BackgroundChildhood cancer survivors have been reported to be vulnerable to psychiatric morbidities and risky health behavior. Suicides, substance abuse, accidents, and violence as causes of death can be regarded as an extreme manifestation of risky health behavior. In the current study, the authors studied the risk of suicide and other risky health behavior–related deaths among childhood cancer patients in Denmark, Finland, and Sweden.MethodsUsing linkage between national cancer, population, and cause‐of‐death registries, the authors investigated the causes of death in 29,285 patients diagnosed with cancer before age 20 years between 1971 and 2009 compared with a cohort of 146,282 age‐matched, sex‐matched, and country‐matched population comparisons. Rate ratios (RRs) with 95% CIs were estimated using Poisson regression models, adjusting for demographic factors.ResultsThe overall risk of dying of a risky health behavior was found to be increased among childhood cancer patients (RR, 1.25; 95% CI, 1.06‐1.47) when compared with population comparisons. The elevated risk was statistically significant among patients with central nervous system tumors (RR, 1.49; 95% CI, 1.08‐2.05) and patients diagnosed at ages 5 to 9 years and 15 to 19 years (RR, 1.50 [95% CI, 1.01‐2.24] and RR, 1.31 [95% CI, 1.03‐1.67], respectively). The overall risk of suicide was found to be increased (RR, 1.37; 95% CI, 1.02‐1.83), and statistically significantly so when patients were diagnosed between ages 15 and 19 years (RR, 1.61; 95% CI, 1.09‐2.39).ConclusionsChildhood cancer patients appear to have an increased risk of risky health behavior–related causes of death compared with the general population. The results of the current study suggest the importance of integrating psychosocial support into the follow‐up care of these individuals.