Radiation dosimetry predicts IQ after conformal radiation therapy in pediatric patients with localized ependymoma

Neurocognitive Effects and Necrosis in Childhood Cancer Survivors Treated With Radiation Therapy: A PENTEC Comprehensive Review

PURPOSE

A PENTEC review of childhood cancer survivors who received brain radiation therapy (RT) was performed to develop models that aid in developing dose constraints for RT-associated central nervous system (CNS) morbidities.

METHODS AND MATERIALS

A comprehensive literature search, through the PENTEC initiative, was performed to identify published data pertaining to 6 specific CNS toxicities in children treated with brain RT. Treatment and outcome data on survivors were extracted and used to generate normal tissue complication probability (NTCP) models.

RESULTS

The search identified investigations pertaining to 2 of the 6 predefined CNS outcomes: neurocognition and brain necrosis. For neurocognition, models for 2 post-RT outcomes were developed to (1) calculate the risk for a below-average intelligence quotient (IQ) (IQ <85) and (2) estimate the expected IQ value. The models suggest that there is a 5% risk of a subsequent IQ <85 when 10%, 20%, 50%, or 100% of the brain is irradiated to 35.7, 29.1, 22.2, or 18.1 Gy, respectively (all at 2 Gy/fraction and without methotrexate). Methotrexate (MTX) increased the risk for an IQ <85 similar to a generalized uniform brain dose of 5.9 Gy. The model for predicting expected IQ also includes the effect of dose, age, and MTX. Each of these factors has an independent, but probably cumulative effect on IQ. The necrosis model estimates a 5% risk of necrosis for children after 59.8 Gy or 63.6 Gy (2 Gy/fraction) to any part of the brain if delivered as primary RT or reirradiation, respectively.

CONCLUSIONS

This PENTEC comprehensive review establishes objective relationships between patient age, RT dose, RT volume, and MTX to subsequent risks of neurocognitive injury and necrosis. A lack of consistent RT data and outcome reporting in the published literature hindered investigation of the other predefined CNS morbidity endpoints.

Management of first recurrence or progression of craniopharyngioma after resection alone: A systematic review and individual-participant data meta-analysis

The initial management of craniopharyngioma is generally either gross total resection (GTR) or subtotal resection (STR) with adjuvant radiotherapy (RT). However, the optimal management strategy for recurrent/progressive craniopharyngioma remains unclear. In this systematic review and individual participant data meta-analysis, we aimed to compare the outcomes of surgery and/or RT for the first recurrence/progression of craniopharyngioma after resection alone. The exposure was the treatment that was administered for the first recurrence/progression, and the outcomes were tumor regrowth and overall survival (OS). Subgroup analyses were performed by age at the treatment for the first recurrence/progression (<18 or ≥ 18 years old), duration between the first treatment and the first recurrence/progression (<2 or ≥ 2 years), and the initial treatment that was administered (STR or GTR). Of the 2932 studies screened, 11 studies reporting a total of 80 patients were included. Across almost all subgroups, patients who received RT for the first recurrence/progression had a significantly lower risk of tumor regrowth than those who did not, regardless of whether surgery was performed and the extent of resection. There was no significant association between the treatment administered for the first recurrence/progression and OS, except for patients with a recurrence/progression < 2 years after the first treatment, where GTR was associated with a higher risk of mortality. For patients with the first recurrence/progression of craniopharyngioma after resection alone, RT should be considered for better local control. In cases where RT is not administered, GTR is preferred over STR provided it can be safely performed, for improved local control.

Microstructural Cerebellar Injury Independently Associated With Processing Speed in Adult Patients With Primary Brain Tumors: Implications for Cognitive Preservation

PURPOSE

The cerebellum's role in posttreatment neurocognitive decline is unexplored. This study investigated associations between cerebellar microstructural integrity using quantitative neuroimaging biomarkers and neurocognition among patients with primary brain tumors receiving partial-brain radiation therapy (RT).

METHODS AND MATERIALS

In a prospective trial, 65 patients underwent volumetric brain magnetic resonance imaging, diffusion tensor imaging, and memory, executive function, language, attention, and processing speed (PS) assessment before RT and at 3, 6, and 12 months after RT. Delis-Kaplan Executive Function System-Trail Making (D-KEFS-TM) visual scanning and number and letter sequencing and Wechsler Adult Intelligence Scale, Fourth Edition, coding were used to evaluate PS. The cerebellar cortex and white matter (WM) and supratentorial structures subserving the previously mentioned cognitive domains were autosegmented. Volume was measured within each structure at each time point along with diffusion biomarkers (fractional anisotropy and mean diffusivity) in WM structures. Linear mixed-effects models assessed cerebellar biomarkers as predictors of neurocognitive scores. If associated, cerebellar biomarkers were evaluated as independent predictors of cognitive scores controlling for domain-specific supratentorial biomarkers.

RESULTS

Left (P = .04) and right (P < .001) cerebellar WM volume declined significantly over time. Cerebellar biomarkers were not associated with memory, executive function, or language. Smaller left cerebellar cortex volume was associated with worse D-KEFS-TM number (P = .01) and letter (P = .01) sequencing scores. A smaller right cerebellar cortex volume correlated with worse D-KEFS-TM visual scanning (P = .02) and number (P = .03) and letter (P = .02) sequencing scores. Greater right cerebellar WM mean diffusivity, indicating WM injury, was associated with worse D-KEFS-TM visual scanning performance (P = .03). Associations remained significant after controlling for corpus callosum and intrahemispheric WM injury biomarkers.

CONCLUSIONS

Injury to the cerebellum as measured with quantitative biomarkers correlates with worse post-RT PS, independent of corpus callosum and intrahemispheric WM damage. Efforts to preserve cerebellar integrity may preserve PS.

Proton Therapy for Advanced Juvenile Nasopharyngeal Angiofibroma

PURPOSE

To provide the first report on proton radiotherapy (PRT) in the management of advanced nasopharyngeal angiofibroma (JNA) and evaluate potential benefits compared to conformal photon therapy (XRT).

METHODS

We retrospectively reviewed 10 consecutive patients undergoing PRT for advanced JNA in a definitive or postoperative setting with a relative biological effectiveness weighted dose of 45 Gy in 25 fractions between 2012 and 2022 at the Heidelberg Ion Beam Therapy Center. Furthermore, dosimetric comparisons and risk estimations for short- and long-term radiation-induced complications between PRT plans and helical XRT plans were conducted.

RESULTS

PRT was well tolerated, with only low-grade acute toxicities (CTCAE I-II) being reported. The local control rate was 100% after a median follow-up of 27.0 (interquartile range 13.3-58.0) months. PRT resulted in considerable tumor shrinkage, leading to complete remission in five patients and bearing the potential to provide partial or complete symptom relief. Favorable dosimetric outcomes in critical brain substructures by the use of PRT translated into reduced estimated risks for neurocognitive impairment and radiation-induced CNS malignancies compared to XRT.

CONCLUSIONS

PRT is an effective treatment option for advanced JNA with minimal acute morbidity and the potential for reduced radiation-induced long-term complications.

Neurocognitive outcomes in pediatric brain tumors after treatment with proton versus photon radiation: a systematic review and meta-analysis

BACKGROUND

Advances in cancer treatments, particularly the development of radiation therapy, have led to improvements in survival outcomes in children with brain tumors. However, radiation therapy is associated with significant long-term neurocognitive morbidity. The present systematic review and meta-analysis aimed to compare the neurocognitive outcomes of children and adolescents with brain tumors treated with photon radiation (XRT) or proton therapy (PBRT).

