Research has shown that screening with low-dose computed tomography (CT) using lower doses of radiation (low-dose CT) is effective in detecting lung cancer early in people who have a history of heavy smoking. Lung cancer screening tests using chest x-rays and a sputum test is not recommended [19].
As of right now, there are no provincial or territorial lung cancer screening programs in place in Canada. The Canadian Task Force on Preventive Health Care (CTFPHC) recommends low-dose CT screening once a year for three years for people who meet the criteria below. The CTFPHC recommends screening for lung cancer in persons who are [20]:
- Aged 55 to 74 –this is the age group where the evidence says lung cancer is the most effective
- Smokers or former smokers who have quit in the last fifteen years
- Smokers who have smoked one pack a day for at least thirty years or two packs a day for fifteen years, equalling ‘thirty pack years’
These are recent changes made to the CTFPHC guidelines, based on recent studies, including a clinical trial that found 15 per cent reduction in lung cancer deaths among those screened with a CT scan compared to a chest x-ray [21].
The new recommendations do not apply to people with a family history of lung cancer or those with symptoms suggestive of lung cancer. It is unknown whether or not people who suffer from other risk factors such as exposure to radon, second-hand smoke or previous radiation to the chest would benefit from low-dose CT screening [22].
Some risk is incurred from screening for lung cancer: false-positives–wherein a test suggests that a patient has lung cancer when no cancer is present, which can lead to unnecessary follow-up tests and surgeries [23]. Other risks include finding a cancer that would cause illness or death or complications from the tests needed to follow up the CT scan results. There is also an exposure to some radiation during a CT scan [24].
Provincial and territorial screening programs
There are no current lung cancer screening programs in any provinces or territories but the Lung Cancer Screening Framework for Canada is a consensus-based framework model designed as a tool to support Canadian jurisdictions in planning for lung cancer screening by outlining elements for consideration [25].
While the guidelines released by the Canadian Task Force on Preventive Health Care target and succeed in the reduction of lung cancer mortality in a high-risk population, screening needs to be monitored and controlled in order to limit the risk of false positive results and ensure appropriate patient follow-up.
References
[19] “Finding Lung Cancer Early.” Canadian Cancer Society. Canadian Cancer Society, 2016. Web. 29 Mar. 2016.
[20] ibid.
[21] Ubelacker, Sheryl. “New Guidelines Urge Lung Cancer Screening in Longtime Smokers.” Toronto Star. Toronto Star, 7 Mar. 2016. Web. 29 Mar. 2016.
[22] ibid.
[23] “What Screening Tests Are There?” Centers for Disease Control and Prevention. Centers for Disease Control and Prevention, 14 Mar. 2016. Web. 29 Mar. 2016.
[24] “Finding Lung Cancer Early.” Canadian Cancer Society. Canadian Cancer Society, 2016. Web. 29 Mar. 2016.
[25] “Lung Cancer Screening in Canada.” Cancerview.ca. Canadian Partnership Against Cancer, Mar. 2016. Web. 06 Apr. 2016.