Brock-led Research Demonstrates Effectiveness of Lung Cancer Prediction Model in Ontario Screening Program

An Ontario lung cancer screening pilot based on a prediction model developed by a Brock Professor Emeritus was highly successful in catching the disease in its early stages, says new research.

Lung cancer is the leading cause of cancer-related deaths worldwide according to the World Health Organization, with smoking recognized as the greatest risk factor for developing the disease.

Professor Emeritus of Epidemiology Martin Tammemägi has been working with Cancer Care Ontario for a decade as Scientific Lead to create and implement its Lung Cancer Screening Pilot for People at High Risk. During the pilot, health-care workers screened 4,451 people identified by Tammemägi’s model to be at high risk for developing lung cancer between June 2017 and May 2019.

His work demonstrates that a cancer screening program using a risk assessment model can be successfully implemented in a universal healthcare medical system, concludes the paper published in Nature Medicine last month.

Following the end of the pilot in 2021, the Ontario health system formally implemented the Ontario Lung Screening Program using Tammemägi’s lung cancer prediction model to determine who gets screened. He says the program is expanding from the current five sites to cover most regions of Ontario by 2026.

The model estimates an individual’s personalized level of risk using the number of cigarettes smoked per day, the number of years of smoking, race or ethnicity, age, highest level of education obtained, family history of lung cancer and body mass index among other factors.

The model is accompanied by mathematical equations to predict the risk of an individual getting lung cancer. Those deemed to be at elevated risk then undergo low-dose computed tomography (CT) screening.

Since the end of the pilot, a team of 44 Cancer Care Ontario researchers headed by Tammemägi have been evaluating the program’s effectiveness, publishing the results in the recent Nature Medicine paper.

The team’s findings include:

• Lung cancer was detected in 2.4 per cent of screened individuals, with 79.2 per cent of them being early-stage, potentially curable cancers.
• Serious harms, such as serious complications, unplanned hospitalizations or deaths were infrequent or rare.
• Lung cancer screening detected more than 95 per cent of all the lung cancers occurring in the pilot participants.
• 85 per cent or more of participants adhered to follow-up requirements, including annual scans, early scans and further clinical testing. This is important in making lung cancer screening programs effective and efficient and is a much higher adherence rate than observed in most other screening centres.

“The valuable lessons and processes learned through the Ontario Pilot can now help inform the multiple sites across Canada and the world as to how to lung cancer screen more effectively,” says Tammemägi.

The Ontario Health (Cancer Care Ontario) Lung Cancer Screening Pilot findings are in sharp contrast to the performance of lung cancer screening programs in the U.S., one of the jurisdictions discussed in the paper and a long-term research focus for Tammemägi.

While lung cancer was detected in 2.4 per cent of the individuals screen using Tammemägi’s model in Ontario, less than half of this cancer detection rate was observed in the U.S. National Lung Screening Trial.

American lung cancer screening programs use the U.S. Preventive Services Task Force’s guidelines, which Tammemägi says rely on relatively simplistic screening eligibility rules.

Ontario’s follow-up adherence rate was also more than double that seen in the U.S. Tammemägi attributes this to the availability universal health care in Ontario, the use of health-care professionals called “navigators” who help guide the participants journey through the screening process, and participants following primary care provider recommendations.

There are currently 209 lung cancer screening clinical trials around the world, with implementation studies and regional or national programs in 39 countries.