METHODS

A systematic search was conducted (PubMed, Embase, Cochrane, and Web of Science from inception until 02/01/2022) for studies comparing the neurocognitive outcomes of children and adolescents with brain tumors treated with XRT vs. PBRT. The pooled mean differences (expressed as Z scores) were calculated using a random effects method for those endpoints analyzed by a minimum of three studies.

RESULTS

Totally 10 studies (n = 630 patients, average age range: 1-20 years) met the inclusion criteria. Patients who had received PBRT achieved significantly higher scores (difference in Z scores ranging from 0.29-0.75, all P < 0.05 and significant in sensitivity analyses) after treatment than those who had received XRT for most analyzed neurocognitive outcomes (i.e., intelligence quotient, verbal comprehension and perceptual reasoning indices, visual motor integration, and verbal memory). No robust significant differences (P > 0.05 in main analyses or sensitivity analyses) were found for nonverbal memory, verbal working memory and working memory index, processing speed index, or focused attention.

CONCLUSIONS

Pediatric brain tumor patients who receive PBRT achieve significantly higher scores on most neurocognitive outcomes than those who receive XRT. Larger studies with long-term follow-ups are needed to confirm these results.

The Current State of Radiotherapy for Pediatric Brain Tumors: An Overview of Post-Radiotherapy Neurocognitive Decline and Outcomes

Tumors of the central nervous system are the most common solid malignancies diagnosed in children. While common, they are also found to have some of the lowest survival rates of all malignancies. Treatment of childhood brain tumors often consists of operative gross total resection with adjuvant chemotherapy or radiotherapy. The current body of literature is largely inconclusive regarding the overall benefit of adjuvant chemo- or radiotherapy. However, it is known that both are associated with conditions that lower the quality of life in children who undergo those treatments. Chemotherapy is often associated with nausea, emesis, significant fatigue, immunosuppression, and alopecia. While radiotherapy can be effective for achieving local control, it is associated with late effects such as endocrine dysfunction, secondary malignancy, and neurocognitive decline. Advancements in radiotherapy grant both an increase in lifetime survival and an increased lifetime for survivors to contend with these late effects. In this review, the authors examined all the published literature, analyzing the results of clinical trials, case series, and technical notes on patients undergoing radiotherapy for the treatment of tumors of the central nervous system with a focus on neurocognitive decline and survival outcomes.

Neurocognitive Outcomes in Pediatric Patients Following Brain Irradiation

Advanced radiation techniques can reduce the severity of neurocognitive sequelae in young brain tumor patients. In the present analysis, we sought to compare neurocognitive outcomes after proton irradiation with patients who underwent photon radiotherapy (RT) and surgery. Neurocognitive outcomes were evaluated in 103 pediatric brain tumor patients (proton RT n = 26, photon RT n = 30, surgery n = 47) before and after treatment. Comparison of neurocognitive outcomes following different treatment modalities were analyzed over four years after treatment completion. Longitudinal analyses included 42 months of follow-up after proton RT and 55 months after photon RT and surgery. Neurocognitive assessment included standardized tests examining seven domains. A comparison of neurocognitive outcomes after RT (proton and photon with >90% additional surgery) and surgery showed no significant differences in any neurocognitive domain. Neurocognitive functioning tests after proton RT failed to identify alterations compared to baseline testing. Long-term follow up over four years after photon RT showed a decrease in non-verbal intelligence (-9.6%; p = 0.01) and visuospatial construction (-14.9%; p = 0.02). After surgery, there was a decline in non-verbal intelligence (-10.7%; p = 0.01) and processing speed (14.9%; p = 0.002). Differences in neurocognitive outcomes between RT and surgical cohorts in direct intermodal comparison at long-term follow-up were not identified in our study, suggesting that modern radiation therapy does not affect cognition as much as in the past. There were no alterations in long-term neurocognitive abilities after proton RT, whereas decline of processing speed, non-verbal intelligence, and visuospatial abilities were observed after both photon RT and surgery. Domains dependent on intact white matter structures appear particularly vulnerable to brain tumor treatment irrespective of treatment approach.

Intellectual functioning among case-matched cohorts of children treated with proton or photon radiation for standard-risk medulloblastoma

BACKGROUND

Proton therapy may reduce cognitive deficits after radiotherapy among brain tumor survivors, although current data are limited to retrospective comparisons between historical cohorts. The authors compared intelligence quotient scores within a case-matched cohort of children with medulloblastoma treated with proton radiation (PRT) or photon radiation (XRT) over the same time period.

METHODS

Among 88 consecutive patients with standard-risk medulloblastoma treated with PRT or XRT at 2 institutions from 2000 to 2009, 50 were matched 1:1 (25 with PRT and 25 with XRT) according to age, gender, date of diagnosis, histology, radiation boost, and craniospinal irradiation dose. One-way analyses of variance were performed to compare the Full-Scale Intelligence Quotient (FSIQ) and associated index scores between the 2 cohorts.

RESULTS

Neurocognitive data were available for 37 survivors (17 with PRT and 20 with XRT) from the matched cohort. The mean age was 8.5 years (SD, 4.14 years). The median follow-up was 5.3 years (range, 1.0-11.4 years) and 4.6 years (range, 1.1-11.2 years) for the PRT and XRT cohorts, respectively (P = .193). Patients treated with PRT had significantly higher mean FSIQ (99.6 vs 86.2; P = .021), verbal (105.2 vs 88.6; P = .010), and nonverbal scores (103.1 vs 88.9; P = .011) than the XRT-treated cohort. Differences in processing speed (82.9 vs 77.2; P = .331) and working memory (97.0 vs 92.7; P = .388) were not statistically significant.

CONCLUSIONS

Radiotherapy-associated cognitive effects appear to be more attenuated after proton therapy. Comprehensive prospective studies are needed to appropriately evaluate the neurocognitive advantages of proton therapy.

Radiation therapy for infants with cancer

The clinical outcomes for infants with malignant tumors are often worse than older children due to a combination of more biologically aggressive disease in some cases, and increased toxicity-or deintensification of therapies due to concern for toxicity-in others. Especially in infants and very young children, finding the appropriate balance between maximizing treatment efficacy while minimizing toxicity-in particular late side effects-is crucial. We review here the management of malignant tumors in infants and very young children, focusing on central nervous system (CNS) malignancies and rhabdomyosarcoma.

The ROCOCO performance scoring system translates dosimetric differences into clinically relevant endpoints: Comparing IMPT to VMAT in an example pilocytic astrocytoma dataset

BACKGROUND AND PURPOSE

Proton therapy is expected to outperform photon-based treatment regarding organs at risk (OAR) sparing but to date there is no method to practically measure clinical benefit. Here, we introduce the novel ROCOCO Performance Scoring System (RPSS) translating dose differences into clinically relevant endpoints and apply this to a treatment plan comparison of volumetric modulated arc therapy (VMAT) and intensity modulated proton therapy (IMPT) in 20 pilocytic astrocytoma patients.

MATERIAL AND METHODS

The RPSS was developed on the basis of expert-based weighting factors and toxicity scores per OAR. The imaging datasets of 20 pilocytic astrocytoma patients having undergone radiotherapy were included in this in silico dosimetric comparison trial as proof of principle. For each of these patients, treatment plans to a total dose of 54 Gy (RBE) were generated for VMAT and IMPT and these were compared regarding radiation dose to the clinical target volume (CTV) and OARs. The RPSS was calculated for each treatment plan comparing VMAT and IMPT.

RESULTS

In 40 analysed treatment plans, the average and low dose volumes to various OARs were significantly reduced when using IMPT compared to VMAT (p < 0.05). Using the RPSS, a significant difference between both treatment modalities was found, with 85% of the patients having a lower RPSS in favour of the IMPT plan.

