Discussion
The present study examines psychosocial and executive functioning
outcomes in a large cohort of pediatric brain tumor survivors at an
average of 3.84 years post-PRT. Mean scores were not significantly
different from normative expectation for psychosocial and executive
functioning at follow-up. However, rates of impairment in social
withdrawal, activities of daily living, and metacognitive executive
functioning skills were markedly higher than would be expected in the
general population. These results are largely consistent with the
growing body of literature among pediatric brain tumor survivors
post-PRT that report sample means in the normal range for many aspects
of emotional and behavioral functioning whereas problems are often
reported at a higher level with social and executive
functioning.14
Favorably, the current findings revealed significantly less behavior
problems (hyperactivity, aggression) compared to normative expectations
consistent with previous studies.20-22 Problems with
depression or anxiety were not identified, an important finding with
regard to quality of life. However, a relatively large proportion of
patients (12.5%) was rated as having problems with somatization and
were viewed by their parents as having more physical
complaints/discomforts; 42-43 not surprising given the
complex medical history of brain tumor survivors.
A large proportion of survivors were rated as having impairment in
social withdrawal (≈18%) (a tendency to evade others to avoid social
contact) 42-43 although their social skills were
within the normal range with a low rate of impairment, suggesting
survivors have the skills necessary for interacting successfully with
peers and adults. This finding is consistent with prior literature on
conventional post-radiation outcomes reflecting greater social
withdrawal,17 isolation,2,6,23,25and lower acceptance,2,26 but lacking deficits in
social cognition skills (knowledge about how to appropriately interact).
Reduced prosocial skills (complimenting others, offering help) were
observed in a post-PRT study14 reflecting the need for
further exploration of this specific aspect of socialization.
The higher rate of challenges with activities of daily living (15%) is
consistent with prior research that identified greater adaptive skills
impairment among a more homogenous sample of youth 5 years post-PRT,
particularly in the domains of practical and social
skills.12 While the mean for our total sample did not
exceed normative expectation, the rate of impairment in activities of
daily living and the recent finding in the literature warrant continued
attention to the development of these skills. Metacognitive executive
functioning was the area of greatest concern reported by parents in this
study, consistent with the literature.19,34-35Significantly more survivors were rated as having problems with aspects
of metacognitive executive functioning skills (up to 25%), which
includes the ability to take initiative, sustain working memory (e.g.,
capacity to hold and “work on” information in mind to complete an
activity), and plan and organize tasks.
Previous research has indicated an association between problems with
psychosocial and executive functioning and time interval following
PRT.14,46 However, this finding was surprisingly not
revealed in this sample. In fact, most demographic and treatment-related
factors examined did not significantly impact psychosocial and executive
functioning outcomes in this sample, including gender, race, SES, tumor
location, radiation field, history of surgery, or chemotherapy. While
some studies have identified relationships between PRT treatment
variables (hydrocephalus, time since treatment) and social
outcomes,14 these patterns are not universal.
Age at baseline and histology were the only factors that had significant
relationships with outcomes; younger ages at baseline and those
diagnosed with ependymoma (youngest histology group at baseline) had
more behavior problems and older ages at baseline had more problems with
adaptive skills at follow-up. Prior research has noted greater emotional
and behavioral difficulty associated with younger age at
treatment..22,37 For older ages, the
inability to meet increasing expectations to carry out tasks with
greater independence with advancing age may reflect the high rate of
metacognitive executive challenges found in this sample.
Psychosocial and executive functioning outcomes should be understood in
the context of various environmental and situational factors (extended
absences from school, reduced opportunities for peer interactions,
development of everyday living skills). The impact of tumor-related
symptoms prior to diagnosis (e.g., tailored treatment interventions,
premorbid developmental and genetic patterns) also need to be
considered. Similarly, the major role of parents and health care
professionals during their treatment course may contribute to deviations
in typical developmental trajectories that may not be accounted for by
late effects alone. Taken together, these factors may contribute to, but
do not fully account for,27 the disruption of normal
development of psychosocial and executive functioning.
These findings highlight both the importance of routine targeted
screening (rating scales/questionnaires) for emerging challenges in
psychosocial and executive functioning in pediatric brain tumor
survivors treated with PRT, as well as the need for targeted proactive
interventions. Such interventions could target the development of social
initiative and participation, independence in adaptive skills, and
metacognitive executive functioning skills. For example, interventions
that provide increased opportunities for positive social interactions
with peers in the context of adult-facilitated support appropriate for
age may minimize social withdrawal and maximize social initiation and
engagement. Patients may benefit from explicit instruction or coaching
in executive functioning that teaches them age-appropriate strategies to
plan, organize, set goals, prioritize, multi-task, and be a self-starter
and independently problem solve. Cognitive
remediation,47-49 cognitive-behavioral
therapy,46 social skill
programming,50-51 and
psychopharmacology52-53 each have been shown to be
effective for pediatric brain tumor survivors. Methylphenidate may be
beneficial for some patients following PRT as long-term improvements in
both social functioning and withdrawal have been
reported.52
A strength of the current study is the large cohort of pediatric brain
tumor survivors in the sample. While these results contribute to the
growing knowledge of psychosocial and executive functioning outcomes of
pediatric brain tumor survivors treated with PRT, several limitations of
the present study should be noted. First, the cross-sectional study
design precludes direct analysis of change over time. Longitudinal
studies are needed to examine change in order to identify the emergence
and trajectory of psychosocial and executive functioning challenges and
to guide targeted screening and proactive intervention efforts. Second,
the mean follow-up time interval in this study is relatively short. Late
effects of radiation therapy have been well
established29 and psychosocial and executive
functioning challenges may emerge later than the mean time interval
observed. However, the time interval since PRT and follow-up was not
correlated with the primary outcome measures in the present study.
Third, the sample was
predominantly White and of relatively high SES, with an estimated median
income higher than that of the United States.
This homogenous profile may not
be representative of patients who receive similar treatment at other
medical centers and the results need to viewed in this context. In
addition, patients who received follow-up assessment may have parents
with greater concerns regarding their child’s outcome, possibly
resulting in a sample that is not representative of all pediatric brain
tumor survivors. Finally, the current findings are based only on parent
rating scales, which are subject to rater bias and can reflect parents’
impressions.
In summary, although psychosocial
and executive functioning were, on average, in the normal range in this
large cohort of pediatric brain tumor survivors, significant problems
were found with social withdrawal, activities of daily living, and
metacognitive executive functioning skills. However, no significant
problems were evident with depression, anxiety, inattention,
hyperactivity, conduct, behavioral dysregulation or overall adaptive
skills. Age at baseline was related to problem behaviors and adaptive
skills: Younger patients tended to have problem behaviors at follow-up
whereas older patients struggled with independent adaptive or everyday
living skills. Neither time interval since PRT nor radiation field were
related to outcome. Future research will examine a longer follow-up
interval to better determine the risk of late effects of PRT.
Conflict of Interest: No actual or potential conflicts of
interest exist for any author. Torunn Yock receives in kind research
support from MIM software.
Acknowledgments: The authors thank the MGH Francis Burr Proton
Center pediatric patients and their families for participation in this
study. This project was supported in part by the Federal Share of
program income earned by the Massachusetts General Hospital on C06
CA059267 Proton Therapy Research and Treatment Center to Margaret
Pulsifer and is registered at NCT01180881 ClinicalTrials.gov.