Lung cancer develops when cells become abnormal and grow out of control in one or both of a person’s lungs. It is the world’s most lethal cancer. In healthy lungs, normal lung tissue cells reproduce and develop into healthy lung tissue. With lung cancer, abnormal cells reproduce rapidly and never grow into normal lung tissue. Lumps of cancer cells form tumours which disrupt the functioning of the lung.
Lung cancer often develops slowly. It is thought that cells first become abnormal at least five years before cancer can be detected. The reasons for this delay include:
- Most tumours grow slowly
- The lungs are large
- The lungs do not feel pain (pain is not common in lung cancer)
- Some of the symptoms are similar to those of COPD, which many smokers also have.
The result of this is that by the time lung cancer is diagnosed, it has often spread outside the lung. If this happens, the cancer is not curable.
Lung Cancer Screening
Research in America has shown that screening people who have the highest chance of developing lung cancer can prevent deaths.
Lung cancer screening involves a CT scan of the lungs. Sometimes, more tests are required. The CT scan can find lung cancer before it has spread and treatment with surgery is offered to cure it. Lung cancer screening does not prevent lung cancer but finds it at an earlier stage when there is a better chance of successful treatment.
LungScreen WA is an exciting clinical research initiative led by respiratory physicians Dr Fraser Brims and Dr Annette McWilliams. The program aims to improve and develop ways of finding lung cancer when it is in this early stage. Through their diverse research, the LungScreen WA team collaborates with national and international research colleagues.
Low Dose CT Scan
Natural radiation is all around us, all of the time. Each year we are exposed to about three units of radiation. Too much radiation could cause people harm, so LungScreen WA like to keep any radiation from medical tests as low as possible. A ‘normal’ chest CT scan dose of radiation is about 4 or 5 units, which is OK if you really need to have it. For screening CT scans – people might need a scan every year for many years – in which case this dose could be too high.
Modern technology means that a low dose CT scan dose can be 40 times less than a standard CT scan – this is about the same as having a chest X-ray. A dose as low as this means doctors can safely offer these low dose CT scans and not be worried about the radiation dose. While the images are sometimes not quite as clear as with standard scans, they are definitely good enough to spot an early small lung cancer.
Lung Cancer Programs
The LungScreen WA Pilot Project
Between 2015-2017 LungScreen WA ran a small test project to better understand some of the challenges for screening for early lung cancer using low dose CT. All the scans were performed in community radiology centres (i.e. not in busy hospitals). They also tested different ways of choosing who is at risk of lung cancer (and therefore should get a low dose CT scan), and also a different way of following up repeat CT scans using a protocol to guide decisions.
From nearly 50 people taking part, they found that a telephone-based risk questionnaire worked effectively, they found (and treated) several early lung cancers (meaning the risk-test worked well) and all participants were followed up very well using the protocol. The results of this study will help inform policy making within WA and Australia.
International lung screen trial (ILST)
The ILST is a big international study aiming to recruit more than 4,000 participants, with 2000 coming from Australia, and 500 from Perth. Other centres in Australia are Brisbane (where the study is based), Sydney and Melbourne. The aim of the study is to understand the best way of choosing high-risk people for lung cancer screening and also the best way of following up with repeat CT scans.
There are a number of sub-studies from ILST, including our own in WA examining the best way to recruit people into a lung cancer screening program.
The Asbestos Review Program
The Asbestos Review Program (ARP) is a dedicated clinic to follow up people who have worked with, or who have had significant exposure to, asbestos. The clinic has been running since 1990 and specialises in dealing with asbestos-related lung diseases. The ARP arranges an annual health check-up using specialist breathing tests, blood tests and the latest CT scan technology.
It is known that people who have been exposed to asbestos have a greater chance (but still a small one) of developing cancer of the lung and mesothelioma (cancer of the lining of the lung). At present, the only known actions that can be taken to reduce these risks are to stop smoking and avoid further contact with asbestos. The careful use of a low-dose CT scans of the chest can identify lung cancer at an early stage when it is potentially curable and the ARP offers this test. They also have many years of experience in dealing with other lung diseases that asbestos exposure can cause.