How Common Are Lung Nodules?

Often called a “spot on the lung,” a lung nodule is an area of dense tissue that shows up as a white spot or shadow on a chest x-ray or CT scan. A recent study of more than 10,000 nonsmokers found the number of people with one or more lung nodule was higher than expected.

At a glance, this news might seem concerning for nonsmokers. However, Andrew Dunatchik, MD, a University Hospitals pulmonologist, shares why you shouldn’t worry in most cases and who should consider screening.

Most Lung Nodules Are Harmless

Most lung nodules are made up of small clumps of immune cells left over from a past fungal or bacterial infection. The vast majority of lung nodules – more than 95 percent – aren’t caused by cancer.

The most common causes of lung nodules include:

• Respiratory system infections, like pneumonia or fungal infections.
• Primary lung diseases such as chronic obstructive pulmonary disease (COPD) and asthma.
• Autoimmune diseases, including rheumatoid arthritis and sarcoidosis.
• Lung cysts and abscesses.
• Air irritants or pollutants.

Who Should Get Screened for Lung Nodules?

“While this is the first study to look for lung nodules in nonsmokers, we already know that chest X-rays and CT scans show one or more lung nodules in about half of all adults,” says Dr. Dunatchik.

Because most lung nodules are benign and will never cause any problems, doctors don’t specifically screen for them. Instead, they screen for lung cancer in people with a current or previous history of smoking. This includes people age 50 and older who:

• Are current smokers.
• Are former smokers who quit within the last 15 years.
• Smoke/smoked at least 20 pack-years (A pack-year measures how much someone smokes over time. For example, 1 pack-year is equal to smoking 1 pack a day for 1 year, or 2 packs a day for 6 months, and so on. Calculate yours here.)

The scan should be repeated yearly, or more frequently depending on the results.

Lung Nodule Treatment

Most benign lung nodules do not cause symptoms or require medical treatment. Follow-up imaging and monitoring of a lung nodule isn’t always required, especially if the nodule is very small (under 4 millimeters).

For larger nodules or for patients with risk factors, a doctor may recommend follow-up imaging. These risk factors include:

• Current or former smoker.
• Exposure to secondhand smoke.
• Exposure to radon, asbestos, diesel fume exhaust or other cancer-causing agents.
• Personal or family history of lung cancer or other cancers.
• Previous radiation therapy to the lungs.

“The most important factor in whether to be concerned about a lung nodule is a change in size over time,” says Dr. Dunatchik. “If follow-up imaging shows that a smaller lung nodule hasn’t grown, or has shrunk or disappeared, that’s very reassuring because cancer doesn’t go away on its own. If a nodule has grown, we may take a biopsy to determine if it’s cancerous or not.”

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The UH Respiratory Health Institute provides a focused, collaborative approach for all respiratory conditions – from acute pulmonary disorders to even the most complex chronic pulmonary disease. Our team of lung experts offers options for pulmonary care close to home with multiple locations across Northern Ohio.