Lung cancer is a type of cancer that begins in the lungs and has the potential to spread to other organs in the body.
Early lung cancer symptoms can be subtle, but the earlier it is diagnosed, the better the treatment options and potential outcomes you might have.
Let us now dive into the diagnostic tests for lung cancer, because knowing more about these tests can help you take control of your health and educate others as well.
Lung cancer tests
A few lung tumours can be detected through screening, but the majority of lung cancers are discovered after they cause problems. The actual diagnosis of a lung tumour is made in the lab by examining a sample of lung cells. Consult your doctor if you have any symptoms or warning signs of lung cancer.
Based on your symptoms, medical history, and associated risks, your doctor may perform a physical examination.
On physical examination, if you have any of these symptoms, your doctor may suspect lung cancer:
- Weak breathing
- Abnormal lung sounds
- Dullness of chest tapping
- Swollen lymph nodes above your collarbone
- Your abdomen has a mass
- Droopy eyes
- Unequal pupils
- One-arm weakness
- Swelling of the face
- Arms, neck, or chest vein expanded
Additional tests will be performed, if necessary, based on the outcomes of your examination and history.
Imaging tests to detect lung cancer
Imaging tests create images of the inside of your body by using magnetic fields, X-rays, sound waves, or radioactive substances. Imaging tests may be performed both prior to and following a lung cancer diagnosis for a variety of reasons, including:
- To examine any suspicious areas that could be cancerous
- To determine how far cancer has spread
- To help determine whether or not treatment is responding
- To identify indicators of cancer recurrence after treatment
X-ray of the chest
A chest x-ray is frequently the very first test performed by your doctor to check for any abnormalities in the lungs. If anything suspicious is discovered, the doctor might request additional tests.
A computed tomography (CT) scan uses X-rays and creates detailed cross-sectional pictures of your body. A CT scanner, unlike a regular X-ray, takes numerous pictures, which are then combined by a computer to reveal a portion of your body being investigated.
A CT scan is much more likely than a routine chest x-ray to reveal lung tumours. It can also reveal the dimensions, shape, and location of any lung tumours, as well as swollen lymph nodes that may contain cancer that is spreading. This test additionally has the potential to detect masses or lumps in the adrenal glands, brain, liver, and other organs that may be caused by the spread of lung cancer.
Magnetic resonance imaging
Magnetic resonance imaging (MRI) scans, similar to CT scans, provide detailed images of the body’s soft tissues. MRI scans, on the other hand, employ radio waves and powerful magnets rather than X-rays. MRI scans are frequently performed to identify possible lung cancer spread to the spinal cord or brain.
Positron emission tomography (PET scan)
To perform a PET scan, FDG (a radioactive form of sugar) is injected into the blood. This radioactive substance accumulates primarily in cancer cells.
PET/CT scan: A PET scan is commonly used in combination with a CT scan, with the help of specialised machinery which makes it possible to perform both scans simultaneously. This allows the doctor to compare areas of increased radioactivity on the PET scan against a more detailed image on the CT scan. This is the most commonly used PET scan type for lung cancer patients.
To perform a bone scan, a small quantity of radioactive material (low-level) is injected into the blood. If cancer has advanced to the bones, a bone scan could help determine whether it has spread. This test, however, is rarely required since PET scans can generally detect whether tumours have advanced to the bones.
Lung cancer diagnostic tests
Although the symptoms and test results may strongly recommend that an individual has lung cancer, the confirmatory diagnosis is made by examining lung cells in the laboratory.
Cells can be obtained from the secretions of the lung (mucus coughed up from the lungs), fluid drawn from the region around the lung (the procedure is called thoracentesis), or a suspected area with the help of a surgery or needle (the procedure is called a biopsy). The situation determines which test(s) are to be used.
A sample of lung secretions (mucus coughed up from the lungs) is examined in the laboratory in order to determine whether it contains cancerous cells. The best approach to do this is to collect early morning samples for three days consecutively.
If fluid has accumulated around the lungs (a condition known as pleural effusion), a doctor can obtain some of it to determine whether it is the result of cancer spreading to the lung lining (pleura). Certain other conditions, including infection or heart failure, might also contribute to the fluid build-up.
A thoracentesis involves numbing the skin and inserting a hollow needle between the ribs to help drain the fluid. This fluid is tested for cancer cells in the lab.
If a malignant pleural effusion is diagnosed and is causing breathing difficulties, a repeat thoracocentesis may be performed to remove excess fluid and ease breathing.
A hollow needle is frequently used by doctors to obtain a small specimen from a suspicious area. The fact that needle biopsies do not necessitate a surgical incision is an additional benefit. The disadvantage would be that they remove just a tiny portion of tissue, which in some cases may not be enough to make a diagnosis and perform additional tests on cancer cells to help physicians choose anticancer drugs.
Fine needle aspiration biopsy (FNA biopsy)
To aspirate cells and tiny fragments of tissue, the doctor uses a very thin, hollow needle. A FNA biopsy could be performed to check for cancerous cells in the lymph nodes located between the lungs.
Transtracheal or transbronchial FNA
Transtracheal or transbronchial FNA is performed by inserting a needle into the trachea or bronchi during endobronchial ultrasound or bronchoscopy.
