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A developmental model for predicting declines in intellectual functioning
among pediatric patients with medulloblastoma
Shawna L
Palmer, Amar Gajjar, Wilburn E Reddick, John O Glass, Larry E Kun, Richard L
Heideman, Shenjie Wu, Xiong Xiaoping, Raymond K Mulhern
St. Jude Children's
Research Hospital, Memphis, TN
Objectives.
The aim of this study was to provide a predictive model of changes in
intellectual functioning for children treated with 35-40 Gy craniospinal
irradiation (CSI) for medulloblastoma (MB), with or without chemotherapy.
Methods.
120 patients with histologically proven MB, 3-21 years of age, were
treated between 1985-1999.
A patient was considered eligible for the present
study if they were treated with surgery, 35-40 Gy CSI, a posterior fossa boost
to 54 Gy, and had two or more psychological evaluations using the Wechsler
Intelligence Scales for Children (WISC) to obtain a measure of intellectual
functioning with an estimated full-scale IQ score (FSIQ).
Fifty patients were
treated outside the specified CSI dose, 14 patients had single evaluations and 3
patients were too young to take the WISC, while 5 were evaluated using an adult
version of the Wechsler scales.
These exclusions resulted in 48 participating
patients (30 M: 18 F) with a total of 180 psychological evaluations (Mean=3.86
exams/patient).
Results.
Patients had a mean age at CSI of 8.3 years and were
0-13.87 years from CSI.
Using a longitudinal growth curve model, the pattern of
FSIQ scores was found to be a non-linear function of time since start of CSI,
for which the intercept and slope depended upon the age of the patient at CSI
(p<.0001).
Younger age at CSI was associated with lower intercept, steeper
declines in FSIQ and a longer time until reaching a plateau (Table 1).
Conclusions.
With appropriate understanding of this models limitations, and the
patients baseline evaluation score, clinicians will be able to use the patients
age at CSI to predict changes in intellectual functioning over time.
The results
allow families to be better informed of potential late-effects and emphasize the
need for early intervention, especially among very young patients.
Influence
of age at CSI on predicted intellectual function over time since CSI.
|
Age at CSI
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Intercept
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Average
loss of IQ points
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Time
to plateau*
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3
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94.44
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30
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12
|
|
6
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95.23
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18
|
9
|
|
9
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96.02
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8
|
6
|
|
12
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96.82
|
2.5
|
3.5
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* years.
© Copyright 2002 American Society of Clinical Oncology
Source:
http://www.asco.org/ac/1,1003,_12-002324-00_18-002002-00_19-00284-00_29-00A-00_42-00ONeill-00_43-00-00_44-00-00_45-00
Author-00_46-00Title-00_47-00Title-00_48-00and-00_49-00and,00.asp?cat=CNS+Tumors&parent=CENTRAL+NERVOUS+SYSTEM+TUMORS
&returnpid=2323
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