Abstract

Background

While impressive gains in childhood cancer survival have been reported both in Canada and internationally, it has been almost 15 years since the last comprehensive evaluation of Canadian data.

Data and methods

Data are from the population-based Canadian Cancer Registry, record-linked to the Canadian Vital Statistics Death database. Children aged 0 to 14 diagnosed with new primary malignant cancers from 1992 to 2017 in Canada except Quebec were included. Overall survival was measured using observed survival proportions (OSPs). Estimates for the 2013-to-2017 period were predicted using the period method; otherwise, the cohort method was used.

Results

For the 2013-to-2017 period, five-year OSPs were at least 90% for 10 of 24 individual cancer groups or subgroups reported. Survival was highest for thyroid carcinomas (100%) and Hodgkin lymphomas (99%) and lowest for other gliomas (42%). A significant increase in the five-year OSP from the 1992-to-1996 period (77%) to the 2013-to-2017 period (84%) was observed for all childhood cancers combined, but not since the 2003-to-2007 period. The greatest increase was for chronic myeloproliferative diseases (35.4 percentage points); for lymphoid leukemias, survival increased from 85% to 93%. Survival was relatively poor at baseline for hepatic tumours, malignant bone tumours, and soft tissue and other extraosseous sarcomas, and it remained virtually unchanged. Once children survived five years, the probability of surviving another five years exceeded 95% across most diagnoses.

Interpretation

Significant improvements in both short- and long-term paediatric cancer survival have been made in Canada since the early to mid-1990s. These findings are clinically meaningful and are likely to be reassuring to families.

Keywords

conditional survival, malignant neoplasms, paediatrics, population surveillance, prognosis, registries, survival analysis

DOI: https://www.doi.org/10.25318/82-003-x202100200001-eng

Findings

Each year in Canada, approximately 1,000 children aged 0 to 14 years are diagnosed with cancer, and 110 die from the disease. Worldwide, impressive gains in survival have been made over time. These advances can primarily be attributed to a deeper understanding of paediatric cancer biology, combined with successive, multi-institutional clinical trials. As a result, much of what is known about expected outcomes and risk factors is derived from clinical trials. Clinical trials provide excellent insight into how regimens perform within the context of close monitoring, strict application of eligibility criteria and adherence to protocol therapy. However, these results may not be generalizable to children not enrolled in clinical trials. For example, observational studies have suggested that children enrolled in clinical trials differ in terms of demographic characteristics and cancer-specific features from those not enrolled. Consequently, clinical trial results may not reflect outcomes at the population level. [Full article]

Authors

Larry F. Ellison (larry.ellison@canada.ca) is with the Centre for Population Health Data at Statistics Canada, Ottawa, Ontario. Lin Xie (lin.xie@canada.ca) is with the Centre for Surveillance and Applied Research, Public Health Agency of Canada, Ottawa, Ontario. Lillian Sung (lillian.sung@sickkids.ca) is with the Division of Haematology/Oncology, The Hospital for Sick Children, Toronto, Ontario.

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