Overweight is relatively common after treatment for childhood cancer. Weight gain can be caused by treatment or psychosocial factors, but also by the location of the tumor. Weight problems are more common in children whose tumor is located in or near the hypothalamus, an area in the brain that regulates hormones and appetite.
Long-term study
To investigate whether children with other brain tumors are also at higher risk of being overweight, scientists at the Princess Máxima Center led by pediatric endocrinologist and researcher Hanneke van Santen, studied some 700 children who were diagnosed with a brain tumor between 2002 and 2012. They looked at weight and hormone levels before, during and after treatment. The research, conducted in collaboration with the Wilhelmina Children's Hospital and other academic children's hospitals in the Netherlands, was published in the Journal of Clinical Oncology.
The scientists found that one third of the children with a brain tumor had severe weight gain, overweight or obesity. At follow-up, about 29 percent of survivors aged 4-20 years were overweight or obese, compared with 13 percent of children and adolescents in general. If children were already overweight at diagnosis, they were more likely to be overweight or obese at follow-up. Children with a low-grade brain tumor or those who already had another hormone problem had a higher chance of being overweight.
Relationship between hormones and obesity
Hanneke van Santen: ‘We found that overweight children more frequently had hormone loss than other children with a brain tumor. This overweight was present even when the hormone failure had been treated successfully. This could indicate weight gain due to an underlying hypothalamic problem.’
The hypothalamus is an area of the brain that can be seen as the control center for hormones. These play an important role in the energy balance of the body – burning of energy and storage of energy in muscle or fat mass. In addition to hormone control, the hypothalamus also plays an important role in regulating appetite. The new study adds to the understanding of the link between hormone regulation and obesity in children with brain tumors.
Better monitoring
Future research is needed to find treatment for obesity caused by problems with the hypothalamus. It is also necessary to further investigate what causes overweight in children whose tumor is not near the hypothalamus. The researchers recommend that children with brain tumors who gain weight quickly or are overweight should be better monitored for hormonal failure to prevent overweight and to treat problems with hormone levels sooner.
Jiska van Schaik, medical researcher at the Princess Máxima Center and co-author of the study: 'The study gives us a better picture of how often and to what extent overweight occurs in children with brain tumors, and what the risk factors are. For some children, we can start paying more attention to nutrition and exercise. In the future we can hopefully reduce late effects due to obesity, such as an increased risk of cardiovascular disease.’