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Published on July 15th, 2024
Authored by Pfizer Medical Team
Lung cancer is one of the most common types of cancer in Australia.1 Learn about symptoms of lung cancer and how to prevent, recognise, and treat this disease.
Lung cancer happens when cells in the lung grow out of control and form a tumour. Lung cancer always starts in the lung. Typically, it starts in the cells lining the bronchi (the large air passages that lead from the trachea, or windpipe, to the lungs), the bronchioles (small branches of air tubes in the lungs), or alveoli (small air sacs where the lungs and the blood exchange oxygen).2,3
Cancers that begin in another part of the body and then spread to the lungs are usually named after where they have started and will often be referred to as having metastasised to the lungs. 2
Worldwide, lung cancer is the top cause of cancer deaths and the second most diagnosed cancer.4 In Australia, there were around 14,800 new cases and the disease caused around 8,700 deaths in 2023, making it the most common cause of cancer-related deaths in Australia.1 Since 2000, the number of new annual lung cancer diagnoses in Australia have remained fairly consistent, with 58 cases per 100,000 people in 2000 and an estimated 56 cases per 100,000 people in 2023.1 However, there is a noticeable difference between genders. In Australian men, there has been a decrease from 85 cases per 100,000 in 2000 to an estimated 62 cases in 2023.1 On the other hand, there has been an increase in Australian women from 36 cases per 100,000 in 2000 to an estimated 51 cases in 2023.1
The exact causes of lung cancer aren't known, but many factors can increase your risk. The clearest connection is between cigarette smoking and lung cancer, with about 80% of lung cancer deaths attributable to smoking and others often attributed to second-hand smoke.5 However, lung cancer can also occur in people who have never smoked.5
Worldwide, lung cancer is the top cause of cancer deaths and the second most diagnosed cancer.4 In Australia, there were around 14,800 new cases in 2023.1 In 2023, the disease caused around 8,700 deaths that year, making it the most common cause of cancer-related death in Australia.1 Since 2000, the number of new annual lung diagnoses in Australia have remained fairly consistent, with 58 cases per 100,000 people in 2000 and an estimated 56 cases per 100,000 people in 2023.1 However, there is a noticeable difference between genders. In Australian men, there has been a decrease from 85 cases per 100,000 in 2000 to an estimated 62 cases in 2023.1 On the other hand, there has been an increase in Australian women from 36 cases per 100,000 in 2000 to an estimated 51 cases in 2023.1
Smoking cigarettes is the leading cause of lung cancer, but the disease can occur in people who have never smoked.5
The exact causes of lung cancer aren't known, but many factors can increase your risk. The clearest connection is between smoking and lung cancer, with about 80% of lung cancer deaths attributable to smoking and others often attributed to secondhand smoke. Although lung cancer can occur in people who never smoked, it is uncommon.5
A build-up of genetic changes (changes to your DNA) can lead to lung cancer. This can happen when changes occur in the genes that support cell growth, division, and survival (oncogenes) or in the genes that dictate cell division and death (tumour suppressor genes).5
In non-small cell lung cancer cases, for example, mutations in EGFR or ALK genes often occur non-smokers, while KRAS mutations are associated with smokers and former smokers.6
Patients typically acquire the genetic changes related to lung cancer during life. Experts have documented lifestyle and environmental factors that increase the risk of genetic mutations, like cigarette smoke and air pollution.7 But the root causes of some changes remain unclear.5
Inherited genetic changes—which come from a person’s parents—can increase the risk of lung cancer,5 but many cases of lung cancer are not associated with inherited mutations.7
Some lung cancers are linked to acquired (non-inherited) genetic changes with abnormalities in DNA.7 The causes of these acquired abnormalities are unclear, but they may be associated with certain risk factors or exposure to carcinogens (cancer-causing agents). For example, a mutation in the KRAS gene is present in about 20% to 25% of non–small cell lung cancers (NSCLCs). This gene change enables the cancer cells to grow and spread and can affect the disease and treatment options. Approximately 5% of NSCLCs have a change in the ALK gene, which is more often seen in non-smokers and light smokers. Other examples include NSCLCs that have a rearrangement in the ROS1 gene, seen in 1% to 2% of cases, or changes in the BRAF gene, detected in about 5% of cases.6
Not everyone who develops lung cancer smokes, and not everyone who smokes develops lung cancer. Lung cancer in non-smokers and smokers may result from a combination of risk factors.5 Other risk factors for NSCLC, in particular, include:8
