Outcomes following proton therapy for pediatric esthesioneuroblastoma.

BACKGROUND: Pediatric esthesioneuroblastoma (EN) can infiltrate skull base anatomy, presenting challenges due to high radiation doses and pediatric tissue sensitivity. This study reports outcomes of pediatric EN treated with proton radiotherapy (PT). PROCEDURE: Using an IRB-approved prospective outcomes registry, we evaluated patient, tumor, and treatment-related variables impacting disease control and toxicity in pediatric nonmetastatic EN treated with modern multimodality therapy, including PT. RESULTS: Fifteen consecutive patients (median age 16) comprising Kadish stage B (n = 2), C (n = 9), and D (n = 4) tumors were assessed, including six with intracranial involvement, four with cranial nerve deficits, and four with cervical lymphadenopathy. Before radiation, two had subtotal and 13 had gross total resections (endoscopic or craniofacial). Two underwent neck dissection. Eleven received chemotherapy before radiation (n = 5), concurrent with radiation (n = 4), or both (n = 2). Median total radiation dose (primary site) was 66 Gy/CGE for gross disease and 54 Gy/CGE (cobalt Gray equivalent) for microscopic disease. Median follow-up was 4.8 years. No patients were lost to follow-up. Five-year disease-free and overall survival rates were 86% (no local or regional recurrences). Two patients developed vertebral metastases and died. Two required a temporary feeding tube for oral mucositis/dysphagia. Late toxicities included symptomatic retinopathy, major reconstructive surgery, cataracts, chronic otitis media, chronic keratoconjunctivitis, hypothyroidism, and in-field basal cell skin cancer. CONCLUSIONS: A multimodality approach for pediatric EN results in excellent local control. Despite the moderate-dose PT, serious radiation toxicity was observed; further dose and target volume reductions may benefit select patients. Longer follow-up and comparative data from modern photon series are necessary to fully characterize any relative PT advantage.

Proton therapy and limited surgery for paediatric and adolescent patients with craniopharyngioma (RT2CR): a single-arm, phase 2 study.

BACKGROUND: Compared with photon therapy, proton therapy reduces exposure of normal brain tissue in patients with craniopharyngioma, which might reduce cognitive deficits associated with radiotherapy. Because there are known physical differences between the two methods of radiotherapy, we aimed to estimate progression-free survival and overall survival distributions for paediatric and adolescent patients with craniopharyngioma treated with limited surgery and proton therapy, while monitoring for excessive CNS toxicity. METHODS: In this single-arm, phase 2 study, patients with craniopharyngioma at St Jude Children's Research Hospital (Memphis TN, USA) and University of Florida Health Proton Therapy Institute (Jacksonville, FL, USA) were recruited. Patients were eligible if they were aged 0-21 years at the time of enrolment and had not been treated with previous radiotherapeutic or intracystic therapies. Eligible patients were treated using passively scattered proton beams, 54 Gy (relative biological effect), and a 0·5 cm clinical target volume margin. Surgical treatment was individualised before proton therapy and included no surgery, single procedures with catheter and Ommaya reservoir placement through a burr hole or craniotomy, endoscopic resection, trans-sphenoidal resection, craniotomy, or multiple procedure types. After completing treatment, patients were evaluated clinically and by neuroimaging for tumour progression and evidence of necrosis, vasculopathy, permanent neurological deficits, vision loss, and endocrinopathy. Neurocognitive tests were administered at baseline and once a year for 5 years. Outcomes were compared with a historical cohort treated with surgery and photon therapy. The coprimary endpoints were progression-free survival and overall survival. Progression was defined as an increase in tumour dimensions on successive imaging evaluations more than 2 years after treatment. Survival and safety were also assessed in all patients who received photon therapy and limited surgery. This study is registered with ClinicalTrials.gov, NCT01419067. FINDINGS: Between Aug 22, 2011, and Jan 19, 2016, 94 patients were enrolled and treated with surgery and proton therapy, of whom 49 (52%) were female, 45 (48%) were male, 62 (66%) were White, 16 (17%) were Black, two (2%) were Asian, and 14 (15%) were other races, and median age was 9·39 years (IQR 6·39-13·38) at the time of radiotherapy. As of data cutoff (Feb 2, 2022), median follow-up was 7·52 years (IQR 6·28-8·53) for patients who did not have progression and 7·62 years (IQR 6·48-8·54) for the full cohort of 94 patients. 3-year progression-free survival was 96·8% (95% CI 90·4-99·0; p=0·89), with progression occurring in three of 94 patients. No deaths occurred at 3 years, such that overall survival was 100%. At 5 years, necrosis had occurred in two (2%) of 94 patients, severe vasculopathy in four (4%), and permanent neurological conditions in three (3%); decline in vision from normal to abnormal occurred in four (7%) of 54 patients with normal vision at baseline. The most common grade 3-4 adverse events were headache (six [6%] of 94 patients), seizure (five [5%]), and vascular disorders (six [6%]). No deaths occurred as of data cutoff. INTERPRETATION: Proton therapy did not improve survival outcomes in paediatric and adolescent patients with craniopharyngioma compared with a historical cohort, and severe complication rates were similar. However, cognitive outcomes with proton therapy were improved over photon therapy. Children and adolescents treated for craniopharyngioma using limited surgery and post-operative proton therapy have a high rate of tumour control and low rate of severe complications. The outcomes achieved with this treatment represent a new benchmark to which other regimens can be compared. FUNDING: American Lebanese Syrian Associated Charities, American Cancer Society, the US National Cancer Institute, and Research to Prevent Blindness.

