Lung Cancer

Lung cancer is a growth of abnormal cells inside the lungs. The cells divide and grow faster than healthy cells, forming into clusters called tumours. The cancer cells replace and destroy the healthy tissue around them. Lung cancer can also spread (metastasize) to other parts of the body. 

Nearly 30,000 Canadians will be diagnosed with lung cancer this year, and they need our help. Our goal? Giving them a fighting chance by eliminating the barrier of stigma. 

Anti Stigma purple

Look for the Stigma Spotlight in each section of this content. It will help you learn how stigma affects people with lung cancer – a devastating disease that nobody deserves.

Get help now

If you (or a loved one) have been diagnosed with lung cancer and need assistance coping, we are here to help. Skip to our Coping with Lung Cancer section, or reach out to our Lung Health Line for free one-on-one guidance from a Certified Respiratory Educator.

The Science of Lung Cancer

Your lungs take in oxygen when you inhale, and release carbon dioxide when you exhale. When learning about lung cancer, it’s helpful to go a little deeper and get to know our lungs at the cellular level.

Like your other organs, your lungs are made of cells. Healthy cells grow and divide over time, and even die. The trouble starts when your cells start to grow uncontrollably. This happens because the DNA inside your cells changes (think aging) or becomes damaged (think smoke, pollution or other things in your environment or lifestyle).  Once cells turn cancerous and continue to quickly divide, tumours form.

Lung cancer can start anywhere in the lungs, from the bronchus (which brings air in) to the pleura (the thin tissue that covers the lungs and lines the chest cavity) and anywhere in between.  

Lung cancer types

Depending on where cancer cells are found and how they’re growing and spreading, lung cancer is put in one of two main categories.
Non-small cell lung cancer (NSCLC)Small cell lung cancer (SCLC)
How common is it?This is the most common type of lung cancer, accounting for around 85% of cases. This type of lung cancer is less common, accounting for around 10 to 15% of cases.
How does it spread?NSCLC usually spreads more slowly than other lung cancers.SCLC is usually more aggressive and can result in larger tumours.
Why’s it called that?“Non-small” doesn’t have anything to do with the size of the tumours or extent of the cancer. It refers to the kind of cells found in the cancer, and how they look under the microscope.“Small” doesn’t have anything to do with the size of the tumours or extent of the cancer. It refers to the kind of cells found in the cancer, and how they look under the microscope – small and round.
Major sub-types- Adenocarcinoma (the most common form of lung cancer in general)
- Squamous cell carcinoma
- Large cell carcinoma
- Small cell carcinoma
- Mixed small cell/large cell
- Combined small cell carcinoma
How it’s stagedStage I, II, III, or IV.Limited Stage, Extensive stage
Treatment optionsChemotherapy, surgery, and radiation therapy are all common treatments for non-small cell lung cancer.
Targeted treatments are an option for some patients. These drugs affect cancer’s ability to grow by targeting specific genes or other factors. To find out if you qualify for any of these treatments, you will need to undergo molecular testing.
Immunotherapy, a kind of treatment that boosts the immune system’s ability to defend against cancer, is an option for some patients. Like targeted treatments, immunotherapies require further testing.
Systemic (whole body) treatments like chemotherapy are more effective in fighting small cell lung cancer than localized treatments like surgery.
Surgery is rare, but may be an option if the cancer has not reached the lymph nodes.
Depending on the stage of the cancer, radiation therapy may be used in combination with chemotherapy (chemoradiation), or could be used to prevent the spread of cancer to the brain.
There are currently no immunotherapy or targeted treatments for SCLC.

There are other types of lung cancer too, though they are less common. They include:

  • Carcinoid (neuroendocrine) tumours, which grow slowly and rarely spread
  • Soft-tissue sarcoma, which grow very slowly, usually in the pleural membranes
  • Pleural mesothelioma, which is rare and usually linked to asbestos exposure

When cancer spreads from the lungs 

Lung cancer can spread (“metastasize”) to other parts of the body. The most common places that lung cancer spreads to include the brain, bones, lymph nodes, adrenal glands, and liver. Cancer can also spread from one lung to the other.
Once lung cancer has spread, it usually isn’t curable. That’s one of the reasons why catching lung cancer early is so important. 

When cancer spreads to the lungs 

Cancer can also start in other parts of the body before being found in the lungs. Cancer that has spread from another part of the body to the lungs isn’t the same as cancer that has started within the lungs (primary lung cancer).  

Early Lung Cancer Symptoms

In its early stages, lung cancer can come with no signs or symptoms at all. That’s why screening is very important for people who are at the highest risk of developing lung cancer. 
The most common early symptoms of lung cancer include:
  • A stubborn cough that won’t go away (which could make it difficult to sleep)
  • Coughing up blood or rust-coloured sputum (phlegm)
  • Laboured breathing, shortness of breath, or wheezing
  • Chest pain (deep in the lungs when lifting, coughing, or laughing)
These symptoms are not unique to lung cancer, but it’s best to get checked out if you experience them. Some could be signs of chronic obstructive pulmonary disease (COPD) or other conditions.

As you begin treatment, the symptoms you experience may happen because of the disease itself, or they could be side effects of your treatment. 

What causes lung cancer? 


The best action you can take to lower your risk of lung cancer is to live a smoke-free life. For those who do not smoke, it’s as simple as avoiding second hand smoke and choosing not to start smoking or vaping.  For those who currently smoke, quitting can be a more complex journey – but we’re here to help. It’s never “too late” to quit smoking, even after a lung cancer diagnosis. 
With or without a history of smoking, we will be here for you. 


Radon is the second leading cause of lung cancer, and the first leading cause of lung cancer in non-smokers.  Radon is a natural radioactive gas that comes from the breakdown of uranium in soil and rock. In enclosed spaces, radon can build to unsafe levels.  Learn more about radon and how to test for it in your home, at Health Canada.

Workplace exposures

Some workers have a higher risk of developing lung cancer. This most often impacts people who work with or around asbestos, diesel engine exhaust, crystalline silica, welding fumes, nickel, chromium, radon and second hand tobacco smoke.


A family history of lung cancer may increase your risk of lung cancer, especially one of your parents, siblings, or children have been diagnosed. 
Lung Cancer Screening

Lung Cancer Screening

“Screening” means checking for cancer before symptoms develop, even if you feel healthy. Screening can help detect cancer in its earliest stages.

Middle aged man hugs his adult son. He looks supported.

Diagnosis and Staging

Being diagnosed with lung cancer is often life-changing, and emotional distress is common. Understanding the steps and procedures can help you feel more in control, prepare you to advocate for yourself during your treatment.

Navigating Your Lung Cancer Care

The cancer care system can seem overwhelming at first, but we’re here to help you navigate it in a way that makes you feel empowered and supported. 

Lung Cancer Screening


Your treatment team will consider a number of factors when choosing treatments that will fight your cancer most effectively. They will consider your overall health, age, and personal situation.

An elderly man comforts his wife

Questions and Answers About Coping with Lung Cancer

The questions we list here are the top coping questions reported by people with lung cancer. Our answers provide some basic information, but we encourage you to discuss any concerns or questions with your oncologist and other members of your cancer care team.