CONCLUSION

There are dosimetric differences between IMPT and VMAT in pilocytic astrocytoma patients. In absence of clinically validated NTCP models we introduce the RPSS model in order to objectively compare treatment modalities by translating dosimetric differences in potential clinical differences.

Long-term health-related quality of life in pediatric brain tumor survivors receiving proton radiotherapy at <4 years of age

BACKGROUND

The purpose of this analysis is to report long-term health-related quality of life (HRQoL) among brain tumor survivors treated with proton therapy (PRT) at a very young age.

METHODS

Fifty-nine children <4 years old received PRT between 2000 and 2011. Forty families participated. HRQoL was assessed by child self-report (CSR; age ≥5) and parent proxy report (PPR; age 2+) using the PedsQL Core.

RESULTS

The median age was 2.5 years (range, 0.3-3.8) at PRT and 9.1 years (5.5-18) at last follow-up. The most common diagnoses were ependymoma (n = 22) and medulloblastoma (n = 7). Median follow-up is 6.7 years (3-15.4). Follow-up mean CSR and PPR scores were: total core (78.4 and 72.9), physical (82.9 and 75.2), psychosocial (76.0 and 71.6), emotional (74.4 and 70.7), social (81.2 and 75.1), and school (72.4 and 69.9). Parent-reported HRQoL fell within a previously defined range for healthy children in 37.5% of patients, and for children with severe health conditions in 45% of patients. PPR HRQoL was stable from baseline to last follow-up among all domains except for social functioning. History of gastrostomy tube was significantly associated with poorer CSR and PPR HRQoL on multivariable analysis. Ninety percent of children functioned in a regular classroom, 14 (36%) used a classroom aid, 9 (23%) used an outside tutor, and 18 (46%) had an individualized education plan.

CONCLUSION

Long-term HRQoL among brain tumor survivors treated with PRT at a very young age is variable, with over a third achieving HRQoL levels commensurate with healthy children.

KEY POINTS

1. One third of survivors reported long-term HRQoL scores comparable to those of healthy children.2. Treatment for hydrocephalus or a feeding tube was associated with significantly lower HRQoL.3. Total core HRQoL scores remained stable from baseline to last follow-up.

Bridging the treatment gap in infant medulloblastoma: molecularly informed outcomes of a globally feasible regimen

BACKGROUND

Infant medulloblastoma represents an enormous challenge in neuro-oncology, due to their simultaneous high-risk of recurrence and high risk of severe neurodevelopmental sequelae with craniospinal irradiation. Currently infant medulloblastoma are treated with intensified protocols, either comprising intraventricular methotrexate or autologous transplant, both of which carry significant morbidity and are not feasible in the majority of the world. We sought to evaluate the molecular predictors of outcome in a cohort of infants homogeneously treated with induction chemotherapy, focal radiation and maintenance chemotherapy.

METHODS

In a retrospective analysis, 29 young children treated with a craniospinal irradiation sparing strategy from Hospital Garrahan in Buenos Aires were profiled using Illumina HumanMethylationEPIC arrays, and correlated with survival.

RESULTS

Twenty-nine children (range, 0.3-4.6 y) were identified, comprising 17 sonic hedgehog (SHH), 10 Group 3/4, and 2 non-medulloblastomas. Progression-free survival (PFS) across the entire cohort was 0.704 (95% CI: 0.551-0.899). Analysis by t-distributed stochastic neighbor embedding revealed 3 predominant groups, SHHβ, SHHγ, and Group 3. Survival by subtype was highly prognostic with SHHγ having an excellent 5-year PFS of 100% (95% CI: 0.633-1) and SHHβ having a PFS of 0.56 (95% CI: 0.42-1). Group 3 had a PFS of 0.50 (95% CI: 0.25-1). Assessment of neurocognitive outcome was performed in 11 patients; the majority of survivors fell within the low average to mild intellectual disability, with a median IQ of 73.5.

CONCLUSIONS

We report a globally feasible and effective strategy avoiding craniospinal radiation in the treatment of infant medulloblastoma, including a robust molecular correlation along with neurocognitive outcomes.

Retrospective study of late radiation-induced damages after focal radiotherapy for childhood brain tumors

PURPOSE

To study a robust and reproducible procedure to investigate a relation between focal brain radiotherapy (RT) low doses, neurocognitive impairment and late White Matter and Gray Matter alterations, as shown by Diffusion Tensor Imaging (DTI), in children.

METHODS AND MATERIALS

Forty-five patients (23 males and 22 females, median age at RT 6.2 years, median age at evaluations 11.1 years) who had received focal RT for brain tumors were recruited for DTI exams and neurocognitive tests. Patients' brains were parceled in 116 regions of interest (ROIs) using an available segmented atlas. After the development of an ad hoc, home-made, multimodal and highly deformable registration framework, we collected mean RT doses and DTI metrics values for each ROI. The pattern of association between cognitive scores or domains and dose or DTI values was assessed in each ROI through both considering and excluding ROIs with mean doses higher than 75% of the prescription. Subsequently, a preliminary threshold value of dose discriminating patients with and without neurocognitive impairment was selected for the most relevant associations.

RESULTS

The workflow allowed us to identify 10 ROIs where RT dose and DTI metrics were significantly associated with cognitive tests results (p<0.05). In 5/10 ROIs, RT dose and cognitive tests were associated with p<0.01 and preliminary RT threshold dose values, implying a possible cognitive or neuropsychological damage, were calculated. The analysis of domains showed that the most involved one was the "school-related activities".

CONCLUSION

This analysis, despite being conducted on a retrospective cohort of children, shows that the identification of critical brain structures and respective radiation dose thresholds is achievable by combining, with appropriate methodological tools, the large amount of data arising from different sources. This supported the design of a prospective study to gain stronger evidence.

Regional Responses in Radiation-Induced Normal Tissue Damage

Normal tissue side effects remain a major concern in radiotherapy. The improved precision of radiation dose delivery of recent technological developments in radiotherapy has the potential to reduce the radiation dose to organ regions that contribute the most to the development of side effects. This review discusses the contribution of regional variation in radiation responses in several organs. In the brain, various regions were found to contribute to radiation-induced neurocognitive dysfunction. In the parotid gland, the region containing the major ducts was found to be critical in hyposalivation. The heart and lung were each found to exhibit regional responses while also mutually affecting each other's response to radiation. Sub-structures critical for the development of side effects were identified in the pancreas and bladder. The presence of these regional responses is based on a non-uniform distribution of target cells or sub-structures critical for organ function. These characteristics are common to most organs in the body and we therefore hypothesize that regional responses in radiation-induced normal tissue damage may be a shared occurrence. Further investigations will offer new opportunities to reduce normal tissue side effects of radiotherapy using modern and high-precision technologies.

Referral Patterns and Treatment Delays in Medulloblastoma: A Large Academic Proton Center Experience

Purpose

Patient travel time can cause treatment delays when providers and families decide to seek proton therapy. We examined whether travel distance or referral pattern (domestic versus international) affects time to radiation therapy and subsequent disease outcomes in patients with medulloblastoma at a large academic proton center.

Patients and Methods

Children with medulloblastoma treated at MD Anderson (MDA) with a protocol of proton beam therapy (PBT) between January 4, 2007, and June 25, 2014, were included in the analysis. The Wilcoxon rank-sum test was used to study the association between time to start of radiation and distance. Classification- and regression-tree analyses were used to explore binary thresholds for continuous covariates (ie, distance). Failure-free survival was defined as the time interval between end of radiation and failure or death.

