Lung Cancer

Lung cancer is cancer that starts in the lungs. Cancer is a disease where cancer cells grow out of control, taking over normal cells and organs in the body. There are two major types of lung cancer. Each type of lung cancer grows and spreads in different ways. Each type may be treated differently.

Non-small cell lung cancer
This is the most common type of lung cancer. It usually spreads more slowly than other lung cancers. There are three major types of non-small cell lung cancer:

  • Squamous cell carcinoma
  • Adenocarcinoma
  • Large cell carcinoma

Small cell lung cancer
This is a less common type of lung cancer and it spreads faster than non-small-cell lung cancer. Small cell lung cancer is named for the size of cancer cells, which can only be seen under a microscope. There are three major types of small cell lung cancer:

  • Small cell carcinoma
  • ​Mixed small cell/large cell
  • Combined small cell carcinoma

There are also other types of lung cancer.

Who is at risk?
Smoking is the number one risk factor for developing lung cancer. The following factors are known to increase the risk of developing lung cancer:

  • Smoking tobacco
  • Breathing in second-hand smoke
  • Exposure to asbestos or radon
  • Occupational exposure to chemical carcinogens
  • A combination of any of the above risks.

If you smoke and you are exposed to another risk factor (e.g. radon, asbestos) you are at much higher risk for lung cancer.

Signs and symptoms sometimes seen in lung cancer:

  • A cough that doesn't go away and gets worse over time
  • Chest pain that doesn't go away
  • Coughing up blood
  • Feeling short of breath
  • Wheezing
  • Losing your voice (hoarseness)
  • Getting sick with pneumonia and bronchitis a lot
  • Swollen neck and face
  • Not hungry, losing weight without trying
  • Feeling tired

People with these symptoms could have lung cancer, or it could be something else. If you have these symptoms, your best bet is to see your doctor. Your doctor can say for sure what's causing the symptoms and how to treat them.

Lung cancer is usually caused by smoking – but not always. Researchers say that more than 90% of lung cancers in men and at least 70%  in women are directly caused by cigarette smoking. Lung cancer can also be caused by other things. Some people who have lung cancer have never smoked a day in their lives. Their cancer may be caused by something else, like:

  • Second-hand smoke. People who regularly breathe second-hand smoke have almost double the risk of getting lung cancer than people who stay away from smoke. It's a fact: Non-smokers who live or work in smoky air can get lung cancer from second-hand smoke.
  • Radon. Radon is a colourless, odourless gas found in the soil. Radon can enter buildings through cracks in the foundation or insulation, or through drains or walls. Radon can get trapped in basements and other places that don't have a lot of air flow (fresh air). People who have a high exposure to radon are at higher risk of lung cancer. Read more about radon, an invisible gas that can cause lung cancer
  • Asbestos. Asbestos is a heat-resistant mineral found in some workplaces and homes. It has been used in brake pads, insulation, siding, and many other products. People who have a high exposure to asbestos are at higher risk of lung cancer. Read more about asbestos and how it can cause lung disease
  • Other toxic products: uranium, arsenic, some petroleum products may also increase the risk of developing lung cancer

Tests & Diagnosis:
There are many tests and exams used to diagnose lung cancer. Your doctor may use some of these tests. Not all tests are necessary or appropriate for every person:

  • Your Medical History. Your doctor may ask:
  •      What medical problems have you had?
  •      Have you smoked? How much and for how long? Have people around you smoked?
  •      Where have you lived and worked, what kind of work have you done?
  •      What is your family history of cancer?
  •      What symptoms have you noticed?
  • Physical Exam
  • Chest X-ray
  • Sputum Analysis. The doctor collects your sputum (the phlegm you cough up) and tests it for cancerous cells.
  • Bronchoscopy. You may need to be sedated (to "go under" general anesthesia) for this test. The doctor slides a thin, flexible tube (a bronchoscope) through your mouth or nose and into your lungs. The bronchoscope can help find tumours. If it finds a tumour, it can break off a small piece of it. Doctors examine this tumour piece under a microscope to help make the diagnosis.
  • Needle Biopsy. The doctor gives you local anesthesia so you don't feel pain, and then slides a thin needle into your chest. The needle collects a small piece of the tumour, which doctors examine under a microscope.
  • Mediastinoscopy. This test helps your doctor know if the cancer has spread to any of your lymph nodes (glands in your body's lymphatic system). First, you will be put under general anesthesia (in a deep sleep). The doctor makes a small cut in your neck and inserts a thin tube. The tube collects fluid samples and biopsies (pieces of tissue) from the lymph nodes near your throat and lungs. The samples are tested for cancerous cells.
  • CT Scan (also called a CAT scan or Computerized Axial Tomography) This  scan takes many detailed X-rays that are blended together by a computer. You lie in a long tube of the CT scan machine and stay very still as the X-rays are being taken. After the first scan, you may get an injection of dye to help the CT scan take a clearer picture. The CT scan is painless but you may find it uncomfortable to stay still. The CT scan gives very accurate information about your condition.


Where Can I Get More Information and Support for Lung Cancer?

The Canadian Cancer Society, a non-profit organization, offers in-depth information on lung cancer, on its website, a toll-free phone line for questions on cancer, as well as peer support and in-person support groups.

Lung Cancer Canada, a non-profit organization, offers a peer support program that matches people with lung cancer (and their families and caregivers) with people who have been in similar circumstances. They also offer an information service staffed by trained volunteers.


Page Last Updated: 29/07/2022