What is lung cancer?
Lung cancer starts when abnormal cells grow out of control in the lung. They can invade nearby tissues and form tumours. Lung cancer can start anywhere in the lungs and affect any part of the respiratory system.
The cancer cells can spread, or metastasize, to the lymph nodes and other parts of the body.
Lung cancers are divided into small cell lung cancers (SCLC) and non-small cell lung cancers (NSCLC). Small cell lung cancers usually grow more quickly and are more likely to spread than non-small cell lung cancer.
Lung cancer is the leading cause of cancer deaths in the world.footnote 1
What causes lung cancer?
Most lung cancer is caused by smoking. But sometimes lung cancer develops in people who have never smoked.
Being exposed to second-hand smoke, arsenic, asbestos, radioactive dust, or radon can increase your chances of getting lung cancer. People who are exposed to radiation at work or elsewhere have a higher chance of getting lung cancer.
What are the symptoms?
The first signs of lung cancer may include:
- Feeling short of breath.
- Chest pain.
- Having blood in any mucus that you cough up.
Because these symptoms are so general, many people don't suspect lung cancer. And by the time they see a doctor, often the cancer has already started to spread.
If the cancer spreads within and beyond the chest, other symptoms may occur.
How is lung cancer diagnosed?
Your symptoms and your medical history—especially if you have any history of cancer in your family—will help your doctor decide how likely it is that you have lung cancer and whether you need tests to be sure.
Lung cancer is usually first found on a chest X-ray or a CT scan. More tests are done to find out what kind of cancer cells you have and whether they have spread beyond your lung. These tests help your doctor and you find out what stage the cancer is in. The stage is a rating to measure how big the cancer is and how far it has spread.
How is it treated?
Finding out that you have cancer can change your life. You may feel like your world has turned upside down and you have lost all control. Talking with family, friends, or a counsellor can really help. Ask your doctor about support groups. Or call the Canadian Cancer Society (1-888-939-3333) or visit its website at www.cancer.ca.
Can you prevent lung cancer?
Lung cancer that is caused by smoking can be prevented. So it is important to stop smoking—or to stop being around someone else's smoke.
Even if you have smoked a long time, quitting can lower your chances of getting cancer. If you already have lung cancer, quitting makes your treatment work better and can help you live longer.
Health Tools help you make wise health decisions or take action to improve your health.
More than 8 out of 10 lung cancers are caused by smoking.footnote 3 Tobacco smoke contains carcinogens—substances that cause cancer. These substances damage lung cells, and over time the damaged cells can turn into lung cancer.
The more you smoke and the longer you have smoked, the higher your chances of getting lung cancer. You lower your chances when you quit or cut down on how much you smoke.
A few people get lung cancer after being exposed to other harmful substances, including asbestos, radioactive dust, radon, or radiation such as X-rays.
Cancer also may be caused by gene changes (mutations) that occur as you get older.
Symptoms of lung cancer may include:
Coughing symptoms, such as:
- A new cough or a cough that doesn't go away.
- In smokers who have a chronic cough, a change in how severe their cough is or how much they cough.
- Coughing up blood or bloody mucus.
Chest symptoms, such as:
- Chest, shoulder, or back pain that doesn't go away and often gets worse with deep breathing.
- New wheezing.
- Shortness of breath.
General symptoms, such as:
- Swelling in the neck and face.
- Difficulty swallowing.
- Weight loss and loss of appetite.
- Increasing fatigue and weakness.
- Recurring respiratory infections, such as pneumonia.
When lung cancer spreads, there may be other symptoms. For example, if it spreads to the spine or bones, it may cause pain in the back or other bones or cause weakness in the arms or legs. If it spreads to the brain, it may cause seizures, headaches, or vision changes.
Lung cancer can start anywhere in the lungs and may affect any part of the respiratory system. This can cause breathing or heart problems, such as:
- Pleural effusion, which is the buildup of fluid between the outer lining of the lungs and the chest wall. This is a common condition with lung cancer.