Results

96 patients were included in the analysis: 17 were international (18%); 19 (20%) were from Houston, Texas; 21 were from other cities inside Texas (21%); and 39 (41%) were from other US states. The median time from surgery to start of radiation was not significantly different for international patients (median = 1.45 months) compared with US patients (median = 1.15 months; P = .13). However, time from surgery to start of radiation was significantly longer for patients residing > 1716 km (> 1066 miles) from MDA (median = 1.31 months) than for patients residing ≤ 1716 km (≤ 1066 miles) from MDA (median = 1.05 months; P = .01). This 1- to 2-week delay (median = 7.8 days) did not affect failure-free survival (hazard ratio = 1.34; P = .43).

Conclusion

We found that short delays in proton access can exist for patients traveling long distances to proton centers. However, in this study, treatment delays did not affect outcomes. This highlights the appropriateness of PBT in the face of travel coordination. Investment by proton centers in a rigorous intake process is justified to offer timely access to curative PBT.

Psychological Outcomes, Health-Related Quality of Life, and Neurocognitive Functioning in Survivors of Childhood Cancer and Their Parents

Childhood cancer disrupts the lives of patients and their families and affects acute and long-term psychological health. This article summarizes (1) psychological challenges, including depression, anxiety, worries, and posttraumatic stress, as well as positive outcomes such as benefit finding and posttraumatic growth in young survivors and parents; (2) health-related quality of life; (3) interventions to support survivors and parents with psychological difficulties; and (4) neurocognitive problems and interventions to help alleviate them. Although many survivors and parents fare well in the long term, many survivors may benefit from interventions. Interventions should be further evaluated and integrated into routine clinical care.

Neurocognitive impairment following proton therapy for paediatric brain tumour: a systematic review of post-therapy assessments

BACKGROUND

Proton therapy (PT), frequently utilised to treat paediatric brain tumour (PBT) patients, eliminates exit dose and minimises dose to healthy tissues that theoretically can mitigate treatment-related effects including cognitive deficits. As clinical outcome data are emerging, we aimed to systematically review current evidence of cognitive changes following PT of PBT.

MATERIALS AND METHODS

We searched PubMed and Scopus electronic databases to identify eligible reports on cognitive changes following PT of PBT according to PRISMA guidelines. Reports were extracted for information on demographics and cognitive outcomes. Then, they were systematically reviewed based on three themes: (1) comparison with photon therapy, (2) comparison with baseline cognitive measures, to population normative mean or radiotherapy-naïve PBT patients and (3) effects of dose distribution to cognition.

RESULTS

Thirteen reports (median size (range): 70 (12-144)) were included. Four reports compared the cognitive outcome between PBT patients treated with proton to photon therapy and nine compared with baseline/normative mean/radiotherapy naïve from which two reported the effects of dose distribution. Reports found significantly poorer cognitive outcome among patients treated with photon therapy compared with proton therapy especially in general cognition and working memory. Craniospinal irradiation (CSI) was consistently associated with poorer cognitive outcome while focal therapy was associated with minor cognitive change/difference. In limited reports available, higher doses to the hippocampus and temporal lobes were implicated to larger cognitive change.

CONCLUSION

Available evidence suggests that PT causes less cognitive deficits compared with photon therapy. Children who underwent focal therapy with proton were consistently shown to have low risk of cognitive deficit suggesting the need for future studies to separate them from CSI. Evidence on the effect of dose distribution to cognition in PT is yet to mature.

Improved neuropsychological outcomes following proton therapy relative to X-ray therapy for pediatric brain tumor patients

BACKGROUND

Survivors of pediatric brain tumors are at risk for impaired development in multiple neuropsychological domains. The purpose of this study was to compare neuropsychological outcomes of pediatric brain tumor patients who underwent X-ray radiotherapy (XRT) versus proton radiotherapy (PRT).

METHODS

Pediatric patients who underwent either XRT or PRT and received posttreatment age-appropriate neuropsychological evaluation-including measures of intelligence (IQ), attention, memory, visuographic skills, academic skills, and parent-reported adaptive functioning-were identified. Multivariate analyses were performed to assess differences in neuropsychological outcomes and included tests for interaction between treatment cohort and follow-up time.

RESULTS

Between 1998 and 2017, 125 patients with tumors located in the supratentorial (17.6%), midline (28.8%), or posterior fossa (53.6%) compartments received radiation and had posttreatment neuropsychological evaluation. Median age at treatment was 7.4 years. The PRT patient cohort had higher estimated SES and shorter median time from radiotherapy completion to last neuropsychological evaluation (6.7 vs 2.6 y, P < 0.001). On multivariable analysis, PRT was associated with higher full-scale IQ (β = 10.6, P = 0.048) and processing speed (β = 14.4, P = 0.007) relative to XRT, with trend toward higher verbal IQ (β = 9.9, P = 0.06) and general adaptive functioning (β = 11.4, P = 0.07). Planned sensitivity analyses truncating follow-up interval in the XRT cohort re-demonstrated higher verbal IQ (P = 0.01) and IQ (P = 0.04) following PRT, with trend toward improved processing speed (P = 0.09).

CONCLUSIONS

PRT is associated with favorable outcomes for intelligence and processing speed. Combined with other strategies for treatment de-intensification, PRT may further reduce neuropsychological morbidity of brain tumor treatment.

Margin-Free Fractionated Stereotactic Radiation Therapy for Pediatric Brain Tumors

PURPOSE

Conventional radiation therapy (RT) to pediatric brain tumors exposes a large volume of normal brain to unwarranted radiation causing late toxicity. We hypothesized that in well demarcated pediatric tumors lacking microscopic extensions, fractionated stereotactic RT (SRT), without target volume expansions, can reduce high dose normal tissue irradiation without affecting local control.

METHODS AND MATERIALS

Between 2008 and 2017, 52 pediatric patients with brain tumors were treated using the CyberKnife (CK) with SRT in 180 to 200 cGy per fraction. Thirty representative cases were retrospectively planned for intensity modulated RT (IMRT) with 4-mm PTV expansion. We calculated the volume of normal tissue within the high or intermediate dose region adjacent to the target. Plan quality and radiation dose-volume dosimetry parameters were compared between CK and IMRT plans. We also reported overall survival, progression-free survival (PFS), and local control.

RESULTS

Tumors included low-grade gliomas (n = 28), craniopharyngiomas (n = 16), and ependymomas (n = 8). The volumes of normal tissue receiving high (≥80% of prescription dose or ≥40 Gy) or intermediate (80% > dose ≥50% of the prescription dose or 40 Gy > dose ≥25 Gy) dose were significantly smaller with CK versus IMRT plans (P < .0001 for all comparisons). With a median follow-up of 3.7 years (range, 0.1-9.0), 3-year local control was 92% for all patients. Eight failures occurred: 1 craniopharyngioma (marginal), 2 ependymomas (both in-field), and 5 low-grade gliomas (2 in-field, 1 marginal, and 2 distant).

CONCLUSIONS

Fractionated SRT using CK without target volume expansion appears to reduce the volume of irradiated tissue without majorly compromising local control in pediatric demarcated brain tumors. These results are hypothesis generating and should be tested and validated in prospective studies.

Radiation doses to brain substructures associated with cognition in radiotherapy of pediatric brain tumors

Background: Several brain substructures associated with cognition (BSCs) are located close to typical pediatric brain tumors. Pediatric patients therefore have considerable risks of neurocognitive impairment after brain radiotherapy. In this study, we investigated the radiation doses received by BSCs for three common locations of pediatric brain tumor entities. Material and methods: For ten patients in each group [posterior fossa ependymoma (PFE), craniopharyngioma (CP), and hemispheric ependymoma (HE)], the cumulative fraction of BSCs volumes receiving various dose levels were analyzed. We subsequently explored the differences in dose pattern between the three groups and used available dose response models from the literature to estimate treatment-induced intelligence quotient (IQ) decline. Results: Doses to BSCs were found to differ considerably between the groups, depending on their position relative to the tumor. Large inter-patient variations were observed in the ipsilateral structures of the HE groups, and at low doses for all three groups. IQ decline estimates differed depending on the model applied, presenting larger variations in the HE group. Conclusion: While there were notable differences in the dose patterns between the groups, the extent of estimated IQ decline depended more on the model applied. This inter-model variability should be considered in dose-effect assessments on cognitive outcomes of pediatric patients.

