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Erin N. Kiehna and Thomas E. Merchant

Object

The treatment of craniopharyngioma is highly controversial. Continued advances in limited surgery and radiation therapy have maintained excellent local disease control while minimizing treatment-related sequelae. Further analyses of outcomes are necessary to characterize the long-term effects of radiation therapy.

Methods

An extensive literature review was performed for all studies including radiation therapy, with or without surgery, for pediatric craniopharyngioma.

Results

The authors identified 32 papers describing radiation therapy for treatment of pediatric craniopharyngioma, with disease control ranging from 44 to 100%. Modern studies report at least 90% disease control with 5-year follow-up. Fifteen studies reported outcomes, demonstrating that more than two-thirds of patients treated with surgery and radiation therapy have favorable outcomes, and this rate is more than 85% in the modern era.

Conclusions

Conservative surgery and radiation therapy results in long-term disease control in pediatric patients with craniopharyngioma that is comparable to results obtained with radical surgery alone. However, children with craniopharyngioma remain vulnerable to late treatment failures and side effects from radiation therapy, including endocrinopathies, vasculopathies, and secondary tumors, which may be detrimental to the quality of life. Long-term follow-up beyond 5–10 years is necessary to assess tumor control relative to functional outcomes.

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Paul Klimo Jr., Garrett T. Venable, Frederick A. Boop, and Thomas E. Merchant

OBJECT

In this paper the authors present their experience treating children with recurrent craniopharyngioma who were initially managed with surgery followed by conformal radiation therapy (CRT).

METHODS

A departmental oncology information system was queried to identify all children (< 18 years old) who received CRT for a craniopharyngioma between 1998 and 2010 (inclusive) and specifically those who experienced tumor progression. For each patient, the authors recorded the type of recurrence (solid, cystic, or both), the time interval to first progression and each subsequent progression, the associated treatment complications, and disease status at last follow-up evaluation.

RESULTS

Among the 97 patients that met criteria for entry into this study, 18 (18.6%) experienced tumor progression (9 cystic, 3 solid, 6 cystic and solid). The median time to first recurrence was 4.62 years (range 1.81–9.11 years). The subgroup included 6 female and 12 male patients with a median age of 7.54 years (range 3.61–13.83 years). Ten patients experienced first progression within 5 years of CRT. The 5- and 10-year treatment-free survival rates for the entire cohort were 89.0% (95% confidence interval [CI] 80.5%–93.9%) and 76.2% (95% CI 64%–85%), respectively. Seven patients had a single episode of progression and 11 had more than 1. The time interval between each subsequent progression was progressively shorter. The 18 patients underwent 38 procedures. The median follow-up duration for this group was 9.32 years (range 4.04–19.0 years). Three patients died, including 1 from perioperative complications.

CONCLUSIONS

Craniopharyngioma progression after prior irradiation is exceedingly difficult to treat and local control is challenging despite repeated surgical procedures. Given our results, gross-total resection may need to be the surgical goal at the time of first recurrence, if possible. Decompressing new cyst formation alone has a low rate of long-term success.

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Thomas E. Merchant, Toni Haida, Ming-Hsien Wang, Jonathan L. Finlay, and Steven A. Leibel

✓ The authors conducted a retrospective review of the clinical and treatment characteristics and outcomes in 28 pediatric patients with anaplastic ependymoma treated with radiation therapy since the advent of computerized tomography (CT) (1978–1994). Twelve patients received craniospinal irradiation followed by a boost to the primary site, two received whole-brain radiation therapy followed by a boost to the primary site, and the remaining 14 were treated with focal radiation therapy. The mean dose to the primary site was 5486 cGy. With a median follow-up period of 86 months for the 14 surviving patients (range 31–201 months), the median disease-free survival, measured from the date of diagnosis to the time of recurrence after radiation therapy, was 40 months. The median disease-free survival measured from the start of radiation therapy was 32 months. The median overall survival rate has not been reached and the actuarial estimates of overall survival rates at 5 and 10 years were 56% and 38%, respectively. According to univariate analysis, the disease-free survival rate was significantly improved (p < 0.01) in patients who underwent a gross-total resection at diagnosis. Overall survival rates were negatively influenced by treatment with craniospinal and whole-brain irradiation. As calculated by multivariate analysis, increasing dosage to the primary site (p < 0.05), infratentorial location (p < 0.01), and gross-total resections (p < 0.02) resulted in the longest disease-free survival times. All 19 patients in whom treatment failed after radiation therapy suffered a recurrence at the primary site. In addition, one of these patients experienced subarachnoid dissemination. Radiation treatment recommendations for patients with ependymoma have been based on the tumor's location, perceived risk for dissemination, and malignant propensity. The significance of anaplastic histological classification is controversial. Differences in the disease-free and overall survival rates have been demonstrated between ependymomas and anaplastic ependymomas treated in the pre—CT era. The results of this study show that there is no benefit from craniospinal irradiation in this group of patients.