- Coughing up large amounts of bloody sputum.
- Collapse of a lung (pneumothorax).
- Blockage of the airway (bronchial obstruction).
- Recurrent infections, such as pneumonia.
- Pericardial effusion, which is the buildup of fluid in the space between the heart and the sac around the heart (pericardium). This condition is not common with lung cancer.
As lung cancer grows, it may spread (metastasize) to other parts of the body. Lung cancer is classified in stages, which describe how far the cancer has grown and spread.
The long-term outcome (prognosis) for lung cancer depends on how much the cancer has grown and spread.
What Increases Your Risk
A risk factor for lung cancer is something that increases your chance of getting this cancer. Having one or more of these risk factors can make it more likely that you will get lung cancer. But it doesn't mean that you will definitely get it. And many people who get lung cancer don't have any of these risk factors.
About 85 out of 100 lung cancers are related to cigarette smoking.footnote 4 Smoking cigars or a pipe may also increase your risk for lung cancer.
Your risk of getting lung cancer increases:
- The longer you smoke.
- The more cigarettes you smoke each day.
Quitting smoking lowers your risk for getting cancer, and your risk keeps going down as long as you don't smoke. Even cutting down how much you smoke may reduce your risk (but not as much as quitting completely).
If you live with a smoker, you have a higher risk for lung cancer compared with a person who lives in a non-smoking environment.
For more information, see the topic Quitting Smoking.
Exposure to some substances may increase your risk for lung cancer, including:
- Cannabis (marijuana). Smoking one cannabis cigarette, or a joint, may affect the lungs as much as smoking a pack of cigarettes.footnote 5
- Certain chemicals. These include arsenic and asbestos.
- Radiation. This includes exposure from your work place, medical tests, or from the environment (such as radioactive dust).
- Radon gas. This includes exposure from your home or work place.
- Air pollution. Living where the air is very polluted can increase your risk for lung cancer.
Some gene changes (mutations) can increase the risk of getting lung cancer. These gene changes mostly occur as a person gets older.
When should you call your doctor?
Call 911 or other emergency services immediately if you:
- Have new or sudden onset of chest pain that is crushing or squeezing, is increasing in intensity, or occurs with any other symptoms of a heart attack, such as shortness of breath and nausea.
- Have new or sudden difficulty breathing.
- Are coughing up a lot of blood (not just streaks of blood or a small amount of blood mixed with a lot of mucus) from your lungs.
- Have been vomiting and feel that you may pass out when you sit up or stand.
Call your doctor immediately if you have:
- Laboured, shallow, rapid breathing with shortness of breath or wheezing, even when you are resting.
- Swelling of your neck and face.
Call your doctor to find out when an evaluation is needed if you:
- Have new chest pain (more than just discomfort when you cough) that lasts a long time and gets worse when you breathe deeply.
- Develop symptoms of pneumonia, such as shortness of breath, cough, and fever.
- Have a cough that produces a small amount of bloody (bright red or rust-coloured) mucus.
- Frequently cough up yellow or green mucus from your lungs (not post-nasal drainage) for longer than 2 days.
- Vomit frequently from coughing.
- Have a cough that lasts longer than 4 weeks.
- Breathe normally when you are at rest but are very short of breath after any physical exercise.
- Have increasing fatigue for no apparent reason.
- Have unexplained weight loss.
Who to see
Health professionals who can evaluate and treat your lung cancer include:
Examinations and Tests
Your doctor will first do a physical examination and ask about your medical history to find out your risk for lung cancer and look for any lung problems. The examination may include a chest X-ray and blood test.
If your examination suggests that you may have lung cancer, your doctor may recommend other tests, such as:
- A PET scan, a CT scan, or a PET-CT scan.
- Tissue sampling. Doctors can use a variety of tests to examine tissue or fluid samples under a microscope and look for cancer cells. Tests include:
Tests after diagnosis
After lung cancer has been diagnosed, testing is done to find out whether the cancer has spread (metastasized) to other organs in your body and to determine the stage of the cancer.
