Tests to confirm diagnosis for lung cancer
If a tumour is suspected after an x-ray or CT scan, you will need further tests to work out whether it is lung cancer.
Learn more about:
- Other samples
- Molecular testing
A biopsy is the usual way to confirm a lung cancer diagnosis. A small sample of tissue is taken from the lung and/or nearby lymph nodes, then a specialist doctor called a pathologist examines the sample under a microscope. There are various ways to take a biopsy.
Using a CT scan for guidance, the doctor inserts a needle through the chest wall to remove a small piece of tumour from the outer part of the lungs. You will be observed for a few hours afterwards, as there is a small risk of damaging the lung.
This allows the doctor to look inside the large airways (bronchi) using a bronchoscope, a flexible tube with a light and camera. You will have sedation or a general anaesthetic, then the doctor will pass the bronchoscope into your nose or mouth, down the trachea (windpipe) and into the bronchi. If the tumour is near the bronchi, samples of cells can be collected with a washing or brushing technique. During “washing”, fluid is injected into the lung and removed for examination. “Brushing” uses a brush-like instrument to remove some cells from the bronchi.
This is a bronchoscopy that allows the doctor to see cancers deeper in the lung. It can also take samples of cells from a tumour or a lymph node in the middle of your chest or next to the airways, or from the outer parts of the lung.
You will have sedation or a general anaesthetic, and the doctor will use a bronchoscope with a small ultrasound probe on the end. The ultrasound probe uses soundwaves to create pictures that show the size and position of the tumour and allow the doctor to measure it.
After an EBUS, you may have a sore throat or cough up a small amount of blood. These side effects usually pass quickly, but tell your medical team how you are feeling so they can monitor you.
This is not used as often as other biopsy methods, but is sometimes used if a sample is needed from the lymph nodes found between the lungs (mediastinum). You will have a general anaesthetic, then a small cut (incision) will be made in the front of your neck and a thin tube passed down the outside of the trachea. A mediastinoscopy is usually a day procedure, but you may need to stay overnight in hospital for observation.
If other tests are unable to provide a diagnosis, you may have a thoracoscopy. This uses a thoracoscope, a tube with a light and camera, to take a tissue sample from the lungs. It is usually done under general anaesthetic with a type of keyhole surgery called video- assisted thoracoscopic surgery (VATS). After VATS, you will have a drain coming from your side and stay in hospital for a few days. Sometimes a simpler procedure called a medical thoracoscopy can be done as a day procedure under sedation.
A sample of cells may be taken from the lymph nodes in the neck with a thin needle. This is done using ultrasound for guidance.
|A new technique known as liquid biopsy involves taking a blood sample and examining it for signs of disease. At this stage, however, liquid biopsy is not a routine way to diagnose lung cancer.|
In some circumstances, such as if you aren’t well enough for a biopsy, mucus or fluid from your lungs may be checked for abnormal cells.
This test examines a sample of mucus (sputum) from your lungs. Sputum is different to saliva as it contains cells that line the airways. To collect a sample, you will be asked to cough deeply and forcefully into a container. This can be done in the morning at home. The sample can be refrigerated until you take it to your doctor, who will send it to a laboratory to check under a microscope.
Also known as pleurocentesis or thoracentesis, a pleural tap is a procedure to drain fluid from around the lungs. While it is often done to ease breathlessness, the fluid can be tested for cancer cells. It is mostly performed under local anaesthetic using ultrasound for guidance. As with all biopsies, the results need to be interpreted along with the results of physical examination, blood and breathing tests, and imaging tests such as x-ray and CT scan.
The biopsy sample may be tested for genetic changes or specific proteins in the cancer cells (biomarkers). The tests are known as molecular tests and help work out which drugs may be most effective in treating the cancer.
Genes are found in every cell of the body and are inherited from both parents. If something triggers the genes to change (mutate), cancer may start growing. A mutation that occurs after you are born is not the same thing as genes inherited from your parents.
The most common genetic mutations seen in non-small cell lung cancer are changes in the EGFR (epidermal growth factor receptor), ALK (anaplastic lymphoma kinase) and ROS1 genes. Some mutations can be treated with medicines known as targeted therapy, but others do not yet have a targeted therapy available.
Certain proteins found in some types of non-small cell lung cancer suggest that the cancer may respond to immunotherapy. These include proteins known as PD-1 and PD-L1.
Dr Henry Marshall, Thoracic Physician, The University of Queensland Thoracic Research Centre, The Prince Charles Hospital, QLD; Dr Naveed Alam, Thoracic Surgeon, St Vincent’s Melbourne and Epworth Richmond Hospitals, VIC; A/Prof Martin Borg, Radiation Oncologist, GenesisCare, SA; Dr Lisa Briggs, Consumer; Kirsten Mooney, Thoracic Cancer Nurse Coordinator, WA Cancer & Palliative Care Network, WA; Claire Mulvihill, Lung Cancer Support Nurse, Lung Foundation Australia; Caitriona Nienaber, 13 11 20 Consultant, Cancer Council WA; A/Prof Nick Pavlakis, President, Australasian Lung Cancer Trials Group, President Elect, Clinical Oncology Society of Australia, and Senior Staff Specialist, Department of Medical Oncology, Royal North Shore Hospital, NSW. We also thank the health professionals, consumers and editorial teams who have worked on previous editions of this title.
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