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Thomas E. Merchant, Erin N. Kiehna, Larry E. Kun, Raymond K. Mulhern, Chenghong Li, Xiaoping Xiong, Frederick A. Boop, and Robert A. Sanford

Object

A Phase II trial of conformal radiation therapy (CRT) for craniopharyngioma was conducted to determine whether the irradiated volume could be safely reduced to decrease effects on cognitive function.

Methods

Between July 1997 and January 2003, 28 pediatric patients (median age 7.3 ± 4.12 years) received CRT in whom doses (54–55.8 Gy) were administered to the gross tumor volume (solid and cystic components) surrounded by a 1-cm clinical target volume margin. Patients were evaluated serially with neuropsychometric testing. Statistical analyses were performed to determine the effect of clinical factors and radiation dosimetry on intelligence quotient (IQ).

The median follow-up period was 36.6 months (range 24.4–80 months). The estimated 3-year progression-free survival rate was 90.3 ± 7.3%. Three patients experienced local disease progression. Cognitive outcome for patients was adversely affected by the following factors: age younger than 7.4 years (p = 0.001), an interval between symptoms and diagnosis of more than 73 days (p = 0.06), more extensive surgery (p = 0.014), multiple surgical procedures (p = 0.002), diabetes insipidus (p = 0.02), hydrocephalus at diagnosis (p = 0.009), a cerebrospinal fluid shunt (p = 0.005), shunt revisions (p = 0.01), Ommaya reservoir laterality (p = 0.005), and cyst aspirations (p = 0.02). The percentage of total brain, supratentorial brain, or left temporal lobe volumes receiving a dose in excess of 45 Gy had a significant impact on longitudinal IQ.

Conclusions

The use of CRT with a 1-cm margin for clinical target volume results in tumor control equivalent to that achieved using conventionally planned radiation therapy. Surgical morbidity and a volume-receiving dose more than 45 Gy are factors affecting longitudinal IQ after CRT in patients treated for craniopharyngioma.

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Thomas E. Merchant, Heather Lee, Junhong Zhu, Xiaoping Xiong, Gregory Wheeler, Sean Phipps, Frederick A. Boop, and Robert A. Sanford

Object. The goal of this study was to determine the influence of hydrocephalus on intelligence quotient (IQ) in children with infratentorial ependymoma before and after the administration of focal radiation.

Methods. Measurements of ventricular size, including Evans index (EI), cella media index (CMI), frontal horn diameter (FHD), and ventricular angle, were performed using magnetic resonance imaging at the time of diagnosis and again at 3, 6, 9, and 12 months after the initiation of radiation therapy. Of the 59 patients (median age at time of radiation treatment, 4.1 years), the clinical diagnosis established in 50 (85%) was hydrocephalus and 23 (39%) required placement of a cerebrospinal fluid (CSF) shunt. Extent of resection was gross or near total in 50 (85%). Before and after radiation treatment, IQ was measured using age-appropriate testing. The correlation between multiple ventricular measurements and IQ was investigated using standard regression techniques and a generalized linear model. Patients with a higher EI (p = 0.04), CMI (p = 0.001), and FHD (p = 0.0002) at the time of diagnosis were more likely to have lower IQ scores before radiation treatment. Patients with higher CMI (p = 0.04) and FHD (p = 0.01) at the time of diagnosis were more likely to exhibit an increase in IQ score after radiotherapy. The rate of change in IQ after radiation treatment was positively correlated with the CMI intercept (p = 0.015) and negatively correlated with the rate of FHD change (p = 0.006).

Conclusions. Changes in IQ score before and after radiation treatment are significantly influenced by the extent and treatment of hydrocephalus at the time of diagnosis. Hydrocephalus is an important factor to include when analyzing the effects of treatment. Patients who undergo a second surgery for ependymoma are more likely to require the placement of a CSF shunt (p = 0.0001).

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Kathleen J. Helton, Michael Edwards, R. Grant Steen, Thomas E. Merchant, Mark V. Sapp, Frederick A. Boop, and James Langston

Object

After the resection of brain tumors in pediatric patients, it can be difficult to differentiate recurrent tumor from treatment effects. Although late-delayed reactions are thought to be permanent, in this study the authors sought to characterize transient brain lesions (TBLs) in the late-delayed period that completely resolved without imaging or neurological sequelae.

Methods

In a retrospective review of an institutional neuroimaging brain tumor database, 11 patients were identified who met the imaging criteria (transient T2-weighted hyperintense enhancing lesions outside of the tumor bed, which occurred after radiation and/or chemotherapy) and had undergone three-dimensional dosimetry; their radiographic, clinical, and radiation-dosimetry results were analyzed. In the 11 patients who had been treated with multiple protocols 17 loci of abnormality, including 43 discrete, asymptomatic TBLs, were detected. The median TBL diameter was 1 cm or smaller, without mass effect or necrosis, and occurred 10 months after radiation therapy, 11 months after chemotherapy, resolved by 3 months, and occurred within the high-dose radiation treatment volume (median 55.8 Gy). The findings from extended follow up revealed the development of additional permanent complications of radiation therapy within the radiation port in five of the 11 patients.