- MRI of the brain, spine, or chest.
- CT scan of the brain, neck, chest, abdomen, or pelvis.
- PET scan.
- Bone scan.
- Endoscopic ultrasound (EUS). In this test, a small ultrasound probe at the end of the endoscope is placed down the throat to the chest area. The ultrasound can help find cancer behind the breast bone or in lymph nodes in the area. EUS may also be used to guide a biopsy of the lymph nodes, the lung, or other areas.
- Bone marrow aspiration and biopsy.
If you have non-small cell lung cancer, your doctor may check for tumour markers (biomarkers) that are caused by gene changes (mutations) in cancer cells. This can help your doctor choose the treatment that will work best for you.
Tests before surgery
A person whose lungs aren't working well may not be a good candidate for surgery. If surgery to remove cancer in all or part of a lung is being considered, the following tests may be done:
Screening tests help your doctor look for a certain disease or condition before you have any symptoms. This can increase your chances of finding the problem early, when it's more treatable.
Studies haven't yet shown that routine screening for lung cancer saves lives or prevents lung cancer. But it may help those who have the highest risk for lung cancer—people 55 and older who are or were heavy smokers. Talk to your doctor about the pros and cons of lung cancer screening.
Treatment for both non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC) may include the following:
- Surgery. This may involve removing the cancer, the affected lobe of lung, or the entire lung.
- Radiation. Radiation is often used in combination with surgery or chemotherapy or both. For more information, see Other Treatment.
- Chemotherapy. Chemotherapy can help control the growth and spread of the cancer, but it is a cure in only a small number of people. For more information, see Medications.
- Laser therapy. Laser therapy uses a highly focused beam of light to kill cancer cells.
Other treatments for NSCLC include:
- Targeted therapy. Targeted therapy is the use of medicines such as tyrosine kinase inhibitors or monoclonal antibodies to block cancer growth.
- Photodynamic therapy (PDT). PDT uses medicine and a special light to treat cancer.
- Cryosurgery. Cryosurgery may be used to freeze and destroy lung tumours.
- Electrocautery. Electrocautery is the use of a low-voltage electrical charge to destroy tumours.
- Watchful waiting. Watchful waiting means being watched closely by your doctor but not having treatment until you show symptoms or a change of some kind. It is only used in rare cases.
Your doctor may check for tumour markers (biomarkers), such as EGFR, ALK, and KRAS, that are caused by gene changes (mutations) in cancer cells. This can help your doctor choose the treatment that will work best for you.
Other treatments for SCLC include:
- Endoscopic stent placement. This is done to open a blocked airway so you can breathe more easily. A flexible lighted viewing instrument (endoscope) is used to place a small hollow tube (a stent) in your bronchial tubes if a tumour is making it hard for you to breathe.
The kind of treatment and the long-term outcome of lung cancer depends on the type and stage of the cancer and also on your age and your overall health.
Some treatments can cause side effects. Home treatment measures may help.
Your quality of life is critical when you are considering your treatment choices. Discuss your personal preferences with your oncologist when he or she recommends treatment.
You can find more information about lung cancer online at the:
- Canadian Cancer Society website at www.cancer.ca.
- U.S. National Cancer Institute website at www.cancer.gov.
Dealing with your emotions
If you have been recently diagnosed with lung cancer, you may feel denial, anger, and grief. Reactions vary from person to person. Talk to your doctor about steps you can take to help with your emotional reactions.
If you are having a hard time moving forward with your life, talk with your doctor. Your cancer treatment centre may offer counselling services. You may also contact your local chapter of the Canadian Cancer Society to help you find a support group.
Having cancer can change your life in many ways. For support in managing these changes, see the topic Getting Support When You Have Cancer.
After initial treatment for lung cancer, it is important to receive follow-up care.
- Your oncologist will schedule regular checkups, usually every 3 to 4 months, depending on the therapies used in initial treatment. After 2 to 3 years, regular checkups will occur less often but more than just once a year, depending on your medical history.
