Cancer Prevalence

Key findings

Female breast cancer was the largest contributor to 10-year prevalence (patients diagnosed between 2007 and the end of 2016), accounting for 74,689 prevalent cases. This reflects the high incidence and survival of breast cancer. Prostate (72,289) and colorectal (47,032) cancers were the next most prevalent cancer types.

Why is this important to Ontarians?

Prevalence describes the number of people diagnosed with cancer in a population who are still alive at a given time. It includes those diagnosed within a specific period (such as within the past 10 years), including those who have been recently diagnosed. Prevalence statistics depend on both incidence and survival. Both incidence and survival rates have been increasing in Ontario, so prevalence over time has also been increasing.^[1]

Trends in cancer prevalence can help determine the allocation of diagnostic, treatment and care resources.^[2] Cancer cases diagnosed in the previous 10 years (i.e., between 2007 and the end of 2016) represent the greatest impact on the healthcare system.

See Cancer Prevalence Methodology for technical information.

Note: Prevalence is based on specific cancer type. A person diagnosed with more than 1 type of cancer in that 10-year period will be included in the count for each type of cancer. However, if a person is diagnosed with more than 1 of the same cancer type (e.g., 2 colorectal cancers), only 1 episode of the cancer will be included in the prevalence estimate.

Data Table 1. Ten-year prevalence for the 4 most prevalent cancers, Ontario, as of January 1, 2017
Cancer type	Number of prevalent cases
Breast (female)	74,689
Colorectal	47,032
Lung	21,157
Prostate	72,289

Data Table 1. Ten-year prevalence for the 4 most prevalent cancers, Ontario, as of January 1, 2017

Results

As of January 1, 2017, 74,689 women living in Ontario had been diagnosed with breast cancer within the previous 10 years (i.e., since 2007). During the same period, 72,289 men living in Ontario had been diagnosed with prostate cancer. The prevalence for both cancers is high because of their high incidence and survival rates.
Although colorectal cancer is one of the most common cancers in Ontario, the 10-year prevalence for this cancer was only 47,032. This reflects the fact that colorectal cancer has lower survival than breast and prostate cancers.
Of the top 4 most common cancers, lung cancer prevalence ranks lowest (21,157) because it has lower survival rates than breast, prostate and colorectal cancers.
Despite increasing cancer incidence, more effective treatments and early detection have resulted in more Ontarians surviving cancer with each passing year. As a result, many cancers are now managed as chronic conditions.

For more information

Find more information on cancer incidence, mortality, survival and prevalence in Ontario in Ontario Cancer Statistics 2020.

Find information on cancer statistics across Canada in Canadian Cancer Statistics.

References

[1] Cancer Care Ontario. Ontario Cancer Statistics 2018. Toronto: Cancer Care Ontario; 2018.

[2] Micheli A, Mugno E, Krogh V, Quinn MJ, Coleman M, Hakulinen T, et al. Cancer prevalence in European registry areas. Ann Oncol. 2002;13(6):840-65.