Lung cancer screening is a CT scan that looks for early signs of cancer in people at high risk

Lung cancer screening uses a special CT scan called a low-dose CT to take detailed pictures of your lungs. It is not the same as a chest X-ray. The scan takes only a few seconds and uses less radiation than a regular CT scan. The goal is to find cancer before symptoms appear, when treatment is most likely to work.

Screening is recommended for people between 50 and 80 years old who have a significant smoking history — usually 20 pack-years or more. A pack-year means smoking one pack per day for one year. If you smoked two packs a day for 10 years, that is 20 pack-years. You do not have to be a current smoker to be screened; former smokers who quit within the last 15 years are also candidates.

Not everyone needs screening. Your doctor can help you decide whether the benefits outweigh the risks based on your age, smoking history, and overall health.

Key Takeaways

  • Low-dose CT screening is recommended for people 50 to 80 years old with a 20 pack-year smoking history or more.
  • The scan takes a few minutes, uses low radiation, and costs between $200 and $500 out of pocket, though insurance often covers it for high-risk people.
  • About 20 percent of screening results show something that needs follow-up, but most of these findings are not cancer.
  • Screening can find cancer early when treatment works better, but it can also find cancers that would never have caused harm, leading to unnecessary treatment.
  • Your doctor should discuss both benefits and risks before you decide to be screened.

Who is a candidate for lung cancer screening

The main criteria are age and smoking history. You are generally a candidate if you are 50 to 80 years old and have smoked at least 20 pack-years in your lifetime. If you quit smoking, you can still be screened if you stopped within the last 15 years.

Some people at lower risk may also benefit from screening. Your doctor might recommend it if you have a family history of lung cancer, a personal history of cancer, or occupational exposure to asbestos or radon. Screening is not recommended for people who have never smoked or who have a life expectancy of less than 5 to 10 years due to other health conditions.

The best way to know whether screening makes sense for you is to talk with your primary care doctor or a pulmonologist. They can review your full medical history and help you weigh the benefits and risks.

What happens during a low-dose CT scan

The scan itself is quick and painless. You lie on a table that slides into a large ring-shaped machine. The machine takes pictures of your lungs from different angles. The whole process usually takes 5 to 10 minutes, and you can breathe normally during most of it. You may be asked to hold your breath for a few seconds while the images are captured.

You do not need to undress completely. Wear loose, comfortable clothing without metal buttons or zippers, and remove any jewelry from your neck and chest. You will be asked to remove your bra if it has metal underwires. There is no injection or dye involved in a low-dose CT scan.

After the scan, you can go home right away. There are no side effects, and you can return to your normal activities when ready.

Understanding your screening results

Results typically come back within one to two weeks. Your doctor will explain what the scan found. Most results fall into one of these categories: no nodules found, nodules that need follow-up, or findings that suggest cancer.

About 20 percent of screening scans show a nodule or other finding that requires follow-up. This does not mean you have cancer. Most nodules are benign (not cancer) and may be scar tissue, old infections, or other non-cancerous growths. Your doctor will decide whether you need another scan in a few months, a more detailed imaging test, or a biopsy.

If the scan shows something that looks like cancer, your doctor will refer you to a specialist for further testing. This might include another CT scan, a PET scan, or a biopsy where a small sample of tissue is removed and examined under a microscope.

The benefits and risks of screening

The main benefit is finding lung cancer at an early stage, when surgery or other treatment is more likely to be successful. Studies show that screening can reduce the risk of dying from lung cancer by about 15 to 20 percent in high-risk smokers.

However, screening also has risks. One is overdiagnosis — finding a cancer that would never have caused symptoms or death. This can lead to surgery, chemotherapy, or radiation that you might not have needed. Another risk is a false positive, where the scan shows something suspicious that turns out not to be cancer after further testing. This can cause anxiety and lead to additional scans or procedures.

Low-dose CT uses radiation, though the amount is small. For most people, the benefit of finding early cancer outweighs this small radiation risk, but your doctor can discuss whether this is true for you personally.

Cost and insurance coverage

The cost of a low-dose CT scan ranges from $200 to $500 without insurance, depending on where you live and which facility performs the scan. Many insurance plans cover screening at no cost to you if you meet the recommended criteria. Medicare covers lung cancer screening for people 50 to 77 years old with a 30 pack-year history who are current smokers or quit within the last 15 years. Some state Medicaid programs also cover it.

Before your scan, call your insurance company or ask your doctor's office to verify what your plan covers. If you do not have insurance, ask the imaging center whether they offer a cash discount or a payment plan.

What to do after screening

If your scan shows no nodules, your doctor will tell you when to return for your next screening — usually in one year. Continue to avoid smoking and secondhand smoke, and talk with your doctor about other ways to protect your lung health.

If follow-up is needed, your doctor will schedule the next step, which might be another CT scan in three to six months, a PET scan, or a biopsy. Do not panic if you need follow-up; most findings are not cancer. Your doctor will explain what each test shows and what the next steps are.

Screening is most effective when combined with other steps to reduce lung cancer risk. Quitting smoking (if you still smoke), avoiding secondhand smoke, and reducing radon exposure in your home all lower your risk.

Frequently Asked Questions

Does screening hurt?

No. The CT scan is painless. You lie still on a table while the machine takes pictures. The only discomfort might be lying in one position for a few minutes, or feeling cold from the machine.

How often do I need screening?

If your first scan shows no nodules, screening is usually repeated once a year. If a nodule is found, your doctor may recommend follow-up scans at shorter intervals — sometimes every three to six months — to watch for changes.

What if I quit smoking years ago — should I still be screened?

Yes, if you quit within the last 15 years and have a 20 pack-year history. Former smokers remain at higher risk for lung cancer even after quitting. Talk with your doctor about whether screening is right for you based on how long ago you quit and your overall health.

Can screening find other lung diseases besides cancer?

Yes. Screening can also detect emphysema, chronic bronchitis, and other lung conditions. If your scan shows signs of these diseases, your doctor may recommend treatment or lifestyle changes to slow their progression.

What should I do if I am nervous about my results?

It is normal to feel anxious while waiting for results or during follow-up testing. Ask your doctor to explain what each finding means and what the next steps are. Many imaging centers and hospitals also offer patient navigators or counselors who can answer questions and provide support.