Lung Nodule? Most are Harmless but Still Need Evaluation

By Leonid Emerel, MD

If you have been diagnosed with lung nodules, you are not alone.

Every year, more than 1.5 million people are told they have lung nodules.

These nodules are usually detected during chest X-rays or CT scans, often when imaging is being performed for another reason.

And while the discovery of a lung nodule can be concerning, it is important to understand that the majority of lung nodules are benign and not cancerous.

At Penn Medicine Princeton Health, patients who have been diagnosed with lung nodules can be evaluated, monitored and treated by a highly skilled team of thoracic surgeons, medical oncologists, thoracic radiologists and advanced practice nurses.

A Common Occurrence

Pulmonary nodules, or lung nodules, are small, round, or oval-shaped growths in the lung. Typically, they measure less than 10 millimeters (about a half inch) in diameter.

Several factors can lead to the formation of lung nodules, including:

• Past infections. Your lungs have a strong immune system, having to defend against all the potential threats inhaled from the outside world. Threats like dust, smoke, fungus, bacteria and viruses. As a result, localized inflammation or scarring may occur, forming nodules.

• Inflammatory conditions. Diseases that cause chronic inflammation can lead to the formation of lung nodules. Nodules are often discovered in people with rheumatoid arthritis, lupus and other autoimmune diseases.

• Cancer. While less common, lung nodules can be an early sign of lung cancer. This is more likely if the nodule is larger, grows over time, or is found in a person with a history of smoking or significant exposure to carcinogens. However, even in high-risk patients, most nodules are not lung cancer.

Lung nodules rarely cause any symptoms, and while they are common, most people will never know they have them.

Next Steps

When a lung nodule is discovered, the next steps depend on multiple factors, including the size, shape, and appearance of the nodule, as well as the patient’s medical history. Here’s how doctors typically approach lung nodules:

• Imaging. CT scans provide more detailed images of lung nodules than standard X-rays. Radiologists look for specific characteristics—such as size, shape, edges, and density—that can help distinguish between benign and malignant nodules.

• Observation. For small (less than one centimeter), benign-appearing nodules, a common approach is “watchful waiting.” This involves regular CT scans over time to monitor for any changes in size or appearance. If the nodule remains stable over a period (usually two years), it is less likely to be cancerous.

• PET Scan.  A PET scan may be used to determine if the nodule is metabolically active, which can be a sign of malignancy. This test can help differentiate between benign and malignant nodules. Yet, in general, PET scans are accurate in only 50% of cases and tend to be less accurate when the nodule is under one centimeter.

• Biopsy. If a nodule appears suspicious or grows over time, a biopsy may be performed. This involves removing a small sample of tissue from the nodule, either through a needle inserted into the lung (needle biopsy) or a bronchoscopy, to be examined under a microscope.

Early Detection  

In some instances, a nodule can be an early sign of lung cancer, which is more likely in older patients who smoke or have a history of smoking.

Other less common risk factors include exposure to asbestos or radon and having a family history of lung cancer.

To detect lung cancer early when it can often be successfully treated, Penn Medicine Princeton Cancer Center offers high-risk individuals low-dose CT screening.

Low-dose CT screening uses low-dose radiation to make a series of detailed pictures of areas in the body. The pictures are made by a computer linked to an X-ray machine that scans the body in a spiral path.  The scan takes just a few minutes and does not require any pre-operative lab work. Results are normally sent to your primary care physician in a matter of days.

The U.S. Preventative Services Task Force recommends annual lung cancer screening with low-dose CT scans in people who meet all these criteria:

• Are 50-80 years old, and
• Currently smoke or have quit in the past 15 years, and
• Have at least a 20 pack-year smoking history. This is the number of packs of cigarettes per day multiplied by the number of years you smoked. For example, someone who smoked 2 packs a day for 10 years [2 x 10 = 20] has 20 pack-years of smoking, as does a person who smoked 1 pack a day for 20 years [1 x 20 = 20].

The American Cancer Society, however, recently updated its guidelines and eliminated the “years since quitting” requirement.

Most insurance typically covers the cost of lung cancer screening for people who meet the criteria. However, individuals should talk with their primary care physician about eligibility and confirm coverage with their insurance carrier prior to the test.

An order from your primary care physician is necessary to schedule a lung cancer screening.

Follow Up

Fewer than 5% of all lung nodules found in all patients turn out to be cancer, according to the American Thoracic Society.

And even in patients who are at the highest risk for lung cancer, an estimated 90% of lung nodules are not cancerous.

Nonetheless, if you have been diagnosed with a lung nodule, be sure to follow up with a pulmonologist or thoracic surgeon. Careful monitoring can help eliminate unnecessary surgery, reduce anxiety and catch lung cancer early when it is most treatable.

To find a physician affiliated with Penn Medicine Princeton Health, call (888) 742-7496 or visit www.princetonhcs.org. 

Leonid Emerel, MD, specializes in thoracic surgery and is a member of the Medical Staff at Penn Medicine Princeton Health.