A bigger needle is inserted to obtain one or more tiny cores of tissue. Since core biopsy samples are larger than fine-needle aspiration biopsy specimens, they are often preferred.
Transthoracic needle biopsy
If the suspected tumour is in the outer portion of the lung, the biopsy needle is inserted into the chest wall through the skin. Local anaesthesia may be used to numb the area of the needle puncture. The needle is then guided into the area while the doctor is observing the lungs with the help of a fluoroscopy or a CT scan. One of the procedural complications of this type of biopsy is pneumothorax.
A flexible tube with a light (called a bronchoscope) is inserted into the large lung airways through the nose or mouth. This test can help the physician see tumours or take a specimen to determine whether cancer cells exist.
Tests to see if lung cancer has spread to the chest
If lung cancer is discovered, it is often necessary to determine whether it has advanced to the lymph nodes in the nearby areas or the mediastinum. This can have an impact on a person’s treatment options. Different types of tests may be performed to detect the spread of cancer.
Endobronchial ultrasound and endoscopic oesophageal ultrasound
Endobronchial ultrasound may be performed to check the lymph nodes and certain other nearby structures between the lungs to determine whether a biopsy is required with the help of a bronchoscope attached to the ultrasound device at its tip.
The endoscopic oesophageal ultrasound test is quite similar to an endobronchial ultrasound, but it uses an endoscope. It is passed through the throat and into the oesophagus, where it serves as a guide to assess and sample nearby lymph nodes.
Mediastinoscopy and mediastinotomy
These procedures may be carried out in order to examine and facilitate the collection of specimens from the mediastinum (the area between the lungs). The primary distinction between the two is the size and location of the incision.
A small cut in the chest is made. The surgeon then examines the space between the chest wall and the lungs with a lighted, thin tube connected to a camera and screen. Small tumours on the lung or the chest wall linings can be seen by the surgeon, and the tissue can be removed to be examined under a microscope and to determine whether a tumour is spreading to other tissues or organs.
Lung function tests
Pulmonary (lung) function tests (PFTs) are frequently performed after the diagnosis of lung cancer is made in order to determine the capacity of the lung functioning. This is particularly important if surgery is a treatment option, because surgery for lung cancer may necessitate the removal of a portion or the entire lung; so, it is essential to understand very well how your lungs work beforehand so that the surgeon can determine whether surgery is a viable option and, if yes, how much of the lung can be safely removed.
Molecular tests for gene changes
In some cases, particularly in non-small cell lung cancer, a physician may investigate particular gene changes in cancer cells that could indicate that certain targeted drugs could help treat cancer. For instance, changes in the KRAS gene cause 20%–25% of non-small cell lung cancer (NSCLC) to produce an abnormal KRAS protein, which aids cancer cell growth and spread. NSCLCs with this mutation are frequently adenocarcinomas that are resistant to drugs such as EGFR inhibitors and are most commonly found in smokers.
A note by LivLong
Lung cancer early diagnosis and management are critical for improving patient outcomes. The stage of lung cancer at the time of diagnosis is essential in determining the best treatment plan, which may include lung cancer chemotherapy, radiation therapy, surgery, or a combination of some of these. Because it does not show symptoms in the early stages, the average age of lung cancer diagnosis is high, emphasising the significance of regular screening and maintaining good lung health. A specialist for lung care can provide expert assistance and guidance to those with lung cancer. While there is currently no cure for lung cancer, patients can improve their quality of life and potentially extend their lifespan with proper treatment and management.
How is lung cancer usually diagnosed?
Lung cancer is typically detected using a combination of imaging tests such as X-rays, MRIs, or CT scans, and a biopsy of the suspicious tissue. This procedure aids in identifying the dimensions, position, and appearance of any abnormalities in the lungs, in addition to confirming the presence of cancerous cells.
How is stage 1 lung cancer diagnosed?
A stage 1 lung tumour is a relatively small mass that is confined to its origin, that is, it has not spread to other parts of the body. The majority of early lung cancers have no symptoms and can be discovered at the time of routine screening. Although uncommon, the following symptoms may occur when a stage 1 lung tumour causes symptoms:
• Persistent cough
• Worsening of chronic cough
• Coughing up blood-tinged mucus
• Breathing difficulty
• Continuous chest pain
• recurring lung infections
What questions should I ask when diagnosed with lung cancer?
These are some of the questions you may want to ask:
• What type of lung cancer am I suffering from?
• What is my cancer's stage, and what does it imply in my case?
• Will I require any additional testing before we can make a treatment decision?
• Has the cancer been tested for gene mutations that could aid you in deciding on my treatment options?
• Who can assist me if I am worried about the expenses and health insurance coverage for my diagnosis and treatment?
• What are the treatment options, and are there any potential side effects from the treatments?
It is advised that you should clarify all your questions and doubts prior to beginning any treatment.
Why is it often so difficult to diagnose lung cancer?
Lung cancer can be challenging to identify in its early stages because it often produces few if any, symptoms. By the time symptoms appear, cancer may have advanced to an advanced stage, making treatment more difficult.