Simultaneous Diagnosis of Craniopharyngioma in 2 Brothers.

Craniopharyngioma is a rare suprasellar tumor. Approximately one-third of cases occur in pediatric patients. Depending on the size and extent of the lesion, the main treatment options include complete surgical removal of the tumor or limited surgery followed by radiotherapy. Craniopharyngiomas are not thought to be hereditary. Herein the authors present a case report of 2 brothers, ages 9 and 10, diagnosed with craniopharyngioma within weeks of each other and managed with different approaches. One sibling underwent gross total resection followed by observation while the other underwent biopsy followed by postoperative proton therapy.

Long-term outcomes of pediatric and young adult patients receiving radiotherapy for nonmalignant vascular anomalies.

BACKGROUND: Nonmalignant vascular anomalies (VA) comprise a heterogeneous spectrum of conditions characterized by aberrant growth or development of blood and/or lymphatic vessels and can cause significant morbidity. Little is known about outcomes after radiotherapy in pediatric and young adult patients with nonmalignant VA. METHODS: Thirty patients who were diagnosed with nonmalignant VA and treated with radiotherapy prior to 2017 and before the age of 30 were identified. Clinical and treatment characteristics and outcomes were recorded. RESULTS: Median age at first radiotherapy was 15 years (range 0.02-27). Median follow-up from completion of first radiotherapy was 9.8 years (range 0.02-67.4). Lymphatic malformations (33%), kaposiform hemangioendothelioma (17%), and venous malformations (17%) were the most common diagnoses. The most common indication for first radiotherapy was progression despite standard therapy and/or urgent palliation for symptoms (57%). After first radiotherapy, 14 patients (47%) had a complete response or partial response, defined as decrease in size of treated lesion or symptomatic improvement. After first radiotherapy, 27 (90%) required additional treatment for progression or recurrence. Long-term complications included telangiectasias, fibrosis, xerophthalmia, radiation pneumonitis, ovarian failure, and central hypothyroidism. No patient developed secondary malignancies. At last follow-up, three patients (10%) were without evidence of disease, 26 (87%) with disease, and one died of complications (3.3%). CONCLUSIONS: A small group of pediatric and young adult patients with nonmalignant, high-risk VA experienced clinical benefit from radiotherapy with expected toxicity; however, most experienced progression. Prospective studies are needed to characterize indications for radiotherapy in VA refractory to medical therapy, including targeted inhibitors.

Second tumor risk in children treated with proton therapy.