Not smoking is the best way to reduce your risk of lung cancer. Avoiding second-hand smoke and environmental exposures to carcinogens at work or in the home can also reduce your risk.9
Cancer can spread beyond the original tumour when the tumour sheds cancer cells. These cells enter the bloodstream or lymph nodes, where they can then spread to other parts of the body.10
Cancer is named by the original location of the tumour.10 If lung cancer spreads (metastasises) to another area of the body, it is called metastatic lung cancer or advanced lung cancer.11 If cancer that starts in another part of the body, e.g. the bowel, metastasises to the lungs, it is called metastatic bowel cancer, bowel cancer with lung metastasis, or bowel cancer that has spread to the lung.10
Lung cancer most often spreads to:11
Nearby lymph nodes or other parts of the lung and chest
Brain
Bones
Liver
Adrenal glands
Other types of cancer can also spread to the lungs.10 Cancers that most commonly spread to the lungs include:12
Breast
Colorectal
Head and neck
Kidney
Testicular
Uterine
Lymphoma
The two main types of lung cancer are non-small cell (NSCLC) and small cell (SCLC), with NSCLC being more prevalent than SCLC.3,9
NSCLC is the most common type of lung cancer, accounting for 80% to 85% of all lung cancer cases.3,9 The two main subtypes of NSCLC are:
Adenocarcinoma. The most common subtype, adenocarcinoma forms in the cells that line the outer layers of the lungs, which are responsible for making mucus.9,13 It is more likely to be caught early before it has spread.3
Squamous cell carcinoma. Another common subtype,13 squamous cell carcinoma starts in the flat cells that line the inside airways of the lungs, called squamous cells. This kind of lung cancer is more likely to be associated with smoking.3
SCLC affects about 10% to 15% of people with lung cancer.3,9 This cancer usually begins in the middle of the lungs, in the nerve cells or hormone-producing cells of the lungs. SCLC tends to spread quickly; for many people, the cancer cells have already spread beyond the lungs by the time they are diagnosed.9,14
In some cases, early-stage lung cancer doesn't cause any symptoms, and people don't start to have noticeable symptoms of lung cancer until it has spread.15
Signs to watch for include:15
Lung cancer can spread. Signs of metastasis can depend on where in the body the cancer has spread and may include:15
Cancer can spread beyond the original tumour when the tumour sheds cancer cells. These cells enter the bloodstream or lymph nodes, where they can then spread to other parts of the body.10
Cancer is named by the original location of the tumour.10 If Lung Cancer spreads to another area of the body, it is called metastatic lung cancer or advanced lung cancer.11 If cancer that starts in another part of the body, say breast, metastasise (spread) to the lungs, it is called “metastatic Breast Cancer to the lungs”.10
Lung cancer most often spreads to:11
Other types of cancer can also spread to the lungs. Those cancers are still named after the original site of the tumour. For example, breast cancer that spreads to the lungs is called metastatic breast cancer.10 Cancers that most commonly spread to the lungs include:12
Cancer can spread beyond the original tumour when the tumour sheds cancer cells. These cells enter the bloodstream or lymph nodes, where they can then spread to other parts of the body.10
Cancer is named by the original location of the tumour.10 If Lung Cancer spreads to another area of the body, it is called metastatic lung cancer or advanced lung cancer.11 If cancer that starts in another part of the body, say breast, metastasise (spread) to the lungs, it is called “metastatic Breast Cancer to the lungs”.10
Lung cancer most often spreads to:11
Other types of cancer can also spread to the lungs. Those cancers are still named after the original site of the tumour. For example, breast cancer that spreads to the lungs is called metastatic breast cancer.10 Cancers that most commonly spread to the lungs include:12
Lung cancer can sometimes lead to collections of symptoms considered syndromes, including:15
Most often associated with NSCLC, Horner syndrome—also called Pancoast tumours—causes eyelid droop, pupil constriction, and other facial symptoms. These are caused by the tumours' effects on the nerves around the eyes and face.
Sometimes, tumours can put pressure on a major vein that carries blood to the heart. This causes swelling in the face, neck, arms, or chest. You may also feel dizzy or have headaches.
These syndromes are most often associated with SCLC but can occur with any type of lung cancer. Paraneoplastic syndromes occur when hormone-like substances produced by the cancer cells enter the bloodstream. Although the cancer itself hasn't spread, these substances can cause symptoms throughout the body, such as hormone dysfunction, immune system problems, and blood clots. The symptoms from these syndromes are sometimes the first signs of lung cancer, but they aren't always suspected as lung cancer.
