The cumulative burden of self-reported, clinically relevant outcomes in long-term childhood cancer survivors and implications for survivorship care: A DCCSS LATER study

BACKGROUND: The aim of this study is to evaluate how cumulative burden of clinically relevant, self-reported outcomes in childhood cancer survivors (CCSs) compares to a sibling control group and to explore how the burden corresponds to levels of care proposed by existing risk stratifications.

METHODS: The authors invited 5925 5-year survivors from the Dutch Childhood Cancer Survivor Study (DCCSS LATER) cohort and their 1066 siblings to complete a questionnaire on health outcomes. Health outcomes were validated by self-reported medication use or medical record review. Missing data on clinically relevant outcomes in CCSs for whom no questionnaire data were available were imputed with predictive mean matching. We calculated the mean cumulative count (MCC) for clinically relevant outcomes. Furthermore, we calculated 30-year MCC for groups of CCSs based on primary cancer diagnosis and treatment, ranked 30-year MCC, and compared the ranking to levels of care according to existing risk stratifications.

RESULTS: At median 18.5 years after 5-year survival, 46% of CCSs had at least one clinically relevant outcome. CCSs experienced 2.8 times more health conditions than siblings (30-year MCC = 0.79; 95% confidence interval [CI], 0.74-0.85 vs. 30-year MCC = 0.29; 95% CI, 0.25-0.34). CCSs' burden of clinically relevant outcomes consisted mainly of endocrine and vascular conditions and varied by primary cancer type. The ranking of the 30-year MCC often did not correspond with levels of care in existing risk stratifications.

CONCLUSIONS: CCSs experience a high cumulative burden of clinically relevant outcomes that was not completely reflected by current risk stratifications. Choices for survivorship care should extend beyond primary tumor and treatment parameters, and should consider also including CCSs' current morbidity.