In September 2002, the National Cancer Institute launched a randomized study of 50,000 current or former smokers to be randomized to screening on three consecutive years with either a chest x-ray or spiral CT. The principal outcome of this 8-year study is lung cancer mortality and to determine the potential benefits and drawbacks of the two screening methods. In 2011 the National Lung Screening Trial Research Team released their findings of the National Cancer Institute study. Enrollment occurred from August 2002 through April 2004. The screening took place from August 2002 through September 2007. Follow-up continued through December 2009. High-risk individuals were randomized to undergo either yearly CT scans or yearly chest x-rays for 3 years. Participants included in the study were considered to be at high-risk if they were between the ages of 55-74, had at least a 30 pack-year history of smoking and if participants were former smokers, they had quit within the previous 15 years. Participants were excluded from the study if they had a previous diagnosis of lung cancer, if they had a chest CT in the preceding 18 months, had hemoptysis, or had an unexplained weight loss of at least 15 pounds within the preceding year. A total of 26,722 participants were randomly assigned to have low-dose CT and 26,732 received chest x-ray. For those individuals who received a diagnosis of lung cancer after the first test, subsequent screening tests were not offered. Comparative interpretations were used to determine the outcome of the screening tests. A positive result was considered for CT scan if there was any non-calcified nodule measuring at least 4mm in diameter. A result was considered positive for chest x-ray if there was any non-calcified nodule or mass. Other abnormalities such as adenopathy or effusion could also be classified as a positive result. If after the third round of screening, abnormalities suspicious for lung cancer were stable during all three rounds, they could then be classified as a minor abnormality as opposed to a positive result.

As previously stated, participants were followed through December 2009. Participants completed questionnaires regarding vital status. Those who did not complete questionnaires (i.e., those who were lost to follow-up) were checked for in the National Death Index for information about their vital status. For those individuals known to have died, death certificates were checked for cause of death. Adherence rates in the screening were 95% in the low-dose CT group and 93% in the chest x-ray group.

With all 3 rounds of screening, there were a higher number of positive results with the low-dose CT group as opposed to the chest x-ray group. In the low-dose CT group positive results were 27.3% after the first screen, 27.9% after the second screen and 16.8% after the third screen. For the chest x-ray group positive results were 9.2% after the first screen, 6.2% after the second screen and 5.0% after the third screen. After the first round of screening, more than 90% of the positive tests resulted in further diagnostic evaluation and further imaging tests. Following the three rounds of screening, 96.4% of the positive results in the low-dose CT group and 94.5% of the positive results in the chest x-ray group were determined to be false positive results. A total of 1,060 lung cancers were diagnosed in the low-dose CT group and 941 were diagnosed in the chest x-ray group. There were 356 deaths from lung cancer in the low-dose CT group and 443 deaths from lung cancer in the chest x-ray group which resulted in a relative reduction in the rate of death from lung cancer with low-dose CT screening of 20%. Overall there were 1,877 deaths in the low-dose CT group and 2,000 deaths in the chest x-ray group.

An independent board met every six months to review the accumulating data. In October of 2010 the independent board determined that a definitive result had been reached and recommended that the results be reported. There were some limitations to this study. There was a high rate of false positive results in the low-dose CT group. There is potential for bias affected by the "healthy-volunteer" effect. The scanners used during the trial are not as technologically advanced as the scanners are currently. The trial was conducted at a variety of medical institutions, some known for their radiological expertise which community facilities may not have. Overdiagnosis is a source of controversy surrounding low-dose CT screening for lung cancer and radiation-induced cancers could not be measured directly in this study. Smaller, randomized trials are underway in Europe and may need meta-analyses due to the smaller numbers. The investigators of the National Lung Screening Trial are analyzing data about costs, cost-effectiveness and quality of life effects. With a 20% reduction in mortality from lung cancer with low-dose CT screening, this trial can help select individuals who are best suited for low-dose CT screening.

Computed tomography (CT) scanning is a radiographic technique that can provide high quality three-dimensional images. Due to its sensitivity in detecting small lung lesions, spiral CT scanning, also know as helical CT scanning, has been proposed as a screening test for lung cancer in high-risk individuals (e.g., smokers). Other types of CT devices, including standard CT, electron beam CT and multidetector CT, have also been proposed for lung cancer screening. Some devices have been reported to provide lower radiation exposure during scanning. Such low-dose devices include spiral CT and multidetector CT devices.

In addition to the specific CT devices previously mentioned, computer image analysis software systems have been developed that assist the radiologist in the interpretation of CT scans. Several such systems have received approval from the Food and Drug Administration (FDA), however at this time it is unclear if such systems aid in lung cancer screening programs.

Asymptomatic: Without obvious signs or symptoms of disease.

Hemoptysis: Coughing up blood.

