Cancer rates declining in Canada but cases, deaths increasing because of demographic factors

Canadian Medical Association Journal

Overall cancer rates in Canada are declining, but the number of cases and deaths are increasing slightly because of population growth and an aging population, according to a new study on cancer data published in CMAJ (Canadian Medical Association Journal) https://www.cmaj.ca/lookup/doi/10.1503/cmaj.212097.

The study is the result of a collaboration between the Canadian Cancer Society, Statistics Canada and the Public Health Agency of Canada. It estimates that there will be 233,900 new cancer cases and 85,100 cancer deaths in Canada in 2022 and provides provincial, territorial and national estimates. This is up from an estimated 229,200 cancer cases and 84,600 cancer deaths in 2021.

In Canada, cancer is the leading cause of death, and 43% of all people in the country are expected to receive a cancer diagnosis in their lifetime, according to previous estimates.

“Cancer control efforts are having an impact on cancer in Canada,” said Dr. Darren Brenner, an epidemiologist at the Cumming School of Medicine, University of Calgary and an author of the study. “The overall age-standardized rates of new cases and deaths continue to decline, in large part because of efforts in cancer prevention, screening, early detection and treatment. There has also been an overall increase in survival among people in Canada diagnosed with cancer, which is good news.”

Key points:

  • Lung cancer is projected to be the most common cancer in 2022, with an estimated 30,000 new cases, followed by breast (28,900 cases), prostate (24,600) and colorectal (24,300) cancers.
  • These 4 cancer types will make up almost half (46%) of all cancers expected to be diagnosed in Canada in 2022.
  • In males, prostate cancer is projected to be the most commonly diagnosed cancer, about 1 in 5 cancer diagnoses, followed by lung cancer.
  • Breast cancer is expected to be the most commonly diagnosed cancer in females, about 1 in 4 cancer diagnoses, followed by lung (13%), colorectal (10%) and uterine (7%) cancers.
  • The age-standardized mortality rate in males is estimated to be 34% higher than in females.

Although mortality and survival for many types of cancer have improved considerably over the past 3 decades, for others, additional research and investment into novel therapies are needed. For example, the limited progress in early detection of and treatment for pancreatic cancer explains why it is the third leading cause of cancer death in Canada despite being the 11th most commonly diagnosed cancer.

“The 2022 projections remind us that we need to do more to change the future of cancer in Canada,” says Elizabeth Holmes, Senior Manager of Health Policy at the Canadian Cancer Society and an author of the study. “To reduce the number of people being diagnosed with cancer and ensure more people survive a diagnosis, we must continue to invest in and support innovative research and effective public health policies with implementation across the cancer control spectrum.”

“Projected estimates of cancer in Canada in 2022” is published May 2, 2022.

A commentary published in the same issue of CMAJ discusses why and how a test for high-risk human papillomavirus (HPV) will replace the Papanicolaou (Pap) test for routine cervical cancer screening in Canada https://www.cmaj.ca/lookup/doi/10.1503/cmaj.211568.

Over the last 50 years, cervical cancer rates have declined in Canada with the introduction of screening programs. In 2022, cervical cancer rates are predicted to be 7.5 per 100,000 and are expected to decline in the future with widespread vaccination against HPV and HPV testing as a primary screening test.

“A change to HPV PCR testing for cervical screening represents a rare instance in which a more sensitive screening test is found to be both more cost-effective and more responsive to the changing disease incidence that will result from successful HPV vaccination programs,” write Drs. Emily Delpero and Amanda Selk, obstetricians/gynecologists at Women’s College Hospital and Sinai Health System, Toronto. “However, international experience highlights the importance of early and broad public and provider education in ensuring a smooth and successful transition.”

“Shifting from cytology to HPV testing for cervical cancer screening

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