- Checkups may include a physical examination, blood tests, chest X-rays, CT scans, or other laboratory tests recommended by your oncologist.
You may be interested in participating in research studies called clinical trials. Clinical trials are based on the most up-to-date information and are designed to find better ways to treat people who have cancer.
People who do not want standard treatments or are not cured by standard treatments may want to participate in clinical trials. These are ongoing in most parts of Canada and in some other countries around the world for all stages of lung cancer.
Hospice palliative care
Cancer treatment has two main goals: curing cancer and making your quality of life as good as possible. Hospice palliative care can improve your quality of life by helping you manage your symptoms. It also can help you with other concerns that you may have when you're living with a serious illness.
For some people who have advanced cancer, a time comes when treatment to cure cancer no longer seems like a good choice. This can be because the side effects, time, and emotional stress related to treatment are greater than the promise of cure or relief. But this isn't the end of treatment. Hospice palliative care providers will work to help manage pain and other symptoms or side effects. They may help you decide what treatment you want or don't want. And they can help your loved ones understand how to support you.
One study of people with non-small cell lung cancer who started hospice palliative care when they were diagnosed with lung cancer found that they not only felt better but also lived a little longer than the people who didn't have hospice palliative care.footnote 6
It can be hard to decide when to stop treatment to prolong your life and shift the focus to end-of-life care. You and your doctor can decide when you may be ready for hospice palliative care.
Most lung cancers are caused by smoking. If you use tobacco, you can help prevent lung cancer by quitting. For more information, see the topic Quitting Smoking.
Other prevention tips
You may be able to make other changes in your life that can help prevent lung cancer:
During treatment for any stage of lung cancer, there are steps you can take at home to manage some symptoms and side effects. Be sure to follow any instructions your doctor has given you.
- Home treatment for nausea or vomiting includes watching for and treating early signs of dehydration, such as a dry mouth, sticky saliva, and reduced urine output.
- Home treatment for diarrhea includes resting your stomach and being alert for signs of dehydration.
- Home treatment for constipation includes gentle exercise along with adequate intake of fluids and a diet that is high in fruits, vegetables, and fibre.
- Home treatment for fatigue includes making sure you get extra rest while you are receiving chemotherapy or radiation.
- Home treatment for pain includes heat and cold packs and learning how to distract yourself from the pain.
- Home treatment for a sore mouth includes avoiding certain foods and rinsing with mouthwash or an antacid.
- Home treatment for sleep problems includes having a regular bedtime and avoiding caffeine late in the day.
Other issues you may be able to handle at home include:
- Loss of appetite or difficulty eating. Eating several small meals throughout the day or eating soft, bland foods may help if you do not have an appetite or if certain foods are difficult to eat.
- Coughing. You may have an ongoing cough or develop a severe cough. Your doctor can recommend some non-prescription cough medicines or prescribe some medicines to help relieve your symptoms.
If you smoke and have lung cancer, quitting smoking will make your treatment more effective and may help you live longer. Smoking delays healing after surgery, so you may have a better recovery from lung cancer surgery if you have quit smoking.
People with early-stage lung cancer who continue to smoke during radiation therapy have been shown to have shorter survival times than those who do not smoke.footnote 7
Smoking may also make chemotherapy less effective. The nicotine in tobacco seems to help the cancer cells and their blood supply multiply while also protecting the cancer cells from destruction.footnote 8
For information and help quitting smoking, see the topic Quitting Smoking.
Medicines for lung cancer mainly involve chemotherapy. Other medicines may be used to help with pain.
Chemotherapy is the most effective treatment for small cell lung cancer. It can help control the growth and spread of the cancer, but it cures lung cancer in only a small number of people. It also may be used to treat more advanced stages of non-small cell lung cancer.
Chemotherapy is called a systemic treatment because the medicines enter your bloodstream, travel through your body, and kill cancer cells both inside and outside the lung area. Some chemotherapy drugs are taken by mouth (orally), while others are injected into a vein (intravenous, or IV).