The European Society of Paediatric Oncology Ependymoma-II program Core-Plus model: Development and initial implementation of a cognitive test protocol for an international brain tumour trial

It is increasingly accepted that survival alone is an inadequate measure of the success of childhood brain tumour treatments. Consequently, there is growing emphasis on capturing quality of survival. Ependymomas are the third most frequently occurring brain tumours in childhood and present significant clinical challenges. European Society of Paediatric Oncology Ependymoma II is a comprehensive international program aiming to evaluate outcomes under different treatment regimens and improve diagnostic accuracy. Importantly, there has been agreement to lower the age at which children with posterior fossa ependymoma undergo focal irradiation from three years to either eighteen months or one year of age. Hitherto radiotherapy in Europe had been reserved for children over three years due to concerns over adverse cognitive outcomes following irradiation of the developing brain. There is therefore a duty of care to include longitudinal cognitive follow-up and this has been agreed as an essential trial outcome. Discussions between representatives of 18 participating European countries over 10 years have yielded European consensus for an internationally accepted test battery for follow-up of childhood ependymoma survivors. The 'Core-Plus' model incorporates a two-tier approach to assessment by specifying core tests to establish a minimum dataset where resources are limited, whilst maintaining scope for comprehensive assessment where feasible. The challenges leading to the development of the Core-Plus model are presented alongside learning from the initial stages of the trial. We propose that this model could provide a solution for future international trials addressing both childhood brain tumours and other conditions associated with cognitive morbidity.

Whole-ventricular irradiation for intracranial germ cell tumors: Dosimetric comparison of pencil beam scanned protons, intensity-modulated radiotherapy and volumetric-modulated arc therapy

Background

Whole-ventricular radiotherapy (WV-RT) followed by a boost to the tumor bed (WV-RT/TB) is recommended for intracranial germ cell tumors (IGCT). As the critical brain areas are mainly in the target volume vicinity, it is unclear if protons indeed substantially spare neurofunctional organs at risk (NOAR). Therefore, a dosimetric comparison study of WV-RT/TB was conducted to assess whether proton or photon radiotherapy achieves better NOAR sparing.

Methods

Eleven children with GCT received 24 Gy(RBE) WV-RT and a boost up to 40 Gy(RBE) in 25 fractions of 1.6 Gy(RBE) with pencil beam scanning proton therapy (PBS-PT). Intensity-modulated radiotherapy (IMRT) and volumetric-modulated arc therapy (VMAT) plans were generated for these patients. NOAR were delineated and treatment plans were compared for target volume coverage (TVC), homogeneity index (HI), inhomogeneity coefficient (IC) and (N)OAR sparing.

Results

TVC was comparable for all three modalities. Compared to IMRT and VMAT, PBS-PT showed statistically significant optimized IC, as well as dose reduction, among others, in mean and integral dose to the: normal brain (-35.2%, -32.7%; -35.2%, -33.0%, respectively), cerebellum (-53.7%, -33.1%; -53.6%, -32.7%) and right temporal lobe (-14.5%, -31.9%; -14.7%, -29.9%). The Willis' circle was better protected with PBS-PT than IMRT (-7.1%; -7.8%). The left hippocampus sparing was higher with IMRT. Compared to VMAT, the dose to the hippocampi, amygdalae and temporal lobes was significantly decreased in the IMRT plans.

Conclusions

Dosimetric comparison of WV-RT/TB in IGCT suggests PBS-PT's advantage over photons in conformality and NOAR sparing, whereas IMRT's superiority over VMAT, thus potentially minimizing long-term sequelae.

Safety and Feasibility of Magnetic Resonance Imaging Simulation for Radiation Treatment Planning in Pediatric Patients: A Single Institution Experience

Purpose

This study aimed to report on the safety, feasibility, and workflow of using magnetic resonance imaging (MRI) simulation, while immobilized in the treatment position, for radiation therapy treatment planning in the pediatric population.

Methods and Materials

Between May and December 2017, 10 pediatric patients completed both MRI and computed tomography imaging simulation in treatment immobilization for radiation therapy planning for central nervous system disease. We report our initial institutional experience and workflow of the use of MRI simulation in immobilization for treatment planning in this population.

Results

Ten pediatric patients successfully underwent MRI and computed tomography imaging simulation for CNS disease. Two patients required anesthesia for sedation during the simulations. From our initial experience, MRI simulation was tolerated by all 10 pediatric patients without any safety or clinical issues, including those who required anesthesia.

Conclusions

Our initial experience supports the use of MRI simulation for radiation treatment planning in the pediatric population, with and without anesthetic sedation, as a safe and feasible image-guidance tool. This is particularly useful in the treatment of pediatric patients because MRI simulation enables superior, soft-tissue, anatomic imaging for a more robust delineation of organs at risk and target volumes without increasing radiation exposure.

Long-Term Supratentorial Radiologic Effects of Surgery and Local Radiation in Children with Infratentorial Ependymoma

BACKGROUND

Current standard of care for children with infratentorial ependymoma includes maximal safe resection and local radiation of 54-59 Gray. High-dose local radiation has been associated with declines in multiple cognitive domains. The anatomic and physiologic correlates of this cognitive decline remain undefined, and there have been no radiographic studies on the long-term effects of this treatment paradigm.

METHODS

A comprehensive database of pediatric brain tumor patients treated at Stanford Children's from 2004-2016 was queried. Seven patients with posterior fossa ependymoma who were treated with surgery and local radiation alone, who had no evidence of recurrent disease, and had imaging suitable for analysis were identified. Diffusion-weighted magnetic resonance imaging datasets were used to calculate apparent diffusion coefficient maps for each subject, while arterial spin labeling datasets were used to calculate maps of cerebral blood flow. Diffusion-weighted imaging and arterial spin labeling datasets of 52 age-matched healthy children were analyzed in the same fashion to enable group comparisons.

RESULTS

Several statistically significant differences were detected between the 2 groups. Cerebral blood flow was lower in the caudate and pallidum and higher in the nucleus accumbens in the ependymoma cohort compared with controls. Apparent diffusion coefficient was increased in the thalamus and trended toward decreased in the amygdala.

CONCLUSIONS

Surgery and local radiation for posterior fossa ependymoma are associated with supratentorial apparent diffusion coefficient and cerebral blood flow alterations, which may represent an anatomic and physiologic correlate to the previously published decline in neurocognitive outcomes in this population.

Dose-volume metrics and their relation to memory performance in pediatric brain tumor patients: A preliminary study

BACKGROUND

Advances in radiation treatment (RT), specifically volumetric planning with detailed dose and volumetric data for specific brain structures, have provided new opportunities to study neurobehavioral outcomes of RT in children treated for brain tumor. The present study examined the relationship between biophysical and physical dose metrics and neurocognitive ability, namely learning and memory, 2 years post-RT in pediatric brain tumor patients.

PROCEDURE

The sample consisted of 26 pediatric patients with brain tumor, 14 of whom completed neuropsychological evaluations on average 24 months post-RT. Prescribed dose and dose-volume metrics for specific brain regions were calculated including physical metrics (i.e., mean dose and maximum dose) and biophysical metrics (i.e., integral biological effective dose and generalized equivalent uniform dose). We examined the associations between dose-volume metrics (whole brain, right and left hippocampus), and performance on measures of learning and memory (Children's Memory Scale).

