Lung Cancer Types and Causes

The lung cancer usually begins to form in the mid-fifties or sixties. The smoking is responsible for 80% to 90% of cases of lung cancer.

This cancer is particularly menacing because it can be more easily spread in the rest of the body than other types of cancer. Indeed, all the blood passes through the lungs to be oxygenated, and the lungs are in close contact with several blood and lymphatic vessels. Lung cancer is all the more alarming because it is often discovered late. It is the leading cause of cancer death in Canada, both for men and women.

The Canadian Cancer Society predicts there will be 24,100 new cases of lung cancer in 2010 in the country: 12 900 men and 11 200 women 43 .

However, this cancer can be prevented very effectively by quitting or smoking less.


  • The smoking .
  • Exposure to second-hand smoke.
  • Exposure to carcinogenic particles present in the air , such as those arising from asbestos, arsenic, radon or air pollutants (carbon monoxide, ozone, etc.).

Facts about smoking and second-hand smoke

  • It was in the mid-1960s that the causal link between smoking and lung cancer was established with certainty.
  • In Canada, tobacco control efforts have paid off: in 1965, half of Canadians aged 15 and older smoked, compared to 25% in 1999 and 18% in 2008.
  • Through laws provincial, Canadians are much less exposed to secondhand smoke in the workplace and in public places.
  • Smoking is twice as common in Aboriginal populations as it is in the general Canadian population.
  • With the reduction in tobacco consumption, lung cancer has been declining since the mid-1980s among men. However, in women, this cancer has steadily increased since 1980 and is just beginning to stabilize.


There are two types of lung cancer. They grow and spread differently in the body.

  • Small cell lung cancer. This is the most dangerous form of lung cancer. About 20% of lung cancer cases occur in this form. At the time of diagnosis, the risk of cancer spreading elsewhere in the body is high. It grows rapidly and is often impossible to treat with surgery. Rather, chemotherapy and radiotherapy are used.
  • Non-small cell lung cancer. This form of lung cancer, which accounts for about 80% of cases , is detected and treated more easily than small cell cancer. It develops more slowly. This category includes 3 subgroups: adenocarcinoma , squamous cell carcinoma and undifferentiated large cell carcinoma . There are other forms, much more rare.


The lung cancer is among the deadliest, with pancreatic cancer . The survival rate of people with this cancer, 5 years after diagnosis, is 17% for women and 14% for men. Even if the person responds well to the treatment initially, relapses are common in the years or months that follow.


Lung cancer often obstructs the bronchi, which creates a terrain conducive to respiratory tract infections, such as bronchitis or pneumonia .

As mentioned earlier, cancer can spread to other parts of the body by forming metastases . Generally, metastases will lodge in other parts of the lungs, and in the bones, brain or liver. They are more common in cases of small cell lung cancer.