Conclusions

A benign form of treatment-induced brain injury in children, TBLs should be treated using short-interval follow up. When these lesions are identified as a result of their characteristic imaging features, location, and temporal course, TBLs may be clearly distinguished from recurrent tumor or radiation necrosis and do not require biopsy. Further studies are needed to determine whether patients with TBLs are at an increased risk of developing more severe treatment-related brain injury.

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Chiaho Hua, Barry L. Shulkin, Daniel J. Indelicato, Yimei Li, Xingyu Li, Frederick A. Boop, and Thomas E. Merchant

OBJECT

The aim of the study was to document postoperative cerebral glucose distribution before proton therapy using F-18 fluorodeoxyglucose positron emission tomography (FDG PET) in children with craniopharyngioma.

METHODS

Between August 2011 and April 2014, 50 patients (20 males, 30 females) enrolled in a prospective trial for craniopharyngioma underwent FDG PET imaging before proton therapy. Proton therapy was delivered using doublescattered beams with a total prescribed dose of 54 cobalt gray equivalent. Tracer uptake in each of 63 anatomical regions was computed after warping PET images to a 3D reference template in Talairach coordinates. Regional uptake was deemed significantly low or high if it exceeded age-corresponding 95% prediction intervals of the normal population. The reference group included 132 children with non-CNS-related diseases and normal-appearing cerebral FDG PET scans.

RESULTS

Median patient age at diagnosis was 8.5 years (range 2–18 years). Forty-eight patients underwent 1–4 tumor-related surgeries before proton therapy, including placement of an Ommaya reservoir in 14 patients. Sixteen patients had symptomatic hydrocephalus that was treated with temporary (external ventricular drain, n = 16) or permanent CSF shunting (ventriculoperitoneal shunt, n = 1). The most commonly seen PET abnormalities in patients before proton therapy were significantly reduced uptake in subregions of the frontal lobe (often involving more than 1 gyrus), medial and ventral portions of the temporal lobe, cingulate gyrus, and caudate nucleus. A significantly high uptake was frequently observed on the contralateral side, including the superior, medial, and inferior temporal gyri and a large portion of the parietal lobe. Statistically significant predictor variables identified in the multivariate analysis for the extent of hypometabolism were sex (p = 0.005), hydrocephalus (p = 0.026), and the number of tumor-related surgeries (p = 0.017).

CONCLUSIONS

Postoperative FDG PET of patients with craniopharyngioma revealed metabolic abnormalities in specific regions of the brain. The ability to identify anatomical metabolic defects in individual patients facilitates the investigation of brain injury in children with craniopharyngioma.

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Kathleen J. Helton, Michael Edwards, R. Grant Steen, Thomas E. Merchant, Mark V. Sapp, Frederick A. Boop, and James Langston

Object. After the resection of brain tumors in pediatric patients, it can be difficult to differentiate recurrent tumor from treatment effects. Although late-delayed reactions are thought to be permanent, in this study the authors sought to characterize transient brain lesions (TBLs) in the late-delayed period that completely resolved without imaging or neurological sequelae.

Methods. In a retrospective review of an institutional neuroimaging brain tumor database, 11 patients were identified who met the imaging criteria (transient T2-weighted hyperintense enhancing lesions outside of the tumor bed, which occurred after radiation and/or chemotherapy) and had undergone three-dimensional dosimetry; their radiographic, clinical, and radiation-dosimetry results were analyzed. In the 11 patients who had been treated with multiple protocols 17 loci of abnormality, including 43 discrete, asymptomatic TBLs, were detected. The median TBL diameter was 1 cm or smaller, without mass effect or necrosis, and occurred 10 months after radiation therapy, 11 months after chemotherapy, resolved by 3 months, and occurred within the high-dose radiation treatment volume (median 55.8 Gy). The findings from extended follow up revealed the development of additional permanent complications of radiation therapy within the radiation port in five of the 11 patients.

Conclusions. A benign form of treatment-induced brain injury in children, TBLs should be treated using short-interval follow up. When these lesions are identified as a result of their characteristic imaging features, location, and temporal course, TBLs may be clearly distinguished from recurrent tumor or radiation necrosis and do not require biopsy. Further studies are needed to determine whether patients with TBLs are at an increased risk of developing more severe treatment-related brain injury.

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Kristian Aquilina, Thomas E. Merchant, Carlos Rodriguez-Galindo, David W. Ellison, Robert A. Sanford, and Frederick A. Boop

Malignant transformation of craniopharyngioma is a rare event; only 3 cases have been reported in children, all in the Japanese literature. The authors describe 2 additional pediatric cases. Treatment in both of these cases consisted of multiple resections and external beam radiation therapy (EBRT). Malignant transformation occurred 7 and 8 years after EBRT. The authors also review another 6 cases in adults. A possible causative association with radiation therapy is discussed. As radiation is currently an important option in the management of craniopharyngiomas, this association requires further study.