RESULTS

Biophysical dose metrics were highly correlated with the physical metric of mean dose but not with prescribed dose. Biophysical metrics and mean dose, but not prescribed dose, correlated with measures of learning and memory.

CONCLUSIONS

These preliminary findings call into question the value of prescribed dose for characterizing treatment intensity; they also suggest that biophysical dose has only a limited advantage compared to physical dose when calculated for specific regions of the brain. We discuss the implications of the findings for evaluating and understanding the relation between RT and neurocognitive functioning.

Cognitive and Adaptive Outcomes After Proton Radiation for Pediatric Patients With Brain Tumors

PURPOSE

Radiation therapy is integral in treatment of pediatric brain tumors, but it is associated with negative long-term sequelae. Proton beam radiation therapy (PRT), which enables better focusing of radiation on tumors, may entail fewer sequelae. This prospective study examined cognitive and adaptive functioning in children and young adults treated with PRT.

METHODS AND MATERIALS

A total of 155 patients were assessed using age-appropriate measures for cognitive and adaptive functioning at start of or during PRT (baseline) and at follow-up. Mean age at baseline was 8.9 years; mean follow-up interval was 3.6 years. Diagnoses included medulloblastoma, craniopharyngioma, ependymoma, glial tumors, germ cell tumors, and others. The sample was divided by age at baseline (<6 years [N = 57, or 37%] and ≥6 years [N = 98, or 63%]) and by PRT field (craniospinal irradiation [CSI; 39%] and focal irradiation [61%]).

RESULTS

Scores for mean intelligence quotient (IQ) and adaptive functioning skills were in the average range at baseline and follow-up. Overall, mean IQ scores declined from 105.4 to 102.5 (P = .005); however, only the younger CSI group showed significant decline. Patients receiving CSI, regardless of age, appeared particularly vulnerable in IQ, processing speed, and working memory. Adaptive skills were stable across the 4 age-by-treatment field groups.

CONCLUSIONS

At a mean of 3.6 years after PRT, IQ declined slightly for the group, largely because of significant IQ decline in younger patients treated with CSI. No significant change was seen in patients <6 years treated with focal PRT or in older patients. Adaptive skills remained stable across age and treatment type.

Neuropsychological consequences of childhood medulloblastoma and possible interventions: A review

BACKGROUND

Children who have been treated for a medulloblastoma often suffer long-term cognitive impairments that often negatively affect their academic performance and quality of life. In this article, we will review the neuropsychological consequences of childhood medulloblastoma and discuss the risk factors known to influence the presence and severity of these cognitive impairments and possible interventions to improve their quality of life.

METHODS

This narrative review was based on electronic searches of PubMed to identify all relevant studies.

RESULTS

Although many types of cognitive impairments often emerge during a child's subsequent development, the core cognitive domains that are most often affected in children treated for a medulloblastoma are processing speed, attention and working memory. The emergence and magnitude of these deficits varies greatly among patients. They are influenced by demographic (age at diagnosis, parental education), medical and treatment-related factors (perioperative complications, including posterior fossa syndrome, radiation therapy dose, etc.), and the quality of interventions such as school adaptations provided to the child or rehabilitation programs that focus on cognitive skills, behavior and psychosocial functioning.

CONCLUSION

These patients require specialized and coordinated multidisciplinary rehabilitation follow-up that provides timely and adapted assessments and culminates in personalized intervention goals being set with the patient and the family. Follow-up should be continued until referral to adult services.

EANO guidelines for the diagnosis and treatment of ependymal tumors

Ependymal tumors are rare CNS tumors and may occur at any age, but their proportion among primary brain tumors is highest in children and young adults. Thus, the level of evidence of diagnostic and therapeutic interventions is higher in the pediatric compared with the adult patient population.The diagnosis and disease staging is performed by craniospinal MRI. Tumor classification is achieved by histological and molecular diagnostic assessment of tissue specimens according to the World Health Organization (WHO) classification 2016. Surgery is the crucial initial treatment in both children and adults. In pediatric patients with intracranial ependymomas of WHO grades II or III, surgery is followed by local radiotherapy regardless of residual tumor volume. In adults, radiotherapy is employed in patients with anaplastic ependymoma WHO grade III, and in case of incomplete resection of WHO grade II ependymoma. Chemotherapy alone is reserved for young children <12 months and for adults with recurrent disease when further surgery and irradiation are no longer feasible. A gross total resection is the mainstay of treatment in spinal ependymomas, and radiotherapy is reserved for incompletely resected tumors. Nine subgroups of ependymal tumors across different anatomical compartments (supratentorial, posterior fossa, spinal) and patient ages have been identified with distinct genetic and epigenetic alterations, and with distinct outcomes. These findings may lead to more precise diagnostic and prognostic assessments, molecular subgroup-adapted therapies, and eventually new recommendations pending validation in prospective studies.

The posterior cerebellum, a new organ at risk?

Eekers et al. have recently proposed a neuro-oncology atlas, which was co-authored by most centers associated in the European Proton Therapy Network (EPTN; Figure 1). With the introduction of new treatment techniques, such as integrated magnetic resonance imaging and linear accelerators (MR-linac) or particle therapy, the prediction of clinical efficacy of these more costly treatment modalities becomes more relevant. One of the side-effects of brain irradiation, being cognitive decline, is one of the toxicities most difficult to measure and predict. In order to validly compare different treatment modalities, 1) a uniform nomenclature of the organs at risk (OARs), 2) uniform atlas-based delineation [e.g., Eekers et al.], 3) long-term follow-up data with standardized cognitive tests, 4) a large patient population, and 5) (thus derived) validated normal tissue complication probability (NTCP) models are mandatory. Apart from the Gondi model, in which the role of the dose to 40% of both hippocampi (HC) proves to be significantly related to cognition in 18 patients, no similar models are available. So there is a strong need for more NTCP models, on HC, brain tissue and possible other relevant brain structures. In this review we summarize the available evidence on the role of the posterior cerebellum as a possible new organ at risk for cognition, which is deemed relevant for irradiation of brain and head and neck tumors.

[Formula: see text]Working memory and attention in pediatric brain tumor patients treated with and without radiation therapy

Children are at risk for cognitive difficulties following the diagnosis and treatment of a brain tumor. Longitudinal studies have consistently demonstrated declines on measures of intellectual functioning, and recently it has been proposed that specific neurocognitive processes underlie these changes, including working memory, processing speed, and attention. However, a fine-grained examination of the affected neurocognitive processes is required to inform intervention efforts. Radiation therapy (RT) impacts white matter integrity, likely affecting those cognitive processes supported by distributed neural networks. This study examined working memory and attention in children during the early delayed stages of recovery following surgical resection and RT. The participants included 27 children diagnosed with pediatric brain tumor, treated with (n = 12) or without (n = 15) RT, who completed experimental and standardized measures of working memory and attention (n-back and digit span tasks). Children treated with radiation performed less well than those who did not receive radiation on the n-back measure, though performance at the 0-back level was considerably poorer than would be expected for both groups, perhaps suggesting difficulties with more basic processes such as vigilance. Along these lines, marginal differences were noted on digit span forward. The findings are discussed with respect to models of attention and working memory, and the interplay between the two.

Clinical and Radiologic Outcomes in Adults and Children Treated with Pencil-Beam Scanning Proton Therapy for Low-Grade Glioma

PURPOSE

We assessed clinical and radiologic outcomes in adults and children with low-grade glioma (LGG) of the brain treated with pencil-beam scanning (PBS) proton therapy (PT).

