Lung Cancer Screening in Canada
Canada continues to be an important contributor to the global base of lung cancer research and breaking new ground in the area of screening and diagnostics. Dr Stephen Lam MD, FRCPC Chair, Lung Tumor Group & Judah Leon Blackmore Chair, BC Cancer Agency Professor of Medicine University of British Columbia led a Canadian team who showed that a risk prediction tool to detect early stage lung cancer in high-risk individuals is superior in terms of accuracy compared to other models. The Pan Can Lung Cancer Risk Prediction Model is used to determine if a person should undergo annual computed tomography (CT) screening to detect early-stage lung cancer. The new approach outperformed current screening inclusion criteria such as The US Preventive Services Task Force recommendation. Currently, both the U.S. and Canadian lung cancer screening guidelines are based on age and smoking history. But the Pan Can Model also looks at numerous additional variables such as sex, family history of lung cancer, chronic obstructive pulmonary disease, educational level, and body mass index. Artificial intelligence is starting to become more common in the lung cancer screening discussion. “This is the future,” says Dr Lam. “Artificial intelligence to read CT scans that can accurately detect lung nodules and other changes in the lung, to determine an individual’s risk for lung cancer is where the next innovation in screening will come”. Presented at the World Lung Conference in Toronto this past fall, the Dutch-Belgium NELSON-trial, which is a population-based randomized control trial comparing CT screening with no screening in ever smokers between the age of 50 to 74 years who have smoked at least 15 cigarettes a day for 25 years or more or at least 10 cigarettes a day for 25 years or more and have smoked within 10 years. Between 2004 and 2006, the study enrolled 15,822 participants. The CT screening received a baseline CT and three additional screenings at intervals of 1, 2 and 2.5 years. Analysis at 10 years of follow-up showed a significant 26% reduction in lung cancer mortality in men and up to 61% reduction in mortality in women compared to the no screening group. With two global, large randomized trials demonstrating significant mortality reduction, we now have clear evidence to support the implementation of lung cancer screening similar to breast and colorectal screening that save the lives of countless individuals. New research projects are very important in the area of lung cancer. Despite being Canada’s deadliest cancer killer, lung cancer receives some of the lowest funding for research compared to other cancers.
Lung Cancer Screening Saves Lives
In lung cancer, early detection is everything. The earlier lung cancer is diagnosed, the better the opportunity for curative treatment. If a high-risk individual is diagnosed before the onset of symptoms when the cancer is in an early stage, the chances of survival are very good. Dr Lam estimates that up to 75% of patients diagnosed with advanced lung cancer are incurable, but this ratio can be reversed. With the proper screening protocols in place the odds dramatically shift and 75% of the diagnoses are at an early stage when curative treatment is possible. Much of the great improvement that has been seen in survival in cancers such as breast, colorectal and cervical have been due to finding the cancers earlier through regular testing, even of those at just moderate risk, such as from age. However, almost half (49.9%) of lung cancer diagnoses are made only when the cancer is already at stage 4, the most advanced stage, meaning it has already spread outside of the lung, and a further 19.7% of cases are diagnosed at stage 3. [Health Statistics Division, Statistics CanadaData Source; Canadian Cancer Registry database at Statistics Canada]. The mortality rate at these stages is extremely high, with a 5 year relative survival rate for stage 4 lung cancer at only 1% (2007)2. In comparison to the 5 year survival rate for stage 1A lung cancer, which is 49%, the difference is substantial. The newest screening method, low-dose computed tomography (LDCT) screening, offers much greater promise by yielding a more comprehensive view of the lung tissue while exposing patients to only 20% of the normal CT scan radiation. According to the Canadian Cancer Society Statistics publication of 2018, microsimulation modeling predicts that 1.4 million Canadians would be eligible for high-risk screening in 2018 (OncoSim, version 2.5)1
Lung Cancer Screening Saves Money
When cancers are detected early, the cure rate improves and we eliminate the costs of treating at a late stage, which is the more expensive stage. In Canada, the Pan-Canadian Early Detection of Lung Cancer Study examined both how to incorporate lung cancer screening into our health care systems, and how much it would cost. This study found that screening has the potential to save the health care system a significant amount of money. In this study, the average cost to screen individuals at high risk for developing lung cancer using LDCT was $453 for the initial 18 months of screening following a baseline scan. If a patient can be treated using curative surgery, the average cost was $33,344 over two years. This is significantly lower than the average per person cost of $47,792 used in treating advanced-stage lung cancer with chemotherapy, radiotherapy or supportive care alone. [Cressman S, Lam S, Tammemagi MC et al, Resource Utilization and Costs During the Initial Years of Lung Cancer Screening with Computed Tomography in Canada. Journal of Thoracic Oncology. 9:10 October 2014] The recommendation for lung cancer screening is a significant one. To date, no province has adopted a comprehensive lung cancer screening program. Lung Cancer Canada believes that lung cancer screening can save lives and lessen the significant burden on the healthcare system. Lung Cancer Canada calls on all provinces and territories to adopt screening programs that, at the very least, target patients with the highest risk of lung cancer.
