New guidelines (http://www.nccn.org/professionals/physician_gls/pdf/lung_screening.pdf) from the National Comprehensive Cancer Network (NCCN; http://www.nccn.org) have recently been released on the use of computed tomography (CT) scans for lung cancer screening. These guidelines result primarily from data generated by the National Lung Screening Trial (NLST) and provide a new avenue for combating lung cancer.

To help you better understand the guidelines and the main clinical trial they are based upon, we have provided some answers to frequently asked questions:

What is spiral CT?
Spiral CT (also called “helical” CT) is a type of X-ray that makes 3-D images by rotating the scanner around the body.

What is the NLST?
The National Lung Screening Trial (NLST) was a large, national study that compared low-dose spiral CT and standard chest X-ray to screen for lung cancer to see if they reduced deaths by finding tumors at an early, more treatable stage. The trial, which began in 2002, was sponsored by the National Cancer Institute (NCI; http://www.cancer.gov). 

The trial found there were 20 percent fewer lung cancer deaths in the people who got CT scans compared to those who had chest X-rays. This result was published in July, 2011, and is the main basis for the screening guidelines described below.

What do the guidelines say?
The National Comprehensive Cancer Network guidelines (http://www.nccn.org/professionals/physician_gls/pdf/lung_screening.pdf) recommend base-line CT screening for the following “high-risk” groups:

• people 55-74 with a history of heavy smoking - at least “30- pack years”, which would include people who smoked one pack of cigarettes per day for 30 years or people who smoked two packs per day for 15 years, or three packs per day for 10 years, etc. 
• people over age 50 with a history of moderately high smoking – at least 20 pack-years - PLUS one other risk factor.

In addition to smoking, what are the other risk factors for lung cancer considered in the screening guidelines?
The NCCN defines additional risk factors as:

• Documented radon exposure
• Occupational exposure to specific chemical agents
• History of other cancers (particularly if radiation to the chest was included in prior treatment)
• Family history of lung cancer
• COPD or pulmonary fibrosis

Should people with a light smoking history get a CT scan?
The NCCN does not recommend lung cancer screening for anyone other than the groups described above.

If I fit the profile of someone considered at “high-risk” for lung cancer, where should I go to get screened?
For people who do decide to seek out CT screening, it is important to go to a health care center experienced in providing lung cancer screening, and able to evaluate and follow any findings from the screen. Experienced sites include:

• National Cancer Institute (NCI)-Designated Cancer Centers
• National Comprehensive Cancer Network Institutions
• National Lung Screening Trial (NLST) sites
• International Early Lung Cancer Action program (I-ELCAP) sites

What does spiral CT cost and is it covered by insurance?
The cost of a spiral CT varies but is usually in the range of $300 to $500. Because the guidelines are so new, some insurers and Medicare may not currently pay for CT scans to screen for lung cancer. CT scans for people who already have symptoms of lung cancer – called “diagnostic” CTs – are covered by most insurers.

Are there any risks to having a CT scan?
CT scans pose some risk from radiation exposure. The amount of exposure in a low-dose spiral CT is about the same as in a mammogram. Also, there is the risk of “false positives,” when the CT finds something abnormal that turns out not to be cancer. These findings must be followed up with more CT scans and sometimes with a lung biopsy or chest surgery, which can pose additional risks. In the NLST study, abnormalities were found in about 25 percent of people screened with CT. The majority of these did not turn out to be cancer.

If my first CT scan is negative, how often should I be screened?
The NCCN recommends annual screening for at least 3 years. You and your doctors will decide together how best to proceed with your care after that time.

If my initial screen is negative or I have regular CT scans, is it safe to continue smoking? Absolutely not. Smoking is as dangerous as ever. Lung cancer causes more deaths than breast, colon, and prostate cancer combined. And 85 percent of people with lung cancer currently smoke or used to smoke. This year alone, it is expected that nearly 157,000 people will die of lung cancer in the United States. While CT reduced the death rate from lung cancer in people with a heavy smoking history in the NLST, it did not prevent all deaths. If you are still smoking, please visit one of our partners to learn how you can quit.

How does screening for lung cancer with CT compare to other health screenings, such as mammography?
CT appears to be very effective. In the NLST, screening 300 people with CT scans for three years resulted in extending one life. In mammography, for example, 465 women must be screened for seven years to extend one life.

Where can I learn more about lung cancer?
The National Lung Cancer Partnership has comprehensive facts about lung cancer, and information for lung cancer patients and their loved ones.  If the information you seek is not available on our website, please contact us.