MATERIALS AND METHODS

Between 1997 and 2014, 28 patients were treated with PBS PT, 20 (71%) of whom were younger than 18 years. Median age at start of PT was 12.3 years (range, 2.2-53.0 years). Nine patients (32%) underwent at least a subtotal resection; 12 (43%) underwent biopsy; and 7 (25%) were diagnosed radiographically. Twelve patients (43%) had grade II and 9 (32%) had grade I gliomas. Eleven patients (39%) received chemotherapy before PT. A median dose of 54 Gy (relative biologic effectiveness) was administered. Radiologic response to PT was determined using the Response Evaluation Criteria in Solid Tumors (RECIST). Eight domains of quality of life (QoL) for 16 pediatric patients were assessed prospectively by patients' parents using the pediatric QoL proxy questionnaire. Progression-free survival and overall survival (OS) were estimated by the Kaplan-Meier method. Median follow-up was 42.1 months for living patients.

RESULTS

Ten patients (36%) developed local, clinical failure. Three patients (11%) died, all of tumor progression. Radiographic tumor response by RECIST was evaluable in 11 patients: 9 (82%) with stable disease, 1 (9%) with partial response, and 1 (9%) with complete response to PT. Three-year OS and progression-free survival were 83.4% and 56.0%, respectively. No ≥ grade III acute toxicities were observed. Grade III, late radiation necrosis developed in 1 patient (4%). No appreciable change in pediatric QoL proxy scores in children was noted in any of the 8 domains at any time point.

CONCLUSION

Treatment with PBS PT is effective for LGG, with minimal acute toxicity and, in children, no appreciable decline in QoL. More patients and longer follow-up are needed to determine the long-term efficacy and toxicity of PT for LGG.

Measurement of neurodevelopmental changes in children treated with radiation for brain tumors: what is a true 'baseline?'

OBJECTIVE

To review the various ways in which baseline neuropsychological functioning is measured in the extant literature on pediatric brain tumors, describe the pros and cons of each approach, and increase the awareness of researchers as to the implications of each.

METHOD

We reviewed the literature from 1993 to 2013, and classified studies by baseline approach and explicitness of selection of approach.

RESULTS

There are multiple approaches to operationalizing baseline levels of ability and to assess change from baseline. Each approach has strengths and weaknesses, and selection may depend on the question under investigation. Approaches to baseline estimation varied widely with a trend over time toward reliance on statistical modeling. Researchers were often insufficiently explicit about the reasons for adopting a particular approach. The common use of standardized scores requires caution as they obscure critical inferential limitations about change and magnitude of change. Some viable approaches were infrequently used, such as actuarial prediction formulas. Multiple simultaneous methods akin to theory testing and formal methods of construct validation could enhance scientific yield since all approaches are fallible.

CONCLUSIONS

Estimating baseline neuropsychological functioning is very challenging, particularly when it concerns children in the preschool years. Nevertheless, it is a crucial methodological decision with important implications for the interpretation of research findings that needs to be dealt with explicitly.

Neuroplastic Response After Radiation Therapy for Pediatric Brain Tumors: A Pilot Study

PURPOSE

Clinically effective measurement of cognitive toxicity from photon radiation therapy (XRT) should be accurate, sensitive, and specific. This pilot study tested translational findings on phasic changes in children's memory systems that are sensitive and insensitive to toxic XRT effects to identify a possible neuroplastic effect.

METHODS AND MATERIALS

Memory processes were prospectively tested before XRT and at 3 later time points up to 2 years in 35 children with mixed primary brain tumors who had not experienced recurrence. Memory processes were verbal-semantic, visual-semantic, and visual-perceptual, including accuracy, speed to recall, encoding, retrieval, and recognition. The mixed-effects model included time (to estimate slope), covariates (age, tumor locus, XRT field, and medications) as fixed effects, and individual random intercepts. A sensitivity analysis examined the influence of XRT dose to the hippocampi on memory.

RESULTS

Retrieval from long-term verbal-semantic memory declined 2 months after completing XRT, as seen in adults, and was lowest at 1 year, which was delayed in comparison with adults. Double dissociation from visual-perceptual memory at baseline and 2 months was found, consistent with adults. Recovery was demonstrated 2 years after XRT. Patterns were unchanged when dose to hippocampus was included in the model.

CONCLUSIONS

Verbal and semantic long-term retrieval is specifically sensitive to XRT-related cognitive dysfunction, without effect on visual-perceptual memory. Children reached nadir in XRT-sensitive memory 1 year after XRT and recovered by 2 years, which is later than that observed in adults. The protracted period of post-XRT injury may represent the maturation of the human hippocampus and white matter into late adolescence.

Long-Term Neurocognitive Functioning and Social Attainment in Adult Survivors of Pediatric CNS Tumors: Results From the St Jude Lifetime Cohort Study

PURPOSE

To assess the prevalence and severity of neurocognitive impairment in adult survivors of pediatric CNS tumors and to examine associated treatment exposures.

PATIENTS AND METHODS

Participants included 224 survivors of CNS tumors who were treated at St Jude Children's Research Hospital (current median age [range], 26 years [19 to 53 years]; time from diagnosis, 18 years [11 to 42 years]) and completed neurocognitive testing. Information on cranial radiation therapy (CRT) doses and parameters of delivery were abstracted from medical records. The prevalence of severe impairment (ie, at least two standard deviations below normative mean) was compared across radiation treatment groups (no CRT, focal irradiation, craniospinal irradiation) using the χ(2) test. Log-binomial models were used to estimate risk ratios (RRs) and corresponding 95% CIs for severe impairment.

RESULTS

In multivariable models, craniospinal irradiation was associated with a 1.5- to threefold increased risk of severe impairment compared with no CRT (eg, intelligence: RR = 2.70; 95% CI, 1.37 to 5.34; memory: RR = 2.93; 95% CI, 1.69 to 5.08; executive function: RR = 1.74; 95% CI, 1.24 to 2.45). Seizures were associated with impaired academic performance (RR = 1.48; 95% CI, 1.02 to 2.14), attention (RR = 1.54; 95% CI, 1.12 to 2.13), and memory (RR = 1.44; 95% CI, 1.04 to 1.99). Hydrocephalus with shunt placement was associated with impaired intelligence (RR = 1.78; 95% CI, 1.12 to 2.82) and memory (RR = 1.42; 95% CI, 1.03 to 1.95). Differential follow-up time contributed to variability in prevalence estimates between survivors treated with older nonconformal and those treated with more contemporary conformal radiation therapy methods. Neurocognitive impairment was significantly associated with lower educational attainment, unemployment, and nonindependent living.

CONCLUSION

Survivors of pediatric CNS tumors are at risk of severe neurocognitive impairment in adulthood. The prevalence of severe impairment is greater than expected in the general population, even in the absence of CRT, and is associated with disrupted attainment of adult social milestones.

Paediatric brain tumours: A review of radiotherapy, state of the art and challenges for the future regarding protontherapy and carbontherapy

BACKGROUND AND PURPOSE

Brain tumours are the most frequent solid tumours in children and the most frequent radiotherapy indications in paediatrics, with frequent late effects: cognitive, osseous, visual, auditory and hormonal. A better protection of healthy tissues by improved beam ballistics, with particle therapy, is expected to decrease significantly late effects without decreasing local control and survival. This article reviews the scientific literature to advocate indications of protontherapy and carbon ion therapy for childhood central nervous system cancer, and estimate the expected therapeutic benefits.

MATERIALS AND METHODS

A systematic review was performed on paediatric brain tumour treatments using Medline (from 1966 to March of 2014). To be included, clinical trials had to meet the following criteria: age of patients 18 years or younger, treated with radiation, and report of survival. Studies were also selected according to the evidence level. A secondary search of cited references found other studies about cognitive functions, quality of life, the comparison of photon and proton dosimetry showing potential dose escalation and/or sparing of organs at risk with protontherapy; and studies on dosimetric and technical issues related to protontherapy.