BACKGROUND: Out-of-field neutron dissemination during double-scattered proton therapy has raised concerns of increased second malignancies, disproportionally affecting pediatric patients due to the proportion of body exposed to scatter dose and inherent radiosensitivity of developing tissue. We sought to provide empiric data on the incidence of early second tumors. METHODS: Between 2006 and 2019, 1713 consecutive children underwent double-scattered proton therapy. Median age at treatment was 9.1 years; 371 were ≤3 years old. Thirty-seven patients (2.2%) had tumor predisposition syndromes. Median prescription dose was 54 Gy (range 15-75.6). Median follow-up was 3.3 years (range 0.1-12.8), including 6587 total person-years. Five hundred forty-nine patients had ≥5 years of follow-up. A second tumor was defined as any solid neoplasm throughout the body. RESULTS: Eleven patients developed second tumors; the 5- and 10-year cumulative incidences were 0.8% (95% CI, 0.4-1.9%) and 3.1% (95% CI, 1.5-6.2%), respectively. Using age- and gender-specific data from the Surveillance, Epidemiology, and End Results (SEER) program, the standardized incidence ratio was 13.5; the absolute excess risk was 1.5/1000 person-years. All but one patient who developed second tumors were irradiated at ≤5 years old (p < .0005). There was also a statistically significant correlation between patients with tumor predisposition syndromes and second tumors (p < .0001). Excluding patients with tumor predisposition syndromes, 5- and 10-year rates were 0.6% (95% CI, 0.2-1.7%) and 1.7% (95% CI, 0.7-4.0%), respectively, with all five malignant second tumors occurring in the high-dose region. CONCLUSION: Second tumors are rare within the decade following double-scattered proton therapy, particularly among children irradiated at >5 years old and those without tumor predisposition syndrome.

Outcomes following proton therapy for Ewing sarcoma of the cranium and skull base.

PURPOSE: Despite the dosimetric advantages of proton therapy, little data exist on patients who receive proton therapy for Ewing sarcoma of the cranium and skull base. This study reports local disease control and toxicity in such patients. MATERIALS/METHODS: We reviewed 25 patients (≤21 years old) with nonmetastatic Ewing sarcoma of the cranium and skull base treated between 2008 and 2018. Treatment toxicity was graded per the Common Terminology Criteria for Adverse Events v4.0. The Kaplan-Meier product limit method provided estimates of disease control and survival. RESULTS: Median patient age was 5.9 years (range, 1-21.7). Tumor subsites included the skull base (48%), non-skull-base calvarial bones (28%), paranasal sinuses (20%), and nasal cavity (4%). All patients underwent multiagent alkylator- and anthracycline-based chemotherapy; 16% underwent gross total resection (GTR) before radiation. Clinical target volume (CTV) 1 received 45 GyRBE and CTV2 received 50.4 GyRBE following GTR or 54-55.8 GyRBE following biopsy or subtotal resection. Median follow-up was 3.7 years (range, 0.26-8.3); no patients were lost. The 4-year local control, disease-free survival, and overall survival rates were 96%, 86%, and 92%, respectively. Two patients experienced in-field recurrences. One patient experienced bilateral conductive hearing loss requiring aids, two patients developed intracranial vasculopathy, and 6 patients required hormone replacement therapy for neuroendocrine deficits. None developed a secondary malignancy. CONCLUSION: Proton therapy is associated with a favorable therapeutic ratio in children with large Ewing tumors of the cranium and skull base. Despite its high conformality, we observed excellent local control and no marginal recurrences. Treatment dosimetry predicts limited long-term neurocognitive and neuroendocrine side effects.

Proton therapy following induction chemotherapy for pediatric and adolescent nasopharyngeal carcinoma.

