Lung Screening FAQ

Lung cancer is detected using a screening test called a low-dose CT scan (LDCT). LDCT is CT scan that has the potential to detect lung cancer at earlier stages.

You are eligible for lung screening if you meet specific criteria, including age and smoking status.

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Lung cancer may be cured if it is discovered early before it causes symptoms. Unfortunately, once a person develops symptoms, lung cancer may advance to a stage that prevents cure.

A study funded by the National Cancer Institute, the National Lung Screening Trial (NLST), found that low-dose CT (LDCT) screening resulted in 20% fewer lung cancer deaths compared to screening with a standard chest X-ray. More of the lung cancers detected by LDCT were at an earlier stage than those detected by chest X-ray.

You will only benefit fully if you continue with annual screening until age 77 or until you have quit smoking for 15 years. If you are a current smoker, the best way to prevent lung cancer is to stop smoking and get screened annually. For free help to stop smoking, please call the Massachusetts Smokers’ Helpline at 800-QUIT-NOW (800-784-8669) or visit www.smokefree.gov.

The risks of low-dose CT scans (LDCT) can be divided into false positive or negative findings, over diagnosis, incidental findings, radiation exposure and anxiety.

• False Positive Findings - While LDCT screening for lung cancer can save lives, it has a high number of false positives, findings that appear abnormal but turn out to be non-cancerous. An example is a nodule caused by a scar or old infection. Up to one quarter of patients screened will have a finding in the lungs that requires further testing, but the majority of these findings do not represent cancer. You may need further tests, most commonly a repeat CT scan. Your doctor may refer you to specialists at a multidisciplinary nodule clinic or request a PET scan, lung biopsy or surgery.
• Over Diagnosis - Screening can discover small lung cancers that may not cause you any harm in your lifetime but can result in further testing or surgery.
• False Negative Findings - Screening may not pick up some cases of lung cancer. In the National Lung Screening Trial (NLST), about 4% of lung cancers were not detected at screening.
• Incidental Findings - Other findings may be discovered in organs that are also imaged during LDCT, such as the heart, abdomen, blood vessels and thyroid gland. You may already be aware of some, and some might be new findings. These findings may require further testing.
• Radiation Risk - As with all CT exams, LDCT screening for lung cancer exposes you to radiation. The dose is equal to about a quarter of the naturally occurring background radiation received at sea level per year. This dose is about one quarter of a standard chest CT and about the same as a mammogram. It is difficult to document the exact amount of increased risk from radiation, but studies suggest that radiation slightly increases your incidence of cancer. Our team has extensive experience using the latest technology to detect lung cancer, and we are committed to minimizing radiation exposure for all exams.
• Anxiety - Having an LDCT, waiting for the results and further evaluation for positive or incidental findings may cause stress and anxiety in some patients. Your doctor can discuss these risks with you and answer any questions that you may have.

Low-dose CT (LDCT) screening requires a referral from your doctor. Talk to your doctor about your risk for lung cancer and if you are eligible to be screened. Your healthcare provider can explain the risks and benefits, explain the results and arrange any next steps.

You don't need to do anything to prepare for a low-dose CT scan (LDCT) to screen for lung cancer. You do not need to fast or take oral contrast. You can continue taking all your medications and eat and drink normally. We suggest you leave your valuables at home because jewelry from the neck to the upper abdomen can affect the image quality.

You lie on your back on the CT scan table with your hands above your head. The table will move in and out of a donut-shaped ring where X-rays are generated and detected. You will be asked to hold your breath for a few seconds. You will not need IV contrast (dye). The procedure takes approximately two minutes, and you may leave once it is completed. You do not wait for the results.

A thoracic radiologist will report your low-dose CT scan (LDCT), using any prior scans you have had for comparison. The results will be sent to your doctor who may contact you and make recommendations for next steps if needed. The results will be available in Mass General Brigham Patient Gateway. 

Low-dose CT (LDCT) to screen for lung cancer is covered by Medicare and private insurance plans for qualifying patients.

Previous chest CT scans are very helpful for interpreting your screening scan because they may tell us if a finding is new or stable. Studies performed at Mass General are available to the radiologist at the time of reporting your low-dose CT scan (LDCT). If you have had a previous chest CT at another hospital, please tell your doctor and get a copy of the scan before you have your screening CT.