Highlights
- The 5-year relative survival ratio for all cancers combined improved in Ontario, from 47.6% in 1983–1987 to 62.5% in 2008–2012.
- The 4 most common cancers in Ontario—prostate, female breast, colorectal and lung—all experienced an increase in their 5-year relative survival ratios.
- The 5-year relative survival ratio is an important indicator of the effectiveness of cancer treatments and cancer control programs.
The age-standardized 5-year relative survival ratio (RSR) from cancer in Ontario has improved over the past 3 decades, rising from 47.6% in 1983–1987 to 62.5% in 2008–2012. This means that people diagnosed with cancer between 2008 and 2012 were estimated to be 62.5% as likely to survive for another 5 years as people of the same age and sex in the general population.
The 5-year RSR also increased for most individual types of cancer between 1983–1987 and 2008–2012, including the 4 most commonly diagnosed cancers in Ontario: prostate, female breast, colorectal and lung. Together these account for almost half of all cancers diagnosed in 2012.
Improvements in survival over time can be attributed to more effective treatments, as well as greater use of early detection—screening increases survival by allowing cancers to be detected at earlier stages when they are usually more treatable. Even small improvements in survival can reflect a large number of avoided premature deaths.
The 5-year RSR was highest for prostate cancer (93.9% in 2008–2012), which has had a consistently high RSR over all the time periods shown in the figure. The 5-year RSR for breast cancer rose from 72.8% in 1983–1987 to 86.1% in 2008–2012, due, in part, to the implementation of the Ontario Breast Screening Program in the late 1980s.
The 5-year RSR for colorectal cancer increased from 50.2% in 1983–1987 to 64.5% in 2008–2012, while the RSR for lung cancer rose from 13.6% to 19.6% over the same time period. Although this increase in lung cancer appears modest, it actually represents a considerable improvement because survival is so low for this cancer type. Lung cancer consistently had the lowest survival of the 4 most common types of cancer over the 6 time periods shown in the figure because most cases are not detected until they are at an advanced stage and the cancer has spread beyond the lungs.
Survival statistics are a key indicator of the effectiveness of cancer treatment and control programs. The first 5 years after diagnosis are critical for examining survival, and usually involve services such as primary treatment and close clinical assessment for recurrence. After 5 years, the use of the healthcare system and the chance of recurrence both decrease.
For more information on the burden of cancer in Ontario through 4 major types of indicators—incidence, mortality, survival and prevalence—see Ontario Cancer Statistics 2016