PURPOSE: In children treated for nasopharyngeal carcinoma, proton therapy and postchemotherapy target volumes can reduce the radiation dose to developing tissue in the brain and the skull base region. We analyzed outcomes in children with nasopharyngeal carcinoma treated with induction chemotherapy followed by moderate-dose proton therapy. METHODS/MATERIALS: Seventeen patients with nonmetastatic nonkeratinizing undifferentiated/poorly differentiated nasopharyngeal carcinoma underwent double-scattered proton therapy between 2011 and 2017. Median age was 15.3 years (range, 7-21). The American Joint Committee on Cancer T and N stage distribution included the following: T1, one patient; T2, five patients; T3, two patients; and T4, nine patients; and N1, six patients; N2, nine patients; and N3, two patients. Median radiation dose to the primary target volume and enlarged lymph nodes was 61.2 Gy (range, 59.4-61.2). Uninvolved cervical nodes received 45 Gy (range, 45-46.8). All radiation was delivered at 1.8 Gy/fraction daily using sequential plans. In 11 patients, photon-based intensity-modulated radiotherapy was used for elective neck irradiation to optimize dose homogeneity and improve target conformity. All patients received induction chemotherapy; all but one received concurrent chemotherapy. Five received adjuvant beta-interferon therapy. RESULTS: Median follow-up was 3.0 years (range, 1.6-7.9). No patients were lost to follow-up. Overall survival, progression-free survival, and local control rates were 100%. Fifteen patients developed mucositis requiring enteral feeding (n = 14) or total parenteral nutrition (n = 1) during radiotherapy. Serious late side effects included cataract (n = 1), esophageal stenosis requiring dilation (n = 1), sensorineural hearing loss requiring aids (n = 1), and hormone deficiency (n = 5, including three with isolated hypothyroidism). CONCLUSION: Following induction chemotherapy, moderate-dose proton therapy can potentially reduce toxicity in the brain and skull base region without compromising disease control. However, further follow-up is needed to fully characterize and evaluate any reduction in long-term complications.

Early outcomes and patterns of failure following proton therapy for nonmetastatic intracranial nongerminomatous germ cell tumors.

BACKGROUND: Although dosimetric comparisons demonstrate the advantage of proton therapy (PT) over conventional radiotherapy for nongerminomatous germ cell tumors (NGGCT), clinical outcome data for this rare tumor are lacking. We sought to evaluate outcomes for children with NGGCT treated with PT. METHODS: Between 2007 and 2016, 14 children (median age 11, range, 5-19 years) with nonmetastatic NGGCT were treated with PT after induction chemotherapy. Most (8/14) were mixed germ cell. Five of 14 patients had complete resection of their primary tumor before radiation. Off study, eight patients received 36 Gy (RBE [relative biological effectiveness]) craniospinal irradiation (CSI). On study, two patients received 30.6 Gy (RBE) whole-ventricle irradiation and four received focal radiation alone. All patients received a total dose of 54 Gy (RBE) to the tumor/tumor bed. RESULTS: At a median follow-up of 2.8 years, all patients were alive with no local recurrences. Three-year progression-free survival was 86%. Both metastatic recurrences occurred in patients treated with focal radiation alone; one with an immature teratoma developed an isolated spinal recurrence 5 months after treatment. Another with a mixed germ cell tumor developed a multifocal ventricular and shunt tract recurrence 7 months after treatment. Serious toxicity was minimal, including cataracts and hormone deficiency, and limited to children who received CSI. CONCLUSION: Early outcomes in children treated for NGGCT suggest the high conformality of PT does not compromise disease control and yields low toxicity. This pattern of failure data adds to growing evidence suggesting chemotherapy followed by focal radiotherapy alone is inadequate in controlling localized NGGCT.

Outcomes following proton therapy for pediatric ependymoma.

