Canada’s most common and most deadly cancer being fought at last by screening programs

Lung cancer screening for those at risk in Canada’s three largest provinces

“Cancer” is many different diseases, depending primarily on where it originates in the body. One thing they generally have in common, however, is that the earlier cancer is discovered and diagnosed, the better the likelihood for a positive outcome.

That is typically measured by determining the “stage” of cancer when it is found. Stage 1, the earliest, means it is limited to a defined location and hasn’t yet spread, while Stage 4, the most advanced, means it has spread beyond where it started.

Some cancers are more easily found at early stages. For example, more than 81% of breast cancer cases in Canada are diagnosed at an early stage (1 or 2) and less than 5% are diagnosed at Stage 4.1 In addition to new treatments, catching it early is a big reason why the five-year survival rate for breast cancer is higher, at 89%.2

It’s not the same story for lung cancer. About half of cases are diagnosed at the most advanced stage 4, and this rises to two-thirds for the more aggressive form of the disease, small cell lung cancer. Just a fraction (7%) of small cell lung cancers are diagnosed at either stage 1 or 2.3 The five-year survival rate for lung cancer is just 22%.4

Why does this happen and how can it be fixed?

One obvious reason for the difference in when breast cancer and lung cancer is diagnosed is that sometimes a breast lump or change can be visually detected while lung cancer symptoms can be harder to detect given the symptoms can also be associated to other conditions or diseases. But another important reason is that for decades there have been programs and campaigns to encourage women, particularly those at most risk, to be screened regularly for breast cancer with mammograms and other tests.

Colorectal cancer is an example of a type of cancer that often can’t be seen or felt but for which there have been many longstanding and well-publicized screening programs involving stool tests and colonoscopies. The result is that almost half of colorectal cancer cases are found at the early stages 1 or 2,5 and the five-year survival rate is 67%.6 Screening and early detection works.

Until recently, there were no organized screening programs for lung cancer even though it is the most common cancer in Canada, with almost 30,000 cases per year. It’s also the most deadly, causing 21,000 deaths per year, a quarter of all Canadian cancer deaths.7

Without comprehensive screening programs, the disease is usually discovered when a lung x-ray or scan is taken for another reason or when patients notice a symptom, often an unusual pain or cough, and have it checked. By which time, the cancer is often well advanced.

Lung cancer screening in Ontario, Quebec and BC

Fortunately, that is now changing. Canada’s three largest provinces are starting programs to screen people at the highest risk for lung cancer. The programs provide people at high risk with the chance to have regular scans of their lungs using low-dose computed tomography (CT) scanners.

The scans aim to find lung cancer earlier and therefore increase the probability that treatment will be more effective. In a major study conducted in the U.S, such CT screening programs were shown to reduce lung cancer deaths by 20% compared to screening with x-rays, and found cancers at much earlier stages.8

The criteria for taking part are slightly different in each province but in general they are for older people (55 to 74 years old) who have smoked tobacco for many years.9,10,11

“We are at a tipping point now in Canada with BC, Ontario and Quebec launching lung cancer screening programs and it should just be a matter of time before we see programs in the other provinces,” said Dr. Paul Wheatley-Price, a medical oncologist at the Ottawa Hospital Cancer Centre and former president of Lung Cancer Canada.

“With our population ageing, this is a prime time to be starting programs like this and I’m confident that in five years we’ll be seeing many more lung cancer cases diagnosed at early stages. We’d like to see lung cancer screening added to family doctors’ routine practice like mammograms, prostate check and Pap smears are.”

The Canadian Cancer Society says that organized lung cancer screening programs in Canada over the coming 20 years could lead to 7,000 to 17,000 fewer stage 4 diagnoses and 5,000 to 11,100 fewer deaths.12

The further good news is that new treatments for lung cancer are helping those who get diagnosed, particularly at the early stages.

“There has been a revolution in lung cancer care over the past decade, with new targeted therapies based on the genetic make-up of the cancer and new immunotherapies using the body’s immune system to fight cancer. And now we have the promise of more screening finding cases earlier. This is all very positive news,” said Dr. Wheatley-Price. “I encourage everyone who thinks they may be at risk for lung cancer, to ask their doctor whether lung cancer screening is available for them.”

It’s also important to realize that lung cancer can affect anyone, regardless of smoking history, and that we all need to remain alert to the signs of possible lung cancer and to seek medical help without delay, despite the pandemic. If it’s lung cancer, the earlier the diagnosis and start of treatment, the better the chances for a successful outcome.

Common symptoms of lung cancer include: 13

  • Pain in the chest, shoulder, back, or arms
  • Recurrent lung infection (pneumonia or bronchitis)
  • Worsening or persistent cough that lasts for three or more weeks
  • Fatigue
  • Shortness of breath
  • Coughing up blood
  • Hoarseness or changing voice
  • Loss of appetite or unexplained weight loss

Less common symptoms of lung cancer include: 14

  • Wheezing
  • Swelling in the face or neck
  • Blood clots
  • Weakness or dizziness
  • Bone pain or fractures
  • Painful lumps (swollen lymph nodes) in the neck or near the collarbone


Resources on lung cancer screening

Resources on lung cancer symptoms


No content of this article is intended as medical advice. If you have questions about your health, consult a healthcare professional.

Developed by C.A.R.P./Zoomer with financial support from Merck Canada Inc.


[1] Canadian Cancer Society, Canadian Cancer Statistics: A 2018 special report, Cancer incidence by Stage, Figure 5, p. 20.

[2] Canadian Cancer Society, Canadian Cancer Statistics 2021, Table 3.1, p. 62.

[3] Canadian Cancer Society, Canadian Cancer Statistics: A 2018 special report, Cancer incidence by Stage, Figure 1, p. 15.

[4] Canadian Cancer Society, Canadian Cancer Statistics 2021, Table 3.1, p. 62.

[5] Canadian Cancer Society, Canadian Cancer Statistics: A 2018 special report, Cancer incidence by Stage, Figure 3, p. 18.

[6] Canadian Cancer Society, Canadian Cancer Statistics 2021, Table 3.1, p. 62.

[7] Canadian Cancer Society, Lung Cancer Statistics,

[8] National Cancer Institute, National Lung Screening Trial (NLST),

[12] Canadian Cancer Society, Critical Canadian projections for Lung Cancer Awareness Month, Nov. 24, 2020,

[13] Lung Cancer Canada, Symptoms:

[14] Lung Cancer Canada, Symptoms: