What You Need to Know About Lung Nodules and When to Worry

If you’ve been told you have a lung nodule, it’s natural to feel concerned. Before jumping to conclusions, it’s important to understand what lung nodules are, how common they are and when they actually require closer attention.

Richard Anderson, MD, a cardiothoracic surgeon at OSF HealthCare, shared what you need to know about and when to worry about lung nodules.

What Are Lung Nodules?

A lung nodule is a small, round or oval-shaped growth in the lung. Most of the time, these nodules are typically found during routine imaging tests like X-rays or CT scans. Lung nodules can be caused by a variety of things, including infections, inflammation or scar tissue. In some cases, they may represent early signs of cancer, but that’s less common than you might think.

Are Lung Nodules Common?

“Nodules are very common,” Dr. Anderson said.

Lung nodules are especially common as people age or if they have a history of smoking or exposure to environmental irritants.

Nodules are found in up to 50% of adults who undergo a chest CT scan. The vast majority are benign, or non-cancerous, and never cause problems.

When to Worry About Lung Nodules

Many times, lung nodules are nothing to worry about. Your doctor can help you determine when to be cautious and a plan forward if there is cause to worry.

When to worry often depends on several factors, including:

• The size of the nodule
• Whether the nodule is growing over time
• Your medical history – especially smoking history
• The shape, edge and density of the nodule on imaging
• Whether you have symptoms like a persistent cough or unexplained weight loss

What Size Nodule Should Cause Worry?

• Is a four-millimeter (mm) lung nodule serious? A four mm lung nodule is generally considered low risk, especially if you’re a non-smoker and have no history of cancer. In many cases, your doctor will recommend monitoring it with follow-up imaging rather than immediate biopsy or surgery.
• Is a six mm lung nodule serious? As nodules get slightly larger, doctors may recommend more frequent monitoring. So, it’s more likely to require routine follow-up to make sure it doesn’t grow.
• Is a seven or eight mm lung nodule serious? These sizes fall into a more moderate risk category. Your doctor may recommend follow-up imaging every few months or even a PET scan, depending on your individual risk factors.
• Is a ten mm lung nodule serious? A ten mm lung nodule – or one centimeter – is typically more concerning than smaller nodules. While it still could be benign, the risk of cancer increases slightly with size. At this stage, your care team may recommend more advanced testing, such as a biopsy or PET scan, to rule out malignancy.

Can Lung Nodules Disappear?

Yes, lung nodules can disappear, especially if they’re caused by infections or inflammation. Some nodules may shrink or resolve completely on their own. This is one reason why doctors often recommend a “watch and wait” approach for smaller nodules instead of jumping straight to invasive testing.

What to Do If You Have a Lung Nodule

“When nodules are less than seven millimeters, they are usually just followed with repeat imaging,” Dr. Anderson said. “The radiologist that reviews the lung screening exam provides a general rating based on the size, shape and appearance of the nodule. That helps decide what the next step should be – either continued CT screening or more advanced testing.”

“Once a nodule grows or changes in shape, more diagnostic tests need to be done,” Dr. Anderson said.

If you’ve been told you have a lung nodule, try not to panic. Instead:

• Talk to your doctor about your individual risk factors.
• Follow up with any recommended imaging tests.
• Ask questions about the size, shape and appearance of the nodule.
• Discuss next steps based on your specific health history.

Early detection and monitoring can make a big difference. Staying informed and following your care team’s guidance is the best path forward.