The types and number of lung cancer symptoms are similar at diagnosis for all sexes.16 However, the incidence of some lung cancers varies. People assigned female at birth tend to have higher rates of adenocarcinoma and lower rates of squamous cell carcinoma than people assigned male at birth. This may be due to differences between the groups in smoking habits.17
Screening tests are designed to find illness before symptoms arise. People with lung cancer have a better chance of being treated successfully when the cancer is caught in earlier stages.18
There are currently no screening programs running in Australia.9 However, in 2023 it was announced that a National Lung Cancer Screening Program will start in July 2025.18 This program will target high-risk individuals for detection of lung cancer in its early stages.18
Although lung cancer is the fifth most common cancer in Australia,1 it can be difficult to diagnose. It is often diagnosed late because symptoms can be vague or there may be no symptoms experienced in the early stages of the disease. When investigating whether you have cancer, your doctor will perform a physical exam and ask about your history.6
A number of tests may be performed, including different imaging tests that can help doctors look for cancer, track its spread, and evaluate a treatment’s progress. A doctor will decide which tests are most appropriate, but some lung cancer tests include:6
To diagnose lung cancer, doctors collect a tissue sample for evaluation.6 This can be done in several ways:
A doctor may also perform blood tests, tests to see how well your lungs work, and tests to see whether the cancer has spread to the other areas of the chest.6,19
In biomarker testing, particularly for NSCLC, the doctor performs molecular testing of cell or tissue samples to look for abnormalities in DNA or levels of specific proteins such as PD-L1. Finding certain changes in the cancer cells helps guide treatment decisions. It also gives doctors a better understanding of the genetic drivers of the disease and can guide treatment options.20
Lung cancer staging is based on the size and location of the tumour and whether the cancer cells have spread beyond the lungs. Based on test results and imaging, your doctor will determine the extent of disease that correlates to a stage.21
For NSCLC, stages range from stage 0 to stage 4 lung cancer. Higher stages correspond with more extensive disease. The stages of lung cancer are:21
Stage 0 lung cancer. The tumour hasn't grown into lung tissue or spread outside the lung.
Stage 1 lung cancer. A small tumour hasn't spread to nearby lymph nodes.
Stage 2 lung cancer. A larger tumour hasn't spread or a smaller tumour has spread to lymph nodes in the lung.
Stage 3 lung cancer. A larger tumour has spread to nearby lymph nodes but not to other parts of the body.
Stage 4 lung cancer. The cancer has spread within the chest or to one or more places outside of the chest.
Doctors tend to stage SCLC using two categories:22
Limited stage: The cancer is in one part a patient's chest and potentially treatable with radiation therapy.
Extensive stage: The cancer has spread to the other areas of a patient’s body.
People diagnosed with lung cancer have a wide range of treatment options available.9,23,24
NSCLC and SCLC have different treatment approaches. Many specialists—including surgeons, oncologists, radiologists, and other healthcare professionals—work together to treat and manage the disease.23,24
A treatment plan considers the type, stage, and location of the cancer, along with results of biomarker testing, side effects, individual preferences, and your overall health and ability to tolerate treatment.9 A treatment plan may include a combination of different therapies.23,24
Surgery aims to remove the tumour completely. It also usually involves removing some lymph nodes in the chest. The surgeon removes some tissue around the tumour for testing to ensure no cancer cells have spread beyond the tumour.23
Surgery is not often used to treat SCLC and is usually reserved for a few cases of limited stage cancer.24 But it has helped treat many patients with stage I and II NSCLC.23 The different types of surgical procedures, particularly for NSCLC, include:9,23
Surgery for lung cancer carries risks similar to any major surgery, including blood clots, infection, and bleeding. Pneumonia is also possible. It can take weeks or months to recover from surgery, depending on the complexity of your procedure.25
Chemotherapy involves intravenous or oral cancer-fighting medications. For NSCLC, chemotherapy can be used before and after surgery, and it’s sometimes used to treat cancer that has spread beyond the lungs.26 It's the most common treatment for SCLC.24
Patients can receive a combination of drugs that work for their specific cancer type. But chemotherapy drugs may kill healthy cells along with cancer cells and have the potential for a range of side effects. Common side effects include fatigue, loss of appetite, hair loss, nausea, vomiting, mouth sores, and higher risk for infection.23,24
Radiation therapy (also known as radiotherapy) is commonly used for NSCLC and uses high-energy X-rays or other particles to kill cancer cells.9 It may be the primary treatment for people who can't undergo surgery. It may also be used before surgery to shrink a tumour, or after surgery to kill any remaining cancer cells.27 In SCLC, it may be used to prevent the spread of cancer cells to other parts of the body, especially the brain.24
This kind of therapy can cause skin irritation, nausea, vomiting, loss of appetite, and sometimes, hair loss where the radiation beam contacts the skin. Most side effects go away when treatment stops.27
Immunotherapy is a growing area of treatment for lung cancer that uses the body's own immune system to fight cancer. These treatments target certain immune system pathways to help the immune system slow or stop the growth of cancer cells.23,24
Immunotherapies are available to treat NSCLC and SCLC either alone or in combination with other therapies, including chemotherapy. The choice of treatment depends on many factors, including your type of cancer, stage, and health.23,24
These treatments are associated with side effects, such as fatigue, nausea, itching, and diarrhea. Other side effects related to the medication's effects on the immune system are possible.28,29
Targeted therapies are medications that work to directly target genetic mutations, proteins, or other molecular aspects of the tumour that cause the cancer to grow. These therapies are chosen based on biomarker or molecular testing of tumour samples to understand the characteristics of the cancer.23 Targeted therapies currently available for NSCLC include:30
Learn more about different types of cancer treatments here.
