Highlights
- Female breast, brain, lung and colorectal cancer are responsible for a large proportion of the total PYLL to cancer in Ontarians under age 50.
- PYLL is influenced by how common a cancer is, the average age someone is diagnosed at and how likely it is for the cancer to be fatal.
- The types of cancers responsible for the greatest number of PYLL differ when comparing the total population to people under age 50.
In Ontario in 2013, among people under age 50, female breast cancer was the biggest contributor of potential years of life lost (PYLL), accounting for 7,968 years (13%). Brain cancer accounted for the second largest proportion of PYLL (7,612 PYLL or 13%), followed by lung cancer (5,912 PYLL or 10%) and colorectal cancer (4523 PYLL or 8%). The PYLL in people who were both diagnosed and died before age 50 for all cancers was 59,123 in 2013.
PYLL is a measure that quantifies premature death and estimates the years that people could have lived if they had lived an average life span (using life expectancy tables). This measure is influenced by how common a cancer is, how fatal the cancer is, and the average age someone is when they are diagnosed. Although PYLL is usually calculated for all ages, this analysis only includes people who were diagnosed and died before age 50.
In Ontario, female breast cancer has a high PYLL because it is the most common cancer in people under age 50 (accounting for 1,901 new cases under age 50 in 2013), with poorer survival in younger than older women.[1] Lung cancer has a high PYLL because it is one of the most common cancers (282 new cases under age 50 in 2013) and has very poor survival because it is often diagnosed at advanced stages. Colorectal cancer is also a large contributor to PYLL in men and women under age 50 because it affects a large number of people (694 new cases under age 50 in 2013) and has moderate survival.[2]
Cancers that are less common, but frequently occur at young ages or have high mortality, may also have high PYLL. Brain cancer, for example, is relatively rare in the population as a whole, but it is highly fatal and is the second most common cancer in children under age 14. Therefore, it is responsible for a greater number of PYLL than several more common cancers that tend to develop in older people simply because its early onset means an even earlier premature death. Similarly, leukemia, soft tissue sarcomas, and cancers of the stomach and ovary are relatively rare, but rank among the leading contributors to PYLL from cancer under age 50 because their age of onset is early (particularly for leukemia and sarcomas) and/or survival is poor. Although liver cancer is relatively rare, it has recently become a bigger contributor to premature cancer death in Ontario because incidence rates continue to rise and survival from this cancer remains low.
The types of cancers responsible for the greatest PYLL in Ontarians under age 50 differ slightly from those for the entire Ontario population (i.e., Ontarians of all ages). PYLL in the entire population is mostly due to lung cancer and colorectal cancer, which rank first and second, respectively, followed by female breast cancer and pancreatic cancer (see “Lung cancer accounts for largest proportion of premature Ontario cancer deaths” [Dec. 2012 Ontario Cancer Fact]). The different PYLL rankings in people under age 50 reflect the higher proportion of premature deaths from cancers that have early onset and are highly fatal. For example, because pancreatic cancer tends to occur at older ages, its PYLL ranking drops when only death under age 50 is considered.
For cancers that occur more frequently in young adults and adolescents, such as brain cancer, the years of life lost and subsequent impact on society can often be substantial, despite relatively low incidence rates. More research is needed to better understand the risk factors associated with certain cancers that have early onset to help inform effective prevention efforts.