Lung cancer: A cancerous growth in lung tissue.

Pack-year: A way to measure the amount an individual has smoked over a long period of time.

The following codes for treatments and procedures applicable to this document are included below for informational purposes.  Inclusion or exclusion of a procedure, diagnosis or device code(s) does not constitute or imply member coverage or provider reimbursement policy.  Please refer to the member's contract benefits in effect at the time of service to determine coverage or non-coverage of these services as it applies to an individual member.

When services may be Medically Necessary when criteria are met: 

When services are Investigational and Not Medically Necessary
For the procedure and diagnosis codes listed above when criteria are not met, or when the code describes a procedure indicated in the Position Statement section as investigational and not medically necessary.

Future ICD-10 coding (effective 10/01/2013)
A draft of ICD-10 Coding related to this document, as it might look today, is available for reference and comments at: Appendix 1: Future ICD-10 coding

Peer Reviewed Publications:

1. Brenner DJ. Radiation risks potentially associated with low-dose CT screening of adult smokers for lung cancer. Radiology. 2004; 231(2):440-445.
2. Diederich S, Wormanns D, Semik M, et al. Screening for early lung cancer with low dose spiral CT: Prevalence in 817 asymptomatic smokers. Radiology. 2002; 222:773-781.
3. Gohagan JK, Marcus PM, Fagerstrom RM, et al. The Lung Screening Study Research Group. Final results of the Lung Screening Study, a randomized feasibility study of spiral CT versus chest X-ray screening for lung cancer. Lung Cancer. 2005; 47(1):9-15.
4. Jett JR. Spiral computed tomography screening for lung cancer is ready for prime time. Am J Respir Crit Care Med 2001; 163(4):812-815.
5. Kakinuma R, Ohmatsu H, Kaneko M, et al. Detection failures in spiral CT screening for lung cancer: Analysis of CT findings. Radiology. 1999; 212(1):61-66.
6. Markowitz SB, Miller A, Miller J, et al. Ability of low-dose helical CT to distinguish between benign and malignant noncalcified lung nodules. Chest. 2007; 131(4):1028-1034.
7. National Lung Screening Trial Research Team, Aberle DR, Adams AM, et al. Reduced lung-cancer mortality with low-dose computed tomographic screening. N Engl J Med. 2011; 365(5):395-409.
8. Nawa T, Nakagawa T, Kusano S, et al. Lung cancer screening using low-dose spiral CT. Chest 2002; 122(1):15-20.
9. New York Early Lung Cancer Action Project Investigators. CT Screening for lung cancer: diagnoses resulting from the New York Early Lung Cancer Action Project. Radiology. 2007; 243(1):239-249.
10. Patz EF, Goodman PC. Low dose spiral computed tomography screening for lung cancer. Not ready for prime time. Am J Respir Crit Care Med. 2001; 163(4):813-815.
11. Patz EF, Goodman PC, Bepler G. Screening for lung cancer. N Engl J Med. 2000; 343(22):1627-1633.
12. Sobue T, Moriyam N, Kaneko M, et al. Screening for lung cancer with low-dose helical computed tomography: Anti-Lung Cancer Association Project. J Clin Oncol. 2002; 20(4):911-920.
13. Sone S, Li F, Yang ZG, et al. Results of three-year mass screening programme for lung cancer using mobile low-dose spiral computed tomography scanner. Br J Cancer. 2001; 84(1):25-32.

Government Agency, Medical Society, and Other Authoritative Publications:

1. Centers for Medicare and Medicaid Services. National Coverage Determination: Computerized Tomography. NCD #220.1. Effective March 12, 2008. http://www.cms.hhs.gov/mcd/index_list.asp?list_type=ncd. Accessed on August 16, 2011.
2. Manser RL, Irving LB, Stone C, et al. Screening for lung cancer. Cochrane Database Syst Rev. 2004; (1):CD001991.
3. NCCN Clinical Practice Guidelines in Oncology™. © 2012 National Comprehensive Cancer Network, Inc. Non-small cell lung cancer. For additional information visit the NCCN website: http://www.nccn.org/index.asp. Accessed on October 13, 2011.
4. U.S. Preventive Services Task Force. Lung cancer screening: recommendation statement. Ann Intern Med. 2004; 140(9):738-739.

1. National Cancer Institute. Lung Cancer. Available at: http://www.cancer.gov/cancertopics/types/lung. Accessed on August 15, 2011.
2. National Lung Cancer Screening Trial. Available at: http://www.cancer.gov/nlst. Accessed on August 15, 2011.

CT Scans for Lung Cancer Screening
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Lung CT
MDCT
Multidetector CT
Multiple Row Detector CT
Syngo^® Lung CAD

The use of specific product names is illustrative only.  It is not intended to be a recommendation of one product over another, and is not intended to represent a complete listing of all products available.