Chemotherapy medicines used for lung cancer may include carboplatin, cisplatin, or paclitaxel.
Most chemotherapy causes some side effects. Your doctor may prescribe medicines to control nausea or vomiting.
You may be concerned about losing your hair from cancer treatment. Not all chemotherapy medicines cause hair loss, and some people have only mild thinning that is noticeable only to them. Talk to your doctor about whether hair loss is an expected side effect of the medicines you will receive.
Chemotherapy may be combined with surgery. It may be given before or after surgery to kill cancer cells.
Medicines for pain
Pain is one of the main concerns of people who have cancer. But cancer pain can almost always be controlled with medicines and other options. Medicines used for cancer pain include prescribed medicines, such as hydromorphone or morphine, or non-prescription medicines, such as aspirin and similar drugs.
Lung surgery to remove the cancer may be an option when your cancer is in only one lung or present in one lung and in nearby lymph nodes. It usually is done only if your doctor thinks all the cancer can be removed and your general health is good enough for you to handle the surgery.
Nearby lymph nodes may also be removed to find out whether the cancer has spread.
The type of surgery performed depends on the location and size of your lung cancer:
- Wedge resection. The surgeon removes a small wedge-shaped piece of lung that contains the lung cancer and a margin of healthy tissue around the cancer.
- Lobectomy (say "low-BEK-tuh-mee"). The right lung has three lobes and the left lung has two lobes. A lobectomy removes the entire lobe of your lung that contains the cancer. Your lungs can function with the lobes that remain.
- Pneumonectomy (say "new-muh-NEK-tuh-mee"). A pneumonectomy removes your entire lung that contains the lung cancer.
- Sleeve resection. The surgeon removes part of the bronchus, the hollow tube at the end of the trachea (windpipe) that spreads into each lung like a tree.
The side effects from surgery will depend on the type of surgery that you have. There is less pain with surgery that is minimally invasive (VATS) than the traditional surgery (thoracotomy). You may have numbness and tingling in the chest area. This usually goes away in a few weeks or months.
Radiation treatment is the use of high-energy X-rays to kill cancer cells and shrink tumours. Most radiation for lung cancer is given externally, which means that the radiation comes from a machine outside the body.
Radiation is often used in combination with surgery or chemotherapy or both. But it may be used alone if surgery is not possible.
People who can't have surgery may have a special type of radiation called stereotactic radiosurgery (SRS). This isn't surgery but a series of very high doses of radiation that are aimed at the cancer. SRS is usually given to treat tumours that have spread to the brain. SRS may also be called gamma knife radiosurgery, cyberknife, stereotactic ablative radiotherapy (SABR), or stereotactic body radiotherapy (SBRT).
Radiation may be used to prevent small cell lung cancer from growing in your brain. This is called prophylactic cranial irradiation (PCI).
Radiation also may be used as part of hospice palliative care to:
- Shrink tumours that make it hard for you to swallow.
- Reduce tumours that block your airway and make it hard for you to breathe.
- Relieve pain from cancer that has spread to your bones or spinal cord.
Radiation may cause side effects, such as skin changes, fatigue, and trouble swallowing.
Other medical treatments
- Targeted therapy with monoclonal antibodies and tyrosine kinase inhibitors may be used to treat NSCLC. Monoclonal antibodies, such as bevacizumab and cetuximab, can kill cancer cells, block their growth, and keep cancer from spreading. Tyrosine kinase inhibitors, such as erlotinib and gefitinib, can stop tumours from growing by blocking signals inside cancer cells.
- Laser therapy uses a narrow beam of very intense light to destroy cancer cells. This treatment may be used to remove tumours that block the airway.
- Photodynamic therapy uses laser light to kill cancer cells. It's used as palliative treatment to destroy tumours that block the airway.
- Electrocautery uses a probe or needle to burn (cauterize) abnormal tissue or tumours.
- Cryosurgery (also called cryoablation) freezes the tumour and kills it.
