Lung Nodule Causes, Symptoms, and Treatment

Table of ContentsView AllTable of ContentsWhat Is a Lung Nodule?SymptomsCausesRisk FactorsDiagnosisCancerTreatment

Table of ContentsView All

View All

Table of Contents

What Is a Lung Nodule?

Symptoms

Causes

Risk Factors

Diagnosis

Cancer

Treatment

Most lung nodules are not cancerous. However, it’s essential to follow through on getting a diagnosis, even if you’ve never smoked.

This article will explain what causes lung nodules, how they are diagnosed, the risk of your lung nodule being cancerous, and how they are treated.

Verywell / Emily Roberts

Lung nodules look like spots on X-rays and CT scans. They are sometimes also referred to as “coin lesions” because they often have a round, coin-like shape.

Lung nodules are defined as being 3 centimeters (cm) or 1.2 inches in diameter or less. They need to be at least 1 cm in size before they can be seen on a chest X-ray. CT scans provide more finely detailed images and can detect nodules as small as 1 to 2 millimeters.

Lesions larger than 3 cm are referred to aslung masses, not nodules. Lung masses have a greater risk of being malignant.

Symptoms of Lung Nodules

Lung nodules are so small that they don’t tend to cause breathing problems or other symptoms. That’s why they’re usually found incidentally when a chest X-ray is done for some other reason.

If symptoms are present, they may include:

Lung Scarring: What to Know

Lung Nodule Causes

Lung nodules can bebenign(noncancerous) ormalignant(cancerous). Most benign lung nodules result from inflammation due to infections or illnesses.

When your lungs become inflamed, tiny masses of tissue can develop.  Over time, the clumps can harden into a nodule on your lung.

The causes of most benign lung nodules include:

Lung nodules are common. They are found on around .1 to .2% of routine chest X-rays and on about 13% of non-screening chest CT scans.Each year, around 1.5 million adults in the United States will have a lung nodule identified.

Other, less-common causes of a lung nodule include:

The most common causes of malignant lung nodules are primary lung cancer that started in the lung or metastatic cancers from other regions of the body that have spread to the lungs.

Carcinoid tumors, a kind of neuroendocrine tumor, are usually benign tumors except in rare cases when the tumor is metabolically active and called malignant carcinoid.

Some illnesses you may have had and lifestyle factors may increase your risk of having lung nodules. Some of these include:

Certain environmental conditions can also predispose you to getting lung nodules. If you live in the southwest or have traveled to certain countries, a fungal or parasitic infection may be considered as the potential cause of your lung nodule.

There are three diagnoses for lung nodules: noncancerous, cancerous, or indeterminate. Indeterminate nodules cannot be definitively defined as benign or malignant.

When healthcare providers see a lung nodule on an X-ray, the first thing they usually do is get any lung imaging tests you may have had in the past to compare them.

If the nodule has been there for a long time and hasn’t changed, it’s probably not cancer. Further tests may not be needed. However, if you don’t have any prior X-rays for comparison, or if the nodule has changed or is new, further tests may be needed.

If a nodule does not appear to have changed or your healthcare providers believe that there’s a low risk of it being cancer, they may take a “wait and watch” approach. They will have you get another imaging test, usually in six months to a year. Single, solitary nodules that have remained unchanged for two or more years do not generally need any further workup.

Imaging Tests

If your nodule is found on a chest X-ray, you may have a computed tomography (CT) scan of your chest. CT scans can provide detailed images and are taken at different angles.

Other tests healthcare providers may order include:

Biopsy

If your nodule has changed in size or appearance, if your diagnosis is uncertain, or if there’s a chance that your nodules might be metastatic cancer from another tumor, a sample of your nodule may be required to determine whether it is malignant.

There are different biopsy methods:

Research suggests that even when a lung nodule is found in a person who might be expected to have lung metastases, only half of the nodules were found to be metastases when biopsied.Up to 25% were primary lung cancer.

Lung Nodules and Cancer

There’s a less than 1% chance that a nodule smaller than 5 mm will be cancerous.However, a person’s actual risk depends on a variety of factors. In people younger than 35, malignancies are very uncommon, while half of all lung nodules in people over age 50 are cancerous.

Here are other factors that can play a role in whether lung nodules that show up on an X-ray are noncancerous or cancerous.

