Medical assessment of adverse health outcomes in Dutch childhood cancer survivors; a nationwide project; SKION LATER Q2008 onderzoek:
Adult growth hormone deficiency in childhood cancer survivors

Growth hormone deficiency (GHD) is the most common long term complication of
patients who received cranial radiotherapy (RT). The radiation-induced damage
to the hypothalamic-pituitary axis is both dose and time dependent and may only
become apparent after a latency of many years until in advanced adulthood (1).
GHD has several unfavorable effects on health status in children as well as in
adults. Children with GHD show attenuated linear growth or blunting of the
pubertal growth spurt. GHD in adults is associated with decreased quality of
life (2) , fatigue, impaired cognitive functioning, decreased mass of muscle
and bone, components of the metabolic syndrome and (most likely) cardiovascular
disease. Symptoms of GHD can be reversed by growth hormone substitution therapy
(3).
The gold standard for the diagnosis of GHD is the insulin tolerance test, which
is time consuming, inconvenient to the patient and contraindicated in certain
instances. In such cases an arginine stimulation test is recommended.
Traditionally, screening for GHD is performed by measurement of IGF-1 and
reduced concentrations of IGF-1 levels are highly suggestive of GHD. But a
normal IGF-1 does not rule out GHD, especially after cranial irradiation and in
patients with characteristics of the metabolic syndrome (4). The latter is very
common in childhood cancer survivors, and contributes to the low sensitivity of
IGF-1 to detect patients with GHD. Measurement of free/bioactive IGF-1 may
circumvent the shortcomings of the (total) IGF-1 assay, but its diagnostic
accuracy for this patient group remains to be proven (5).
Identification of patients with GHD is essential because this offers an
evidence based treatment option, with among other effects, an improvement in
quality of life. This study examines the best diagnostic strategy for the
identification of GHD in childhood cancer survivors at risk for development of
GHD.

To assess the diagnostic accuracy of total and free IGF-1 concentrations by
comparing it to the gold standard for detection of growth hormone deficiency in
adults, i.e. the insulin tolerance test, in subgroups of patients at risk for
growth hormone deficiency and the distribution of total and bioactive IGF-I.

This study with cross sectional design will consist of an anamnesis and
physical exam, for a subpopulation of 160 survivors a ITT, and a venapuncture.
for a substantial part of the population, these tests will be part of regular
patient follow up as defined by the guidelines for screening for late toxicity
in CCS. Data will be collected anonymously in a central database.

the largest part of the participants (n=1300) / controles, will get a
outpatient visit and venapuncture as part of their regular follow up based on
screening guidelines for CCS. The part of the study for the radiotherapy
patients (n=160,120 minutes), the outpatient visit and venapuncture is part of
the regular follow up based on screening guidelines for CCS.