Getting a cancer diagnosis brings about a lot of emotions.31
Each type of treatment has a different recovery journey, and some have long-term side effects.31
Maintaining a healthy lifestyle, with moderate physical activity and healthy foods, can help overall health. If you haven't quit smoking, quitting now may still benefit you.31
You may consider support from family, friends, and professionals or support groups. Many resources are available to answer questions or connect you to supportive care.31
When sharing your diagnosis with others, especially children, having resources to share can help the conversation.
The outlook and rates of survival for patients with lung cancer vary by stage, type of cancer, and molecular characteristics of the cancer, as well as by patient age and overall health, along with many other factors.2
In Australia, the five-year relative survival rate for lung cancer was 24% between 2015 and 2019.1 This means that, on average, people diagnosed with lung cancer in Australia had a 24% chance of surviving for at lest five years following their diagnosis.1
While overall survival rates for lung cancer remain low, the five-year survival rate has improved over time.1 Newer treatment options are being continuously developed to improve the approach to lung cancer treatment and the outcomes for patients with lung cancer.
The overall five-year relative survival rate for Australians diagnosed with lung cancer in 2015-2019 was 24%.1 This means that, on average, people diagnosed with lung cancer in Australia had a 24% chance of surviving for at least five years following their diagnosis.1 Newer treatment options are being continuously developed to improve the approach to lung cancer treatment and outcomes for patients with lung cancer. Survival varies by type of disease, the molecular characteristics of the disease, age, overall health, and other factors.2
Cigarette smoking is the main risk factor for lung cancer. In Australia, around 90% of lung cancer cases in males and around 65% in females are estimated to result from smoking.32 Smoking can also cause 15 other cancer types. People who currently smoke are estimated to die an average of 10 years earlier than non-smokers.32 As soon as you quit smoking, your long-term health benefits improve and you will reduce your risk of dying prematurely.32
People diagnosed with lung cancer have a wide range of treatment options available.9,23,24 Many specialists, including surgeons, oncologists and other healthcare professionals work together to treat and manage the disease.23,24 A treatment plan for lung cancer considers many factors, including the type, stage and location of the cancer.23,24
For most people, particularly those with more advanced stages of cancer, current treatments may not cure NSCLC30 or SCLC33, but are designed to manage the disease and improve quality of life. In some cases of early-stage NSCLC, surgery may effectively offer a cure.23
People with a family history of lung cancer tend to be at slightly higher risk for developing the disease, but most lung cancers are not caused by inherited genetic changes and may be based on certain shared risk factors.7
Some lung cancers have acquired genetic changes with certain abnormalities in DNA that are acquired and not inherited.5 The cause of these acquired abnormalities are unclear and may be associated with certain risk factors. For example, a mutation in the KRAS gene is present in about 20% to 25% of non–small cell lung cancers (NSCLCs). This gene change enables the cancer cells to grow and spread. These gene changes have been found to affect the disease and treatment options.6
About 5% of NSCLCs have a change in the ALK gene, which is more often seen in non-smokers and light smokers. Other examples include NSCLCs that have a rearrangement in the ROS1 gene, seen in 1% to 2% of cases, or changes in the BRAF gene, detected in about 5% of cases.6