RESULTS

A total of 7051 primary references published were retrieved, among which 40 clinical studies and 60 papers about quality of life, dose distribution and dosimetry were analysed, as well as the ongoing clinical trials. These papers have been summarized and reported in a specific document made available to the participants of a final 1-day workshop. Tumours of the meningeal envelop and bony cranial structures were excluded from the analysis. Protontherapy allows outstanding ballistics to target the tumour area, while substantially decreasing radiation dose to the normal tissues. There are many indications of protontherapy for paediatric brain tumours in curative intent, either for localized treatment of ependymomas, germ-cell tumours, craniopharyngiomas, low-grade gliomas; or panventricular irradiation of pure non-secreting germinoma; or craniospinal irradiation of medulloblastomas and metastatic pure germinomas. Carbon ion therapy is just emerging and may be studied for highly aggressive and radioresistant tumours, as an initial treatment for diffuse brainstem gliomas, and for relapse of high-grade gliomas.

CONCLUSION

Both protontherapy and carbon ion therapy are promising for paediatric brain tumours. The benefit of decreasing late effects without altering survival has been described for most paediatric brain tumours with protontherapy and is currently assessed in ongoing clinical trials with up-to-date proton devices. Unfortunately, in 2015, only a minority of paediatric patients in France can receive protontherapy due to the lack of equipment.

Strategies to improve the quality of survival for childhood brain tumour survivors

BACKGROUND

Tumours of the central nervous system (CNS) are the most frequent solid tumours and the second most frequent type of cancer in children and adolescents. Overall survival has continuously improved in Germany, since an increasing number of patients have been treated according to standardised, multicentre, multimodal treatment recommendations, trials of the German Paediatric Brain Tumour Consortium (HIT-Network) or the International Society of Paediatric Oncology-Europe (SIOP-E) during the last decades. Today, two out of three patients survive. At least 8000 long-term childhood brain tumour survivors (CBTS) are currently living in Germany. They face lifelong disease- and treatment-related late effects (LE) and associated socioeconomic problems more than many other childhood cancer survivors (CCS).

METHOD

We review the LE and resulting special needs of this particular group of CCS.

RESULTS

Despite their increasing relevance for future treatment optimisation, neither the diversity of chronic and cumulative LE nor their pertinent risk factors and subsequent impact on quality of survival have yet been comprehensively addressed for CBTS treated according to HIT- or SIOP-E-protocols. Evidence-based information to empower survivors and stakeholders, as well as medical expertise to manage their individual health care, psychosocial and educational/vocational needs must still be generated and established.

CONCLUSION

The establishment of a long-term research- and care network in Germany shall contribute to a European platform, that aims at optimising CBTSs' transition into adulthood as resilient individuals with high quality of survival including optimal levels of activity, participation and acceptance by society.

Proton beam therapy for pediatric ependymoma

BACKGROUND

The aim of this study was to evaluate the efficacy of proton beam therapy for pediatric patients with ependymoma.

METHODS

Proton beam therapy was conducted for six patients (three boys and three girls; age, 2-6 years; median, 5 years) with ependymoma. The tumors were WHO grades 2 and 3 in two and four patients, respectively. All patients underwent surgery (subtotal and gross total resection in three patients each) and proton beam therapy at doses of 50.4-61.2 GyE (median, 56.7 GyE). The mean doses to normal brain tissue in proton beam therapy and photon radiotherapy were simulated using the same treatment planning computed tomography images.

RESULTS

All patients completed the planned irradiation. The follow-up period was 13-44 months (median, 24.5 months) from completion of proton beam therapy and all patients were alive at the end of this period. Local recurrence in the treatment field occurred in one patient at 4 months after proton beam therapy at 50.4 GyE. Alopecia and mild dermatitis occurred in all patients, but there was no severe toxicity. One patient had a once-off seizure after proton beam therapy and alopecia persisted in another patient for 31 months, but no patients had difficulty with daily life. The simulation showed that proton beam therapy reduces the dose to normal brain tissue by approximately half compared with photon radiotherapy.

CONCLUSIONS

Proton beam therapy for pediatric ependymoma is safe, does not have specific toxicities, and can reduce irradiation of normal brain tissue.

Comparison of dose distributions hippocampus in high grade gliomas irradiation with linac-based imrt and volumetric arc therapy: a dosimetric study

The aim of this study was to assess the feasibility of sparing contralateral hippocampus during partial brain radiotherapy in high grade gliomas. 20 previously treated patients were replanned to 60 Gy in 30 fractions with sparing intensity-modulated radiotherapy (IMRT) and volumetric modulated arctherapy (VMAT) using the following planning objectives: 100 % of PTV covered by 95% isodose without violating organs at risk (OAR) and hot spot dose constraints. For each, standard intensity-modulated radiotherapy (IMRT) plans were generated, as well as sparing IMRT and VMAT plans which spared contralateral (hemispheric cases) hippocampus. When the three plans were compared, there was equivalent PTV coverage, homogeneity, and conformality. Sparing IMRT significantly reduced maximum, mean, V20, V30 and V40 hippocampus doses compared with standart IMRT and VMAT (p < 0.05). VMAT significantly reduced maximum left lens and mean eye doses compared with standart IMRT and sparing IMRT (p < 0.05). Brainstem, chiasm, left and right optic nerves, right eyes and lens doses were similar. VMAT significantly reduced monitor units compared with standart IMRT and sparing IMRT (p < 0.05). It is possible to spare contralateral hippocampus during PBRT for high grade gliomas using IMRT. This approach may reduce late cognitive sequelae of cranial radiotherapy.

Recent Technical Advances and Indications for Radiation Therapy in Low-Grade Glioma

The use of radiotherapy in low-grade glioma has been a topic of controversy over the past 2 decades. Although earlier studies showed no overall survival benefit and no dose response, recent studies demonstrate a possible synergism between radiotherapy and chemotherapy. However, many questions remained unanswered regarding the proper management including the potential roles of biological imaging in treatment planning, the role of reirradiation after recurrence, the role of intensity-modulated radiation therapy and proton beam radiotherapy, and the proper choice of chemotherapy agents. Further clinical trials are necessary to help integrate these new therapies and technologies into clinical practice.

Gamma deficits as a neural signature of cognitive impairment in children treated for brain tumors

Cognitive impairment is consistently reported in children treated for brain tumors, particularly in the categories of processing speed, memory, and attention. Although tumor site, hydrocephalus, chemotherapy, and cranial radiation therapy (CRT) are all associated with poorer function, CRT predicts the greatest deficits. There is a particularly high correlation between CRT and slowed information-processing speed. Cortical gamma-band oscillations have been associated with processing behaviorally relevant information; however, their role in the maintenance of cognition in individuals with processing deficits is unclear. We examined gamma oscillations using magnetoencephalography (MEG) in children undergoing CRT to test whether gamma characteristics can be a signature of cognitive impairment in this population. We collected resting-state data as well as data from baseline and active periods during two visual-motor reaction time tasks of varying cognitive loads from 18 healthy children and 20 patients. We found that only high-gamma oscillations (60-100 Hz), and not low-gamma oscillations (30-59 Hz), showed significant group differences in absolute power levels. Overall, compared with healthy children, patients showed the following: (1) lower total high-gamma (60-100 Hz) power during the resting state, as well as during task-related baseline and performance measures; (2) no change in gamma reactivity to increases in cognitive load; and (3) slower processing speeds both inside and outside MEG. Our findings show that high-gamma oscillations are disrupted in children after treatment for a brain tumor. The temporal dynamic of the high-gamma response during information processing may index cognitive impairment in humans with neurological injury.