A small growth on the lung is called a lung nodule. They are very common and may often be benign.
Lung nodules are either considered noncancerous or cancerous. A noncancerous nodule is called benign, and a cancerous lung nodule is referred to as malignant.
Growths that are larger than 3 centimeters are usually called lung masses and typically have a higher chance of being cancerous.
Although it can be frightening for an individual to be told they have a growth in their lung, a lung nodule does not always indicate lung cancer.
Lung nodules are very common. According to the American Thoracic Society, lung nodules can be found on up to 50 percent of adult chest imaging scans. The good news is fewer than 5 percent of lung nodules end up being cancer.
Noncancerous lung nodules can have a variety of causes, including:
- Infection: Infections, such as tuberculosis, can cause inflammation. A group of cells called a granuloma may form around the inflamed area in the lung.
- Non-infectious inflammation: Inflammation that is not related to an infection can also develop in the lung. For instance, rheumatoid arthritis can lead to inflammation in the lungs that results in a nodule.
- Non-cancerous tumors: Non-cancerous growths, such as a fibroma, which is a benign growth of connective tissue, may also develop in the lung.
Although most lung nodules are not cancer, some do turn out to be malignant.
Certain risk factors that increase the chances a lung nodule are associated with cancer. For example, someone who has a history of smoking, is older than 60, or has a family history of cancer has a higher risk of a nodule being cancer.
Larger lung nodules are also more likely to be cancerous.
A lung nodule itself does not often cause any symptoms. Nodules are usually not large enough to interfere with breathing.
In some instances, however, symptoms of the condition that caused the nodule may be present. For example, if a lung nodule is due to lung cancer, symptoms may include:
- shortness of breath
- chest pain
- coughing up blood
- back pain
- weight loss
A CT scan may be performed after an initial X-ray to provide a more detailed image of a lung nodule.
A lung nodule usually shows up on a chest X-ray or a CT scan that has been carried out on a person who has symptoms of a respiratory illness.
The nodule will show up as a spot or shadow on the X-ray. If the nodule was found on a chest X-ray, a CT scan may also be performed. This test can provide more detailed images than an X-ray.
After a lung nodule is discovered, the doctor will look at its size, shape, and general appearance. Certain features may suggest that the nodule is more likely to be cancerous. For example, the larger a growth is, the more likely it is to be cancer.
The location of the nodule, as well as the shape and size, may also increase the chances of it being cancerous. The doctor will also consider the person's medical history, including smoking history, to evaluate the chances of the growth being cancerous.
If a person's risk factors for lung cancer are small and features of the nodule suggest a low likelihood of cancer, doing a biopsy may cause more harm than good. A small lung nodule can be difficult to biopsy, and there are risks, such as bleeding or a collapsed lung.
When the features of the nodule suggest that it may be cancerous, a biopsy may be recommended. A biopsy involves removing a small amount of tissue from the nodule. The tissue can be obtained through a needle biopsy or a bronchoscopy.
A bronchoscopy involves inserting a thin tube into the lung through the mouth or nose and down the windpipe. The tube has a small camera, which allows the doctor to view the nodule. Special tools are then used to obtain a tissue sample.
Another option is a needle biopsy, which involves inserting a needle into the lung through the chest wall. This procedure is usually done with a guided CT scan.
The type of procedure used to get the tissue sample depends on the size and location of the nodule. After the sample is obtained, the tissue is examined under a microscope to look for the presence of cancer cells.
Treatment for lung nodules will often depend on whether the nodule has the features that suggest that it may be cancerous.
A healthcare professional will be able to advise on the best action to take for both noncancerous and cancerous nodules as the treatments will vary.
Treatment for a noncancerous nodule
If the nodule has characteristics that suggest a low chance of cancer, the doctor may recommend taking a wait-and-see approach. The nodule may be monitored with repeat CT imaging scans over time to watch for any changes.
Some doctors may suggest CT scans at regular intervals for a few years to make sure the nodule does not increase in size. The doctor will determine how frequently to perform a follow-up scan based on various factors, such as a person's risk of cancer and the size of the nodule.
If the lung nodule does not change over about 2 years, it is unlikely to be cancer, and further imaging may not be needed.
If a lung nodule is due to an active infection, treatment is based on the condition identified. For example, if the nodule is due to tuberculosis, treatment for the infection will be started.
Treatment for a cancerous nodule
When a lung nodule is cancer, it is most often due to lung cancer, lymphoma, or cancer that has spread to the lung from another organ. If it is determined through a biopsy that the nodule is cancerous, treatment options may vary based on the type and stage of the cancer.
In some instances, when a lung nodule is identified as cancerous, it may be removed through a surgical procedure called a thoracotomy. The procedure involves making a cut through the chest wall into the lung to remove the nodule.
Prevention and outlook
The outlook for people with a lung nodule that is cancerous varies depending on the stage of the disease. In many cases, if lung cancer is found early, the long-term outlook is good.
Lung nodules that are noncancerous have a good outlook and usually do not cause any complications.
Depending on the cause, it may not be possible to prevent lung nodules from occurring. A person can decrease their chances of developing a lung nodule due to lung cancer, however.
Smoking is one of the main risk factors for getting lung cancer. According to the American Lung Association, the main cause of lung cancer in both women and men is smoking. In fact, about 90 percent of lung cancer cases are associated with smoking. As a result, quitting smoking may help reduce the risk of developing lung nodules.