A correct diagnosis is essential to delivering timely and effectivelung cancertreatment.
This article discusses the types of lung cancer and tests commonly used to make a diagnosis.
It explains who should be screened for lung cancer and what the results of any tests typically mean.
Verywell / Hugo Lin
Verywell / Hugo Lin
Who Should Be Checked for Lung Cancer?
Anyone with symptoms of lung cancer should be tested.
It’s also important for people who have risk factors for the disease to be screened.
This is done to evaluate risk factors, such as radon exposure or a smoking history.
It also is used to investigatesymptomsof lung cancer, such as a cough or unexplained weight loss.
Other findings from the exam may include:
Imaging
Your healthcare provider may want imaging studies done.
This will depend on the specific symptoms and findings of your exam.
These tests may include chest X-ray, CT scan, and other imaging.
Chest X-Ray
When lung cancer is suspected, the first test done is usually a chest X-ray.
Lymph nodes, which are a key part of your immune system, may appear enlarged on an X-ray.
Alung massrefers to an abnormality that is larger than 3 centimeters in diameter.
Sometimes the chest X-ray is normal and further tests are needed to look for lung cancer.
Or, ashadow on a lung X-raycould mean there is a spot on the lung.
It also could be a normal part of a person’s chest.
Even if a mass does appear on X-ray, it may bebenignand not related to lung cancer.
Your healthcare provider will want additional tests to confirm any diagnosis.
A chest X-ray alone is not enough to rule out lung cancer.
In fact, about 90% of missed lung cancer diagnoses are due to a reliance on chest X-rays.
CT Scan
ACT scanis frequently done to follow up on an abnormal chest X-ray finding.
CT scans are done by using a series of X-rays to create a three-dimensional view of the lungs.
This approach allows your healthcare team to look at the lungs from more than one angle.
If the CT is abnormal, the diagnosis of lung cancer will still need to be confirmed.
This is done through a biopsy, which is used to examine a sample of lung tissue.
The MRI can deliver high-quality images of what’s going on inside the body.
It’s based on a process that uses radio waves and a magnetic field to create the images.
For this reason, some people may need to avoid having an MRI.
PET Scan
Apositron emission tomography (PET scan)uses radioactive material approved for medical use.
A PET scan will create a colorful, three-dimensional image of the lungs.
This test is usually combined with a CT scan (PET/CT).
Some studies suggest that PET scanning may detect tumors even before they are visible through other studies.
Imaging tests often used to help diagnose lung cancer include the CT scan and MRI.
The PET scan is used to assess an existing tumor, often along with a CT scan.
It may be able to identify tumors earlier than other imaging techniques do.
The biopsy also can reveal what throw in of cancer cells they are.
If lung cancer is diagnosed and spreads, other biopsies may be needed.
Removing the tissue for a biopsy can be done through several procedures discussed below.
If they see abnormal tissues, the biopsy may be taken during this procedure.
Patients are given anesthesia to minimize discomfort.
Endobronchial Ultrasound
Endobronchial ultrasoundis a relatively new technique used for diagnosing lung cancer.
During a bronchoscopy, healthcare providers use an ultrasound probe within the airway to examine the lungs.
They also look at themediastinum, an area of the body that’s between the lungs.
If a tumor is relatively close to the airways, a biopsy can be done by using this technique.
This key in of biopsy can be done when tumors can’t be reached by other techniques.
This lining is called the pleura, and the space is called thepleural cavity.
Thoracentesisis done by using a large needle to remove a small amount of fluid from this space.
This fluid is then tested forcancer cells.
In either case, anesthesia is used at the site to keep the person comfortable.
These samples can help to determine how far a cancer has spread.
This may help your healthcare team to better understand the best possible treatment options.
A PET scan also can be used to look at the mediastinum.
It will often provide similar results while avoiding the need for an invasive surgical procedure.
However, the PET scan may not be as effective in detecting cancer in normal-sized lymph nodes.
It also cannot be used to provide biopsy tissue samples.
A biopsy, or tissue sample, is done to verify a lung cancer diagnosis.
There are several methods, such as bronchoscopy or fine needle aspiration, used to complete this test.
The sample cells are viewed under a microscope to confirm lung cancer and its punch in.
Labs and Tests
During the diagnosis of lung cancer, other tests may be done as well.
These are for related reasons but not a part of a diagnosis itself.
It is the easiest way to confirm a lung cancer diagnosis and pop in.
However, its use is limited to lung cancer cases where the tumors extend into the airways.
Sputum cytology isn’t always accurate and it can miss some cancer cells.
The test is of most benefit when the result is positive.
It is less reliable when the test is negative.
These changes, or mutations, won’t actually diagnose the cancer.
Rather, they are used to identify specific genes that may be involved.
These aren’t mutations that you’re born with or can pass on.
They change as cancer develops and continue to drive its growth.
This is because treatments that target specific genetic changes may be of benefit.
Other treatments are currently being studied inclinical trials.
PD-L1 Testing
PD-L1 is a protein that’s expressed in greater amounts on some lung cancer cells.
Some cancer cells manipulate this protein to evade the immune system.
Drugs known as checkpoint inhibitors work by blocking this action.
They free the immune system to do what it is meant to do.
A PD-L1 test may be done to measure the PD-L1 levels related to your cancer cells.
The results may be used to determine if you may benefit from treatment with any of theseimmunotherapy drugs.
However, the understanding of how they work and who might be treated is still limited.
As part of a lung cancer diagnosis, you also may need other tests related to your condition.
Blood tests may help to confirm how much the cancer has spread.
This tells you much about how aggressive a cancer might be or how far it has spread.
This is essential for your healthcare team to develop the best possible treatment plans.
Small Cell Lung Cancer
Small cell lung cancer (SCLC)accounts for 15% of cases.
While it usually responds fairly well tochemotherapy, it has a poor prognosis.
Small cell lung cancer is broken down into only two stages: limited stage andextensive stage.
These stages are assigned depending on the throw in of lung cancer.
Differential Diagnoses
Your healthcare provider will consider other possibilities when working to make a diagnosis.
The majority of them prove not to be lung cancer.
Summary
A lung cancer diagnosis is typically made through a series of tests.
What’s key to know is that the chest X-ray itself cannot diagnose a lung cancer.
In fact, many lung cancers are missed on a chest X-ray.
As you progress through treatment, some tests may be used to reassess the cancer.
It’s important to follow through to a diagnosis.
Even if it is cancer, your chances of survival are better the sooner that you know.
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