Highlights
- The rate of new cases of cancer in children under 15 has increased over the past three decades in Ontario.
- The most common types of cancer among children in Ontario are leukemias, central nervous system cancers, lymphomas and soft tissue cancers.
- Cancer is more common in the very young (children ages zero to four) than in older children.
- Survival for childhood cancer is high and has increased over time.
From 1981 to 2013, the rate of childhood cancers increased significantly, by 0.6% per year, in Ontario. In 2013, almost 400 cases of cancer were diagnosed in the province in children under the age of 15. The most common major cancer types in children were leukemias, central nervous system (CNS) cancers, lymphomas and soft tissue cancers. These four cancer types accounted for almost three-quarters of all cancers diagnosed in children in Ontario.
The greatest increase from 1981 to 2013 among the major childhood cancer types was in CNS and soft tissue cancers (0.8 percent per year), although the rate of increase was similar for leukemias and lymphomas, as well.
From 2011 to 2013, cancer was more common in children under five (24.5 cases per 100,000) than in older children (14.1 cases per 100,000 in children ages five to nine; 17.3 per 100,000 in children ages 10 to 14). Of the ten [1] main childhood cancer types listed in the International Classification of Childhood Cancers, third edition (ICCC-3), only lymphomas and bone cancers were more common in children ages five to 14 than in children under five. Cancer was also more common in boys (19.4 cases per 100,000) than girls (17.7 cases per 100,000).
Although the rate of new cases has been increasing, survival for childhood cancers is high; 84 percent of children are expected to survive for at least five years after their diagnosis. Over the past three decades, this number has increased by approximately 20 percentage points.
Improvements in survival are most likely due to improvements in treatment. Childhood cancers differ from adult cancers. While childhood cancers have been increasing, the cancer rate among adults has been stable since 2001. This difference appears to be due to decreasing rates of lung, colorectal and prostate cancer, which are commonly diagnosed in adults but almost never occur in children. Children are more likely to develop blood and lymphatic cancers and cancers of the central nervous system. Cancers in children also tend to be more aggressive, grow more rapidly and are more likely to spread to other areas of the body. In addition, unlike with adult cancers, the ability to prevent childhood cancers is limited mainly because the causes of cancer in children are largely unknown.
While most children survive cancer, the survivors are at risk for long-term health problems as a result of their cancer and its treatment (e.g., second cancers, reduced fertility, psychological disorders). An estimated two-thirds of childhood cancer survivors have a chronic or long-term side effect from their cancer treatment. [2] Nevertheless, advancements in diagnostic technology and treatment continue to improve the prognosis and quality of life of these children.