Low Risk of Lung CancerUnder age 35Nodule is small (less than 3 cm in diameter)Patient is a nonsmoker (and has never smoked)No exposure to toxins in the workplaceNo history of lung cancer among family membersNo other signs or symptoms of lung cancerNodules are smooth and round in shapeNodules are only partly solidNodules do not get bigger over timeNodules are calcified (contain calcium deposits)Interior of nodule is cavitary (darker on X-rays)Only one or a few nodules are presentHigh Risk of Lung CancerOver age 50Nodule is larger than 3 cm in diameterPatient smokes or is a former smokerExposure to occupational toxins such as asbestos or radonFirst- or second-degree relative with lung cancerPresence of lung cancer symptoms such as persistent cough or shortness of breathNodules are spiculated (have irregular or lobe-shaped borders)Nodules are solidNodules grow rapidly (on average doubling in size in four months)Nodules show no signs of calcificationNodules are not cavitaryPresence of multiple nodules (may indicate cancer metastases to the lungs)

Low Risk of Lung CancerUnder age 35Nodule is small (less than 3 cm in diameter)Patient is a nonsmoker (and has never smoked)No exposure to toxins in the workplaceNo history of lung cancer among family membersNo other signs or symptoms of lung cancerNodules are smooth and round in shapeNodules are only partly solidNodules do not get bigger over timeNodules are calcified (contain calcium deposits)Interior of nodule is cavitary (darker on X-rays)Only one or a few nodules are present

Under age 35

Nodule is small (less than 3 cm in diameter)

Patient is a nonsmoker (and has never smoked)

No exposure to toxins in the workplace

No history of lung cancer among family members

No other signs or symptoms of lung cancer

Nodules are smooth and round in shape

Nodules are only partly solid

Nodules do not get bigger over time

Nodules are calcified (contain calcium deposits)

Interior of nodule is cavitary (darker on X-rays)

Only one or a few nodules are present

High Risk of Lung CancerOver age 50Nodule is larger than 3 cm in diameterPatient smokes or is a former smokerExposure to occupational toxins such as asbestos or radonFirst- or second-degree relative with lung cancerPresence of lung cancer symptoms such as persistent cough or shortness of breathNodules are spiculated (have irregular or lobe-shaped borders)Nodules are solidNodules grow rapidly (on average doubling in size in four months)Nodules show no signs of calcificationNodules are not cavitaryPresence of multiple nodules (may indicate cancer metastases to the lungs)

Over age 50

Nodule is larger than 3 cm in diameter

Patient smokes or is a former smoker

Exposure to occupational toxins such as asbestos or radon

First- or second-degree relative with lung cancer

Presence of lung cancer symptoms such as persistent cough or shortness of breath

Nodules are spiculated (have irregular or lobe-shaped borders)

Nodules are solid

Nodules grow rapidly (on average doubling in size in four months)

Nodules show no signs of calcification

Nodules are not cavitary

Presence of multiple nodules (may indicate cancer metastases to the lungs)

Lung Cancer Screening

U.S. health officials recommend screening every year for lung cancer if you are between the ages of 50 and 80, still smoke, have quit within the last 15 years, or have a20-pack-year smoking history.

Pack-year smoking history is a way to gauge how much you’ve smoked in your lifetime. It means that if you smoked one pack a day for 20 years or two packs a day for 10 years, you should get tested every year for lung cancer.

The recommendations call for using low-radiation-dose CT scans. Screening with chest X-rays has not been shown to reduce the risk of dying from lung cancer.

As with any screening test, there is a risk of false positives, and it’s common to find nodules on CT screening. Finding nodules does not always mean cancer. In fact, most small nodules turn out to be benign.

Medication

If your lung nodule is cancerous, your healthcare provider may choose to treat you with chemotherapy. Chemotherapy drugs target fast-growing cancer cells. Depending on your type of lung cancer and its stage, you may also receive drugs such as:

Video-Assisted Thoracic Surgery (VATS)

This is a minimally invasive surgery that can remove cancerous nodules or non-cancerous nodules that are causing symptoms.

During this procedure, a small tube with a camera at the end is inserted into a small incision between the ribs. The surgeon can remove the nodule with instruments inserted through one or two other small incisions.

Because it is minimally invasive, people who undergo VATS usually recover faster and have less pain than people who undergo more invasive procedures. Hospitalization time is also generally shorter and complications are less likely.

Thoracotomy

A thoracotomy is an open-chest surgery that involves spreading the ribs apart in order to access the lungs. Thoracotomy is much more invasive than VATS and has a longer recovery time. However, it has advantages such as giving the surgeon better visibility of the lungs and any lesions that might have been missed on an imaging scan.

Summary

Lung nodules are small lesions in the lungs. They are usually found with an imaging scan such as an X-ray or CT scan.

Lung nodules can have many different causes, including infections, scarring, and malignancies. Because of the possibility that a lung nodule might be cancerous, your healthcare provider will want to do further testing to rule this out.

Benign lung nodules don’t need to be treated unless they are causing symptoms. If a lung nodule is cancerous, it may be treated with medication, surgery, or a combination of both.

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Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

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