BACKGROUND: Proton therapy can reduce the low and intermediate radiation dose to uninvolved brain tissue in children with intracranial ependymomas, which may improve functional outcomes and reduce second malignancies in survivors. Accordingly, ependymoma has become the most common pediatric tumor treated with proton therapy, yet data on efficacy and toxicity are limited. MATERIAL AND METHODS: Between June 2007 and February 2017, 179 children (≤21 years old) with nonmetastatic grade II/III intracranial ependymoma received proton therapy at our institution. Median age, 3.5 years (range, 0.7-21); 58% were male. Most (66%) tumors were in the posterior fossa and classified as WHO grade III (67%). 27% underwent multiple operations to maximize the extent of resection; ultimately 85% had a gross total or near total tumor resection before radiotherapy. 33% received preradiation chemotherapy. Median radiation dose in children ≤3 years old, 54 Gy(RBE). Most (>90%) children over 3 years old received 59.4 Gy(RBE). Patient and treatment variables were assessed for correlation with disease control. RESULTS: Median follow-up, 3.2 years. 3-year local control, progression-free survival, and overall survival rates were 85%, 76%, and 90%, respectively. First site of progression was local, metastatic, or simultaneous in 14, 17 and 6 patients, respectively. On multivariate analysis, subtotal resection was associated with inferior local control (67% vs. 88%; p ≤ .01) and progression-free survival (59% vs. 79%; p < .05). Male sex was associated with inferior progression-free (67% vs. 87%; p< .05) and overall survival (84% vs. 99%; p < .01). The 3-year CTCAE grade 2 + brainstem toxicity rate was 5.5% (95% CI: 2.9-10.2), including 1 grade 5 toxicity. CONCLUSIONS: This series of proton therapy for pediatric intracranial ependymoma demonstrates disease control comparable to photon series without unexpected toxicity. Subtotal resection and male sex were associated with inferior disease control. Additional follow-up to quantify the expected reductions in late toxicity with proton therapy is ongoing.

Clinical outcomes following proton therapy for children with central nervous system tumors referred overseas.

BACKGROUND: International, multidisciplinary care of children with central nervous system (CNS) tumors presents unique challenges. The aim of this study is to report patient outcomes of U.K. children referred for proton therapy to a North American facility. METHODS: From 2008 to 2016, 166 U.K. children with approved CNS tumors were treated with proton therapy at a single academic medical center in the United States. Median age was 7 years (range, 1-19). Median follow-up was 2.6 years. RESULTS: The 3-year actuarial overall survival (OS) and local control (LC) rates were 96% and 91%, respectively, for the overall group, 92% and 85% for the ependymoma subgroup (n = 57), 95% and 88% for the low-grade glioma subgroup (n = 54), and 100% and 100%, respectively, for the craniopharyngioma subgroup (n = 45). Cyst expansion was observed in 13 patients, including one case resulting in visual impairment. Serious side effects included new-onset seizures in three patients (1.8%), symptomatic vasculopathy in three patients (1.8%), and symptomatic brainstem necrosis in one patient (0.6%). CONCLUSIONS: In this cohort of British children referred overseas for proton therapy, disease control does not appear compromised, toxicity is acceptable, and improvement in long-term function is anticipated in survivors owing to the reduced brain exposure afforded by proton therapy.

Proactive enteral tube feeding in pediatric patients undergoing chemotherapy.

BACKGROUND: To determine feasibility and safety of proactive enteral tube feeding (ETF) in pediatric oncology patients. METHODS: Pediatric patients with newly diagnosed brain tumors, myeloid leukemia or high-risk solid tumors were eligible. Subjects agreeing to start ETF before cycle 2 chemotherapy were considered proactive participants (PPs). Those who declined could enroll as chart collection receiving nutritional standard of care. Nutritional status was assessed using standard anthropometric measurements. Episodes of infection and toxicity related to ETF were documented from diagnosis to end of therapy. A descriptive comparison between PPs and controls was conducted. RESULTS: One hundred four eligible patients were identified; 69 enrolled (20 PPs and 49 controls). At diagnosis, 17% of all subjects were underweight and 26% overweight. Barriers to enrollment included physician, subject and/or family refusal, and inability to initiate ETF prior to cycle 2 of chemotherapy. Toxicity of ETF was minimal, but higher percentage of subjects in the proactive group had episodes of infection than controls. Thirty-nine percent of controls eventually started ETF and were twice as likely to receive parenteral nutrition. PPs experienced less weight loss at ETF initiation than controls receiving ETF and were the only group to demonstrate improved nutritional status at end of study. CONCLUSIONS: Proactive ETF is feasible in children with cancer and results in improved nutritional status at end of therapy. Episodes of infection in this study are concerning; therefore, a larger randomized trial is required to further delineate infectious risks and toxicities that may be mitigated by improved nutritional status.

Outcomes of Infants and Young Children With Relapsed Medulloblastoma After Initial Craniospinal Irradiation-Sparing Approaches: An International Cohort Study.