The Canadian Task Force on Preventive Health Care now recommends screening for lung cancer with three consecutive annual low-dose computed tomography (CT) scans in high-risk individuals adults aged 55-74 years who currently smoke or quit less than 15 years ago, with a smoking history of at least 30 pack-years. A pack year is defined as the average number of packs smoked daily multiplied by the number of years of smoking. In addition, pilot studies are currently underway in Canada to investigate the feasibility of implementing lung cancer screening programs for high-risk populations1.The over-all aim of these programs is to detect disease at an earlier stage where it may respond better to treatment and chances of survival are higher1. This is a big step in the fight against lung cancer, which is the leading cause of cancer related death in Canada.
Currently there is no formal lung cancer screening program in Canada, however there are pilot programs underway for which you may be eligible. As healthcare is under provincial jurisdiction, each province will need to design and adopt their own formal program. Hospitals and clinics across the country do have teams and the expertise to conduct lung cancer screening so speak to your family physician to get a referral or call your provincial cancer association to help identify a centre with expertise. In addition, some provinces and territories have initiated lung cancer screening strategies such as preparing business cases, convening advisory committees, and planning or implementing pilot studies3.
To assess your level of risk and get more info, visit MyCancerIQ.
For more information on Ontario's pilot program, view the CCO Lung Cancer Screening Program FAQs
The Canadian Task Force for Preventative Health recommends screening using low-dose CT scans in high-risk adults aged 55-74 years who are current or former smokers with a smoking history of at least 30 pack-years, defined as the average number of packs smoked daily multiplied by the number of years of smoking. If you have quit smoking, you must have quit within the last 15 years. This recommendation is aligned with other expert and cancer agency recommendations as well.
The Canadian Task Force on Preventive Health Care showed that the number needed to screen (NNS) for lung cancer is 3222. This means that out of 322 people in the high risk population that are screened for lung cancer, one person will be diagnosed with lung cancer2. In comparison, the NNS for breast cancer (age 50-69) is 7214.
CT scans carry the risk of exposure to radiation and a positive scan could lead to an invasive procedure such as a lung biopsy. Due to this, screening should be monitored and controlled in order to minimize harms and maximize the benefits through appropriate follow-up. Lung cancer screening is only recommended to those that have been identified as high risk.
Currently no province has a formal screening program. However hospitals and clinics across the country have teams and the expertise to conduct lung cancer screening. Speak to your family physician to get a referral or call your provincial cancer association to help identify a centre with expertise.
1 Canadian Cancer Statistics Advisory Committee. Canadian Cancer Statistics 2018. Toronto, ON: Canadian Cancer Society; 2018. Available at: cancer.ca/Canadian-Cancer-Statistics-2018-EN
2 Canadian Task Force on Preventive Health Care. “Recommendations on Screening for Lung Cancer.” CMAJ, CMAJ, 5 Apr. 2016, www.cmaj.ca/content/188/6/425.
3 Canadian Partnership Against Cancer. Lung Cancer Screening in Canada: Environmental Scan. Toronto, ON: Canadian Partnership Against Cancer; 2018
4 Seely, J M, and T Alhassan. “Screening for Breast Cancer in 2018-What Should We Be Doing Today?” Current Oncology (Toronto, Ont.), Multimed Inc., June 2018, www.ncbi.nlm.nih.gov/pmc/articles/PMC6001765/.