Risk of Hospitalization Remains High for Survivors of Childhood Leukemia

Risk of hospitalization for medical conditions are increased for survivors of childhood leukemia compared with matched cohorts without a cancer diagnosis in childhood. This study was published in the Journal of the National Cancer Institute.¹

Advances in the diagnosis and treatment of childhood leukemia over the last 50 years are associated with dramatically improved survival rates. Although increased risks of late adverse effects of treatment have been reported in some subgroups, a number of knowledge gaps exist regarding other subgroups with certain childhood leukemias. In addition, while several previous studies have identified increased risks of long-term morbidity using hospitalization as a surrogate measure, most did not identify the underlying causes for hospitalization.

This retrospective study is part of a large-scale population-based study being conducted in Nordic countries called the Adult Life after Childhood Cancer in Scandinavia (ALiCCS) Study. Patients with childhood leukemia — ie, a diagnosis of leukemia before age 20 — between 1970 and 2008 included in the cancer database were matched with a comparison cohort of 5 contemporary patients without a leukemia diagnosis in childhood. Follow-up was started 5 years after date of leukemia diagnosis in the cohort with leukemia and 5-years after that index date in each comparison group. Median follow-up was 16 years following cancer diagnosis.

Of the 4003 survivors of childhood leukemia included in the analysis, 84.7%, 9.7%, and 2.3% received a diagnosis of acute lymphoblastic leukemia (ALL), acute myeloid leukemia (AML), and chronic myeloid leukemia (CML), respectively. In the overall group of leukemia survivors, 37.2% were hospitalized for any disease during follow-up. Compared with the general population, CML survivors had the highest relative risk of hospitalization (relative risk [RR] = 4.51; 95% CI, 3.30-6.00). The corresponding relative risks of hospitalization were 3.09 (95% CI, 2.53-3.65) and 1.95 (95% CI 1.83-2.07) for survivors of AML and ALL, respectively. 

Furthermore, the relative risks for diseases of the circulatory system were 2.18 (95% CI, 1.80-2.64) in ALL survivors, 4.46 (3.03-6.56) in AML survivors, and 6.75 (3.37-13.51) in CML survivors compared with respective matched cohorts without cancer. In addition, the relative risk of a second cancer was approximately 4 times higher in the group of cancer survivors relative to the comparison cohorts.  Of note, the relative risks for hospitalization remained increased 20 years following cancer diagnosis.

Some of the limitations of this study include the absence of data on disease management in the primary care setting, and that treatment intensity was not considered in the analysis.²

Authors of an accompanying editorial wrote that “recognizing that common chronic health conditions associated with aging, such as hypertension or diabetes, accentuate the risk of heart disease in survivors, it is imperative that clinicians following long-term cancer survivors understand these risks and aggressively manage their comorbidities.”²

References

1. Sørensen GV, Winther JF, de Fine Licht S, et al. Long-term risk of hospitalization among five-year survivors of childhood leukemia in the Nordic countries [published online February 11, 2018].  Natl Cancer Inst. doi: 10.1093/jnci/djz016

2. Fidler-Benaoudia MM, Oeffinger KC. Childhood leukemia, late effects, and a person-centric model of follow-up. J Natl Cancer Inst.doi: 10.1093/jnci/djz018