Hypothalamic damage in pediatric brain tumor survivors: Effects of Radiotherapy and associations with Cognitive functioning

The hypothalamus is the key regulator of our body*s balance. Hypothalamic
dysfunction can occur in childhood brain tumor survivors (CBTS). Hypothalamic
dysfunction include pituitary (=endocrine) symptoms (pituitary dysfunction) and
non-pituitary symptoms (hyper/hypophagia, increased body mass index, behavioral
problems, sleep disorders, and temperature regulation disorders) and can
possible result in neurocognitive impairment. Hypothalamic syndrome is the most
severe form of hypothalamic dysfunction, with dysfunction of multiple functions
of the hypothalamus.
The symptoms of hypothalamic dysfunction may have a significant impact on
quality of life in CBTS and hypothalamic dysfunction can be caused by the tumor
itself, radiation therapy or surgery. However, the effect of radiotherapy on
the non-pituitary symptoms of hypothalamic dysfunction are still understudied.

Primary objective:
Development of a normal tissue complication probability (NTCP) model for
hypothalamic dysfunction (for severe hypothalamic dysfunction, named
hypothalamic syndrome) in childhood brain tumor survivors, incorporating
cranial radiation dose in addition to other relevant predictors (such as
surgery, age, location of the tumor, time since diagnosis)

Secondary objectives:
1. To investigate the prevalence and risk factors for the most severe form of
hypothalamic dysfunction (=hypothalamic syndrome as defined above) following
cranial radiation therapy
2. To investigate the prevalence and risk factors for non-pituitary signs or
symptoms of hypothalamic dysfunction (hyper/hypophagia, body mass index,
behavioral problems, sleep disorders, temperature regulation disorders)
following cranial radiation therapy
3. To investigate the prevalence and risk factors for pituitary dysfunction
following cranial radiation therapy
4. To investigate the prevalence and risk factors for neurocognitive
dysfunction following cranial radiation therapy
5. To evaluate the relationship between neurocognitive dysfunction,
hypothalamic dysfunction and other risk factors following cranial radiation
therapy

A cohort study will be performed at the Late effects (LATER), neuro-oncology
and endocrine outpatient clinic of the Princess Máxima Center for pediatric
oncology. Participation includes one visit to the out-patient clinic of the
Princess Máxima Center for determination of the hypothalamic and
neuropsychological outcomes and determinants.
After the visit, at home, a diary will be kept for monitoring of body
temperature. In case of suspicion of presence of a sleep disorder, additional
investigation on the type of sleep disorder will be offered including a sleep
diary and monitoring with an actigraph for seven days.

We anticipate that the burden and risks associated with participation will be
limited. This study will involve minors/incapacitated persons, since we want to
study the late effects of radiotherapy given in childhood with a follow-up of 5
years or more (and therefore also children will be included if they have not
reached the age of eighteen yet).
Possible benefits for the participants related to participation to this study
are the detection and recognition of hypothalamic dysfunction enabling
counselling and treatment. In addition, the participants will receive the
results of their neuropsychological assessment, which may reveal (new) insights
on the neuropsychological profile of the participants, also enabling
counselling and treatment.