Trends in Long-Term Excess Mortality Risk and Survival among Childhood and Adolescent Cancer Survivors in the United...

Childhood and adolescent cancer survivors represent a growing population whose outcomes reflect both advances in therapy and late effects of treatment. We quantified trends in long-term excess mortality risk and survival using standardized mortality ratios (SMR) and relative survival, respectively.

Using the Surveillance, Epidemiology, and End Results data, we assessed 5-year relative survival and 5-year relative survival, conditional on surviving 5 years, by period of diagnosis (1975-1979 vs. 2016-2020, and 1975-1979 vs. 2011-2015, respectively). Trends were quantified by year at diagnosis using the joinpoint survival model. SMRs were estimated by 5-year time-since-diagnosis intervals and calendar-year diagnosis periods.

Between 1975 and 2020, there were improvements in 5-year relative survival, with acute myeloid leukemia (AML) and non-Hodgkin lymphoma (NHL) having the greatest survival gains. For osteosarcoma, central nervous system tumors, and Wilms tumor, 5-year relative survival plateaued in recent decades. Five-year relative survival, conditional on surviving 5 years, was >90% for survivors diagnosed between 2011 and 2015 for all cancer sites analyzed. Overall, SMRs declined with increasing time since diagnosis. Excess mortality risk also decreased over calendar-year diagnosis periods, particularly during the first 5 years since diagnosis, for cancers such as lymphoid leukemia, AML, Hodgkin lymphoma, and NHL.

Overall, we observed considerable improvements in 5-year relative survival and declines in excess mortality risk over time.

These findings reflect advances in treatment and survivorship care. Long-term follow-up and continued research efforts are needed to understand long-term mortality risks within an evolving treatment landscape and to achieve further progress. See related In the Spotlight, p. 791.