PURPOSE: Infant and young childhood medulloblastoma (iMB) is usually treated without craniospinal irradiation (CSI) to avoid neurocognitive late effects. Unfortunately, many children relapse. The purpose of this study was to assess salvage strategies and prognostic features of patients with iMB who relapse after CSI-sparing therapy. METHODS: We assembled a large international cohort of 380 patients with relapsed iMB, age younger than 6 years, and initially treated without CSI. Univariable and multivariable Cox models of postrelapse survival (PRS) were conducted for those treated with curative intent using propensity score analyses to account for confounding factors. RESULTS: The 3-year PRS, for 294 patients treated with curative intent, was 52.4% (95% CI, 46.4 to 58.3) with a median time to relapse from diagnosis of 11 months. Molecular subgrouping was available for 150 patients treated with curative intent, and 3-year PRS for sonic hedgehog (SHH), group 4, and group 3 were 60%, 84%, and 18% (P = .0187), respectively. In multivariable analysis, localized relapse (P = .0073), SHH molecular subgroup (P = .0103), CSI use after relapse (P = .0161), and age ≥ 36 months at initial diagnosis (P = .0494) were associated with improved survival. Most patients (73%) received salvage CSI, and although salvage chemotherapy was not significant in multivariable analysis, its use might be beneficial for a subset of children receiving salvage CSI < 35 Gy (P = .007). CONCLUSION: A substantial proportion of patients with relapsed iMB are salvaged after initial CSI-sparing approaches. Patients with SHH subgroup, localized relapse, older age at initial diagnosis, and those receiving salvage CSI show improved PRS. Future prospective studies should investigate optimal CSI doses and the role of salvage chemotherapy in this population.

Randomized trial of hydroxychloroquine for newly diagnosed chronic graft-versus-host disease in children: a Children's Oncology Group study.

The Children's Oncology Group conducted a multicenter Phase III trial for chronic graft-versus-host disease (cGVHD). The double-blind, placebo-controlled, randomized study evaluated hydroxychloroquine added to standard therapy for children with newly diagnosed cGVHD. The study also used a novel grading and response scoring system and evaluated clinical laboratory correlates of cGVHD. The primary endpoint was complete response (CR) after 9 months of therapy. Fifty-four patients (27 on each arm) were enrolled before closure because of slow accrual. The CR rate was 28% in the hydroxychloroquine arm versus 33% in the placebo arm (odds ratio [OR] = 0.77, 95% confidence interval [CI]: 0.20-2.93, P = .75) for 42 evaluable patients. For 41 patients with severity assessment at enrollment, 20 (49%) were severe and 18 (44%) moderate according to the National Institutes of Health Consensus Conference global scoring system. The CR rate was 15% for severe cGVHD and 44% for moderate cGVHD (OR = 0.24, 95% CI: 0.05-1.06, P = .07). Although the study could not resolve the primary question, it provided important information for future cGVHD study design in this population.

Accuracy of central neuro-imaging review of DIPG compared with histopathology in the International DIPG Registry.

BACKGROUND: Diffuse intrinsic pontine glioma (DIPG) remains a clinico-radiologic diagnosis without routine tissue acquisition. Reliable imaging distinction between DIPG and other pontine tumors with potentially more favorable prognoses and treatment considerations is essential. METHODS: Cases submitted to the International DIPG registry (IDIPGR) with histopathologic and/or radiologic data were analyzed. Central imaging review was performed on diagnostic brain MRIs (if available) by two neuro-radiologists. Imaging features suggestive of alternative diagnoses included nonpontine origin, <50% pontine involvement, focally exophytic morphology, sharply defined margins, and/or marked diffusion restriction throughout. RESULTS: Among 286 patients with pathology from biopsy and/or autopsy, 23 (8%) had histologic diagnoses inconsistent with DIPG, most commonly nondiffuse low-grade gliomas and embryonal tumors. Among 569 patients with centrally-reviewed diagnostic MRIs, 40 (7%) were classified as non-DIPG, alternative diagnosis suspected. The combined analysis included 151 patients with both histopathology and centrally-reviewed MRI. Of 77 patients with imaging classified as characteristic of DIPG, 76 (99%) had histopathologic diagnoses consistent with DIPG (infiltrating grade II-IV gliomas). Of 57 patients classified as likely DIPG with some unusual imaging features, 55 (96%) had histopathologic diagnoses consistent with DIPG. Of 17 patients with imaging features suggestive of an alternative diagnosis, eight (47%) had histopathologic diagnoses inconsistent with DIPG (remaining patients were excluded due to nonpontine tumor origin). Association between central neuro-imaging review impression and histopathology was significant (p < 0.001), and central neuro-imaging impression was prognostic of overall survival. CONCLUSIONS: The accuracy and important role of central neuro-imaging review in confirming the diagnosis of DIPG is demonstrated.

