Media backgrounder: ComPARe study

08 May 2019

Toronto -

The Canadian Population Attributable Risk of Cancer (ComPARe) study, published today in Preventive Medicine, was the result of a partnership between the Canadian Cancer Society (CCS) and a pan-Canadian team of experts in epidemiology, biostatistics, cancer risk factors, cancer prevention and knowledge translation. The study provides estimates of the number and percentage of more than 30 cancer types in Canada due to more than 20 modifiable lifestyle, environmental and infectious agents risk factors using cancer incidence data from 2015.

Key findings of the ComPARe study

• Excess weight is expected to become the second leading preventable cause of cancer in Canada, after tobacco, by 2042

• About 4 in 10 cancer cases can be prevented through healthy living and policies that protect the health of Canadians

• Currently, the top 5 leading preventable causes of cancer are:
  1. smoking tobacco
  2. physical inactivity
  3. excess weight
  4. low fruit
  5. sun
Cancer prevention

• Preventing cancer holds promise in reducing the burden of this disease in Canada and the ComPARe study provides us with the information on the largest preventable contributors to cancer diagnoses to help inform and target cancer prevention activities.

• The top 5 things you can do to reduce cancer risk are:
  1. Live smoke-free
  2. Move more, sit less
  3. Have a healthy body weight
  4. Eat well
  5. Practice sun safety
Current burden by cancer type

• In total, the ComPARe study looked at more than 30 cancer types

• Cervical cancer is the most preventable cancer. Largely thanks to HPV vaccines, 100% of cervical cancers are preventable

• The next most preventable cancers are:
  • Lung cancer (86%)
  • Head and neck cancers (75%)
  • Stomach cancers (71%)
  • Melanomas (65%)
• Based on currently known risk factors, only 4% of advanced prostate cancers are preventable. The percentage would be even lower for all prostate cancers. This makes prostate cancer the least preventable cancer studied

• About 70,200 cancer cases could have been prevented in 2015

• Lung, breast and colorectal cancers are three of the most commonly diagnosed cancers in Canada. They also represent more than half of the preventable cancer cases
  • About 21,600 lung cancer cases could have been prevented in 2015
  • About 10,300 colorectal cancer cases could have been prevented in 2015
  • About 7,000 breast cancer cases could have been prevented in 2015
Current burden by risk factor

• In total, the ComPARe study looked at more than 20 modifiable risk factors

• The 5 modifiable risk factors that cause the highest number of cancer cases are smoking tobacco, physical inactivity, excess weight, low fruit and sun. In 2015, approximately:
  • 32,700 cancer cases were due to tobacco. This represents about 18% of all cancers diagnosed
  • 11,600 new cancer cases were due to physical inactivity
  • 7,200 new cancer cases were due to excess weight
  • 6,700 new cancer cases were due to low fruit
  • 4,300 new cancer cases were due to sun exposure
• About 18 in 100 cancer cases could have been prevented by living smoke-free

• About 18 in 100 cancer cases could have been prevented by eating well, being active and maintaining a healthy body weight

• About 4 in 100 cancer cases could have been prevented by reducing environmental exposures

• About 4 in 100 cancer cases could have been prevented by reducing exposure to infections

• About 3 in 100 cancer cases could have been prevented by decreasing exposure to cancer-causing substances in workplaces

Future cancer burden

• If we don’t make changes, then in 2042, 111,700 cancer cases will be due to modifiable risk factors

• If the trends we are currently seeing continue for the following risk factors, then in 2042, the number of new cancer cases due to:
  • smoking tobacco will increase from 32,700 to 46,900
  • excess weight will nearly triple, increasing from 7,200 to 21,200
  • physical inactivity will increase from 11,600 to 16,500
  • drinking alcohol will triple, increasing from 3,300 to 10,100
  • sitting too much will more than double, increasing from 3,200 to 8,500
Future burden if we change current trends

• If more Canadians:
  • had a healthy body weight, we could prevent about 110,600 cancer cases by 2042
  • quit or didn't start smoking, we could prevent about 50,200 cancer cases by 2042
  • limited their alcohol intake to less than 2 drinks a day for men and less than 1 drink a day for women, we could prevent about 44,300 cancer cases by 2042
  • were physically active, we could prevent about 26,200 cancer cases by 2042
  • practised sun safety, we could prevent about 12,000 cancer cases by 2042

About the ComPARe study

• The ComPARe study represents the most comprehensive, up-to-date study on the preventable burden of cancer in Canada.

• Results will:
  • have an important impact on cancer prevention decision-making in Canada
  • be directly relevant for guiding prevention research, informing program development, influencing behaviour change and advocating for new policies and interventions aimed at decreasing the burden of cancer in Canada
  • inform national and provincial policy makers about the risk factors and cancer sites most amenable to intervention(s) and help identify which cancer prevention policies could have the greatest impact
  • increase awareness about the biggest modifiable contributors to cancer in Canada and empower Canadians to take action in their own lives to reduce their cancer risk
• The ComPARe study is the first Canadian study of its kind and represents the most comprehensive, up-to-date study on the preventable burden of cancer in Canada
  • Previously, some studies outside of Canada have examined the burden of cancer due to modifiable risk factors and some Canadian studies have generated estimates of these numbers which were fragmented across provinces, risk factors and cancer types
  • No studies within Canada and few studies outside of Canada have modeled the joint effects of risk factors on cancer or examined the future preventable burden of cancer
For more information on the ComPARe study, please visit prevent.cancer.ca, or cancer.ca/prevention to learn more about how to reduce your risk of cancer.

Media release: Excess weight expected to become 2nd leading preventable cause of cancer, after tobacco

Media backgrounder: Excess weight

About the Canadian Cancer Society
The Canadian Cancer Society is a national community-based organization whose mission is the eradication of cancer and the enhancement of the quality of life of people living with cancer. When you want to know more about cancer, visit our website www.cancer.ca or call our toll-free, bilingual Cancer Information Service at 1 888 939-3333 (TTY 1-866-786-3934).


For more information, please contact:

Brooke Kelly

Communications Coordinator

Canadian Cancer Society

National office

Phone: 416-934-5321