- Radiofrequency ablation uses a small needle inserted through the skin and into the tumour. Energy passes through the needle into the tumour. This heats and kills cancer cells. It also closes up the little blood vessels in the area so there is less bleeding.
- Stents—small, wire-mesh tubes—may be inserted into a blocked airway and expanded to hold the airway open.
- Watchful waiting means that you are being watched closely by your doctor but not having treatment until you show symptoms or a change of some kind.
People sometimes use complementary treatments along with medical treatment to help relieve symptoms and side effects of cancer treatments. Some of the complementary therapies that may be helpful include:
- Acupuncture to relieve pain.
- Meditation or yoga to relieve stress.
- Light massage (not deep tissue or intense pressure) or biofeedback to ease tension.
- Breathing exercises for relaxation.
These mind-body treatments may help you feel better. They can make it easier to cope with treatment. They also may reduce chronic low back pain, joint pain, headaches, and pain from treatments.
Before you try a complementary therapy, talk to your doctor about the possible value and potential side effects. Let your doctor know if you are already using any such therapies. They are not meant to take the place of standard medical treatment.
- Silverstri GA, Jett JR (2010). Clinical aspects of lung cancer. In R Mason et al., eds., Murray and Nadel's Textbook of Respiratory Medicine, 5th ed., vol. 2, pp. 1116–1144. Philadelphia: Saunders.
- American Cancer Society (2012). Cancer Facts and Figures 2012. Atlanta: American Cancer Society. Available online: http://www.cancer.org/Research/CancerFactsFigures/CancerFactsFigures/cancer-facts-figures-2012.
- Khuri FR (2016). Lung cancer and other pulmonary neoplasms. In L Goldman, A Shafer, eds., Goldman-Cecil Medicine, 25th ed., vol. 2, pp. 1303–1313. Philadelphia: Saunders.
- U.S. Department of Health and Human Services (2010). A Report of the Surgeon General: How Tobacco Smoke Causes Disease—The Biology and Behavioral Basis for Smoking-Attributable Disease Fact Sheet. Available online: http://www.surgeongeneral.gov/library/tobaccosmoke/factsheet.html.
- Aldington S, et al. (2008). Cannabis use and risk of lung cancer: A case-control study. European Respiratory Journal, 31(2): 280–286.
- Temel JS, et al. (2010). Early palliative care for patients with metastatic non–small-cell lung cancer. New England Journal of Medicine, 363(8): 733–742.
- Fox JL, et al. (2004). The effect of smoking status on survival following radiation therapy for non–small cell lung cancer. Lung Cancer, 44(3): 287–293.
- Dasgupta P, et al. (2006). Nicotine inhibits apoptosis induced by chemotherapeutic drugs by up-regulating XIAP and survivin. Proceedings of the National Academy of Sciences, 103(16): 6332–6337.
Other Works Consulted
- National Cancer Institute (2011). Small Cell Lung Cancer PDQ: Treatment—Patient Version. Available online: http://www.cancer.gov/cancertopics/pdq/treatment/small-cell-lung/Patient.
- National Cancer Institute (2012). Non-Small Cell Lung Cancer PDQ: Treatment—Patient Version. Available online: http://www.cancer.gov/cancertopics/pdq/treatment/non-small-cell-lung/Patient.
- National Cancer Institute (2012). Small Cell Lung Cancer PDQ: Treatment—Health Professional Version. Available online: http://www.cancer.gov/cancertopics/pdq/treatment/small-cell-lung/healthprofessional.
- Neville A (2009). Lung cancer, search date May 2008. Online version of BMJ Clinical Evidence: http://www.clinicalevidence.com.
Current as of: August 22, 2019
Author: Healthwise Staff
E. Gregory Thompson MD - Internal Medicine
Brian D. O'Brien MD - Internal Medicine
Adam Husney MD - Family Medicine
Kathleen Romito MD - Family Medicine
Michael Seth Rabin MD - Medical Oncology
Current as of: August 22, 2019