How is lung cancer diagnosed?

Published: Tuesday, June 25, 2024
Critical Care Medicine, Pulmonology

The American Cancer Society estimates that 234,580 new cases of lung cancer will be diagnosed in 2024, including more than 7,000 cases here in Georgia. But how is lung cancer diagnosed?

When you think about cancer, some of the most common cancers probably come to mind—like breast cancer and colorectal cancer. Thanks to innovations over the past century, we now have viable screening methods for those types of cancer, allowing many cases to be found long before symptoms ever develop.

Those cancer screenings are recommended widely. The U.S. Preventive Services Task Force (USPSTF) recommends all women have routine mammograms beginning at age 40, for example, while colorectal cancer screening is recommended for everyone beginning at age 45.

You might not realize, however, that there’s a screening for lung cancer. It is not as widely known and recognized, but it provides a strategic tool for diagnosing many cases of lung cancer. Keep reading to learn how it works, as well as other ways lung cancer is diagnosed.

What to know about screening for lung cancer

The USPSTF recommends lung cancer screenings for adults who:

  • Are between the ages of 50 and 80
  • Currently smoke or have smoked within the past 15 years
  • Have a 20 pack-year smoking history

A “pack-year” is defined as smoking one pack of cigarettes daily for one year. Someone who smoked two packs per day for 10 years would have a 20 pack-year history, as would someone who smoked one pack per day for 20 years.

Lung cancer screening consists of a low-dose computed tomography (CT) scan of the chest. CT scans provide more detailed images of the chest than standard X-rays, making them more suitable for catching small abnormalities that could be lung cancer.

If abnormalities are detected during screening, further testing will be used to confirm a diagnosis. The onset of lung cancer screening means that many cases of lung cancer are now detected early when they’re most easily treated.

The symptoms of lung cancer

How is lung cancer detected in those who don’t meet the criteria for routine screening?

In some cases, a suspicious lung nodule may be detected during a CT scan or another imaging scan for a different medical condition altogether. In other cases, imaging scans and other diagnostic tests may be ordered when a person is exhibiting symptoms that could be related to lung cancer.

Lung cancer symptoms may include:

  • A chronic cough that worsens rather than improving
  • Bloody sputum (mucus)
  • Chest or upper back discomfort
  • Difficulty swallowing
  • Fatigue
  • Frequent respiratory infections
  • Hoarseness
  • Loss of appetite
  • Shortness of breath
  • Swelling in the face or neck
  • Weight loss with no known cause
  • Wheezing

Symptoms can vary, somewhat, depending on which type of lung cancer and therefore as noted above, these are the symptoms to consider in the evaluation of lung cancer.

In many cases, early-stage lung cancer doesn’t cause any noticeable symptoms. Symptoms become more likely in later stages.

How lung cancer is diagnosed

A CT scan can find abnormalities such as, but not limited to, something called a lung nodule during lung cancer screening. Potentially, but not all, nodules can be early lung cancers. An incidental finding during other imaging for another condition can find a pulmonary lung nodule or abnormality. In many cases, small nodules are monitored with follow-up imaging scans, often after 6 months or a year.

If a lung nodule is detected during a lung cancer screening or is an incidental finding during imaging for another condition, your medical provider can recommend next steps. In many cases, small nodules are monitored with follow-up imaging scans, often after six months or a year.

That’s because the vast majority of lung nodules are not cancer. In fact, up to 95 percent of lung nodules are benign, or noncancerous. Taking a “watch and wait” approach to a nodule lessens the risk of undergoing unnecessary testing and treatment.

If a lung nodule grows between scans or is larger to begin with, further diagnostic testing will be used to determine whether the nodule is cancerous. To diagnose potential cases of lung cancer, your provider or a specialist such as a pulmonologist or cardiothoracic surgeon may use several different tools:

  • CT scans, which use X-rays to capture multiple detailed images, can help identify the size, shape, position, and other characteristics of lung nodules.
  • Positron emission tomography (PET) scans, which involve the intravenous infusion of a radioactive substance, are used to identify potentially cancerous cells in the body. Cancer cells grow rapidly, so they absorb more radiation than surrounding cells, making them light up or glow on a PET scan. Because infection and inflammation can also cause spots in the body to light up on a PET scan, this test isn’t used as a standalone diagnostic tool.
  • Sputum cytology, which is the analysis of the cells in sputum under a microscope, is less commonly used but may be helpful in diagnosing some cases of squamous lung cancer.

While all of these tests can provide helpful information if lung cancer is suspected, the only definitive way to diagnose lung cancer is a tissue biopsy. There are multiple types of biopsies, but all involve examining a sample of lung cancer tissue to determine whether it’s cancerous.

The type of tissue biopsy that’s recommended for diagnosing lung cancer will depend on a number of factors, including the location of the suspicious nodule.

The tools used for biopsy include bronchoscopy such as robotic navigational bronchoscopy, endobronchial ultrasound-guided bronchoscopy, video-assisted thorascopic surgery, and CT-guided transthoracic needle biopsy.

Bronchoscopy, which involves inserting a small tube in the mouth or nose, down through the trachea, and to the lungs to take a sample of tissue, is the most common type of biopsy for lung cancer. Other types of tissue biopsy, including video-assisted thoracoscopic surgery, may be used when a nodule is in a part of the lung that would be difficult to access using bronchoscopy.

If a biopsy confirms that a lung nodule is cancerous, additional testing may be used to stage the cancer, allowing your providers to see whether it has spread. Your treatment plan will be based on the specific type of lung cancer, as well as its stage.

Treatment for lung cancer typically involves surgery to remove the lung nodule, but may also include chemotherapy or immunotherapy, either before surgery to shrink the nodule or after surgery to fully eradicate any remaining cancer cells. Northeast Georgia Medical Center offers minimally invasive robotic thoracic surgery for the removal of lung nodules.

Chemotherapy, immunotherapy and radiation therapy are additional treatment options for individuals with lung cancer.

Your care team, which may include a surgical oncologist and a medical oncologist, will recommend a treatment plan based on your specific needs.

Learn more

If you or a loved one have been diagnosed with lung cancer, the Cancer Services team at NGMC is here to help. NGMC has a coordinated team approach, among many specialties, working together to give you the best options for individualized care. Call 770-525-5349 or click here to learn more.