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Children who survive leukaemia have a higher risk of hospitalisation well into adulthood

A Scandinavian research group is the first in the world to carry out an in-depth study of delayed complications following three types of child leukaemia.

Researchers from Aarhus University Hospital and Aarhus University have headed a major Scandinavian study which shows that children and young people who have survived for at least five years after having leukaemia have an overall risk of being hospitalised that is twice as high as it is for other children and young people, and that the increased risk of hospitalisation continues well into their adult lives. The results have just been published in the American Journal of the National Cancer Institute (JNCI).

Intensified treatment over the last few decades has led to a significant improvement in survival rates for children with leukaemia. For the most frequently seen type of leukaemia, acute lymphoblastic leukaemia (ALL), the figure for long-term survival is around ninety per cent. Treatment can be intensive and is associated with side effects, some of which are serious and might first appear many years after the treatment. Being able to uncover any pattern of complications is essential to enabling adjustments to the treatment and follow-up.

There are different sub-types of leukaemia and these are all treated differently, so they can therefore have different delayed complication patterns. For the first time, the researchers have carried out an in-depth study of the risk of hospitalisation for survivors of ALL, which is the most commonly occurring type of leukaemia in children, acute myeloid leukaemia (AML), the next most common, and chronic myelogenous leukaemia (CML), which is very rare.

“We found that the type of leukaemia had significance for the delayed complications. For survivors of both the CML and AML types, the overall risk of hospitalisation was higher than it was for the ALL survivors. This could be due to bone marrow transplants having been used more often in cases of AML and CML compared to ALL,” says medical doctor and PhD student Gitte Vrelits Sørensen.

With the help of the unique Scandinavian registers, the researchers have been able to more or less create a complete overview of occurrences of diseases that are serious enough to require hospitalisation in survivors of childhood leukaemia. The researchers separated the causes of the hospitalisations into a total of 120 disease categories. The risk of hospitalisation among the former child leukaemia patients was subsequently compared with the risk of hospitalisation among the almost 130,000 children and young people without a cancer diagnosis. 

The researchers found that ALL survivors had a particularly high risk of brain tumours, epilepsy and reduced function of the pituitary gland, among other things. In the case of AML survivors, they found a high risk of e.g. heart failure and glaucoma (cataracts) and for CML survivors they found a high risk of diseases such as glaucoma, pneumonia and also diseases of the bones and joints.

“It’s important to point out that although leukaemia survivors generally have a high relative risk of contracting many diseases compared to the population in general, the diseases are fortunately rare, and the absolute risk is therefore generally low – also for leukaemia survivors. It’s also important to emphasise that the majority of children who are diagnosed with leukaemia today survive the disease without serious delayed complications.”

With this study, researchers have provided a detailed overview of the long-term risk of hospitalisation among child leukaemia survivors. The researchers followed a total of 4,003 five-year survivors who had been diagnosed with leukaemia before the age of twenty between 1970 and 2008 in Denmark, Sweden, Finland and Iceland.

“The international collaboration and detailed national registers together with equal access to the healthcare system in the Scandinavian countries made it possible to follow a very large group of child leukaemia survivors over a period of many years, which in turn provides high quality data,” says Gitte Vrelits Sørensen.

The study contributes with new knowledge for both long-term survivors and healthcare professionals, and this information will be useful in connection with the preparation of long-term follow-up guidelines for this large and growing group of childhood cancer survivors. The researchers next step will be to combine this information with detailed treatment information.

“For example, we are in the process of carrying out a large study for ALL survivors where we will be able to see how the primary cancer treatment (including stem cell treatment and radiotherapy) and relapses of leukaemia affect the risk of delayed complications. This means we’ll be able to determine whether there are some groups of childhood leukaemia survivors who should be followed even more closely, and other groups that perhaps may not need to be followed so closely," says Gitte Vrelits Sørensen.

About the study:

  • Type of study: Cohort study based on the Danish, Swedish, Icelandic and Finnish health registers.
  • Partners: In addition to the Department of Children and Young People, Aarhus University Hospital and the Department of Clinical Medicine, Aarhus University; The Danish Cancer Society; Skåne University Hospital, The Institute of Clinical Sciences, Lund University, Sweden; The Finnish Cancer Register, Helsinki, Finland; The Icelandic Cancer Registry, Reykjavik, Iceland; and the Department of Epidemiology, Rollins School of Public Health, Emory University, USA.   
  • Funding: The Child Cancer Foundation Denmark, Aarhus University, The Danish Cancer Society and a Danish foundation – Grosserer M. Brogaard & hustrus Mindefond.  
  • Read the scientific article: https://doi.org/10.1093/jnci/djz016


MD, PhD student Gitte Vrelits Sørensen
Department of Clinical Medicine, Aarhus University, Department of Children and Young People, Aarhus University Hospital.
Email: gitte@clin.au.dk
Tel.: (+45) 2043 8085

Consultant, Professor Henrik Hasle
Department of Clinical Medicine, Department of Children and Young People, Aarhus University Hospital.
Email: hasle@dadlnet.dk
Tel.: (+45) 4158 7114