About the disease
Lung cancer is the leading cause of death due to cancer in Canada, representing an estimated 30% of the cancer deaths in males and 25% of the cancer deaths in females.
In Alberta in 2003, 881 males and 730 females were diagnosed with lung cancer. In the same period, 733 males and 556 females died of their disease.*
Lung cancer is cancer that starts in the lungs. There are two major types of lung cancer. Each type of lung cancer grows and spreads in different ways, and may be treated differently.
Non-small cell lung cancer: this is the most common type of lung cancer. It usually spreads more slowly than some 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. There are three major types of small cell lung cancer:
- Small cell carcinoma
- Mixed small cell/large cell
- Combined small cell carcinoma
Risk factors
Risk factors are determined by analyzing the numbers of patients with cancer in a large population sample and trying to find differences in the characteristics or behaviors between those who develop cancer and those who do not. The Alberta Cancer Board’s Tomorrow Project, for instance, is tracking more than 50,000 Albertans over a 50-year period to learn more about who develops cancer and why.
Tobacco use is the single most important preventable cause of lung cancer. Researchers estimate that more than 90% of lung cancers in men and at least 70% in women are directly caused by cigarette smoking.
Other factors that may increase the risk of developing lung cancer include:
- Exposure to second-hand smoke: People who regularly breathe in other people's smoke have almost double the risk of getting lung cancer than people who stay away from smoke. Non-smokers who live or work in smoky air can get lung cancer from second-hand smoke.
- Radon: Radon is a gas found in the soil in many parts of the country. Radon can enter a building through cracks in the foundation or insulation, or through drains or walls. People who have a high exposure to radon at home, school and work are at higher risk of lung cancer.
- Asbestos: asbestos is found is many workplaces and homes. In the past, it has been used in oven, brake pads, insulation, and many other industrial products
- Other toxic products: uranium, arsenic, some petroleum products may also increase the risk of developing lung cancer
Factors that may decrease the risk of developing lung cancer include:
- Not smoking. If you smoke, quit: Choosing not to smoke is the very best way to prevent lung cancer. If you do smoke, quit. If you've tried to quit and it didn't work, try again. As soon as you quit smoking, your risk or lung cancer goes down. The sooner you quit, the lower your risk. It's never too late to quit smoking.
- Avoiding second-hand smoke and exposure to radon, asbestos and other known toxins.
Genetic Links
Genetic links have been identified that increase risk of lung cancer; these links are thought to be related to an individual’s metabolism of carcinogens in tobacco smoke.
Links:
The Tomorrow Project
Symptoms raising suspicion of 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
Detection and diagnosis
Anyone who presents with the symptoms noted above should consult with their physician. Your family doctor will ask you about your general health and examine you and then refer you for chest x-rays and other tests as required. Your doctor may test samples of phlegm that you have brought up so it can be examined for cancer cells.
Other diagnostic tests may include:
CT scan
This is a type of X-ray that takes pictures from different angles. The pictures are fed into a computer and form a detailed picture of the inside of your body. You are likely to have a CT scan done before having a bronchoscopy or biopsy. The scan can show the area where the cancer is. You will have an injection of dye before the scan to help show up abnormalities.
Bronchoscopy
This test looks at the inside of the airways. A narrow, flexible tube called a bronchoscope is put down your throat and into the airway. The bronchoscopy set-up uses a fibre-optic system that allows the operator to view the images directly on a video screen. Your doctor can also take samples of tissue and cells (biopsies ) during a bronchoscopy.
Percutaneous Lung biopsy
For this test, the doctor uses a thin needle to take samples of cells for examination under the microscope. The test can be uncomfortable but only takes a few minutes. If it is difficult to get enough tissue under local anaesthetic, the doctor can perform an 'open' lung biopsy under general anaesthetic.
Mediastinoscopy
This is a test which examines the mediastinum. This is an area in the centre of your chest, between your lungs, which contains
- The heart
- Main blood vessels
- Lymph nodes
The doctor makes a small cut at the base of the neck, and puts a small tube through the cut and into the mediastinum. The doctor can look through this tube to examine the area and take tissue samples to biopsy the lymph nodes and determine if surgery is indicated.
Thoracoscopy
Doctors use this test to
- Find the cause of fluid on the lung (pleural effusion)
- Take tissue samples from the lung
- Take tissue samples from lymph nodes in the centre of the chest (mediastinum)
You have this test under sedation or sometimes a general anaesthetic. You will probably have about 2 or 3 cuts (incisions) in your chest on the side the doctor is investigating. The doctor puts a tube in that is similar to bronchoscope. Through the tube, the doctor looks for anything abnormal and can take tissue samples (biopsies), or suck out a sample of fluid. The biopsies and fluid sample will be sent to the lab after the test to be checked for cancer cells.