Local Control After Proton Therapy for Pediatric Chordoma.

PURPOSE: Due to the location and high dose required for disease control, pediatric chordomas are theoretically well-suited for treatment with proton therapy, but their low incidence limits the clinical outcome data available in the literature. We sought to report the efficacy and toxicity of proton therapy among a single-institution cohort. METHODS AND MATERIALS: Between 2008 and 2019, 29 patients with a median age of 14.8 years (range, 3.8-21.8) received passive-scattered proton therapy for nonmetastatic chordoma. No patient received prior irradiation. Twenty-four tumors arose in the clivus/cervical spine region and 5 in the lumbosacral spine. Twenty-six tumors demonstrated classic well-differentiated histology and 3 were dedifferentiated or not otherwise specified. Approximately half of the tumors underwent specialized testing: 14 were brachyury-positive and 10 retained INI-1. Three patients had locally recurrent tumors after surgery alone (n = 2) or surgery + chemotherapy (n = 1), and 17 patients had gross disease at the time of radiation. The median radiation dose was 73.8 Gy relative biological effectivness (range, 69-75.6). RESULTS: With a median follow-up of 4.3 years (range, 1.0-10.7), the 5-year estimates of local control, progression-free survival, and overall survival rates were 85%, 82%, and 86%, respectively. No disease progression was observed beyond 3 years. Excluding 3 patients with dedifferentiated/not-otherwise-specified chordoma, the 5-year local control, progression-free survival, and overall survival rates were 92%, 92%, and 91%, respectively. Serious toxicities included 3 patients with hardware failure or related infection requiring revision surgery, 2 patients with hormone deficiency, and 2 patients with Eustachian tube dysfunction causing chronic otitis media. No patient experienced brain stem injury, myelopathy, vision loss, or hearing loss after radiation. CONCLUSIONS: In pediatric patients with chordoma, proton therapy is associated with a low risk of serious toxicity and high efficacy, particularly in well-differentiated tumors. Complete resection may be unnecessary for local control, and destabilizing operations requiring instrumentation may result in additional complications after therapy.

Irradiating Residual Disease to 30 Gy with Proton Therapy in Pediatric Mediastinal Hodgkin Lymphoma.

BACKGROUND: Local relapse is a predominant form of recurrence among pediatric patients with Hodgkin lymphoma (PHL). Although PHL radiotherapy doses have been approximately 20 Gy, adults with Hodgkin lymphoma receiving 30 to 36 Gy experience fewer in-field relapses. We investigated the dosimetric effect of such a dose escalation to the organs at risk (OARs). MATERIALS AND METHODS: Ten patients with PHL treated with proton therapy to 21 Gy involved-site radiation therapy (ISRT21Gy) were replanned to deliver 30 Gy by treating the ISRT to 30 Gy (ISRT30Gy), delivering 21 Gy to the ISRT plus a 9-Gy boost to postchemotherapy residual volume (rISRTboost), and delivering 30 Gy to the residual ISRT target only (rISRT30Gy). Radiation doses to the OARs were compared. RESULTS: The ISRT30Gy escalated the dose to the target by 42% but also to the OARs. The rISRTboost escalated the residual target dose by 42%, and the OAR dose by only 17% to 26%. The rISRT30Gy escalated the residual target dose by 42% but reduced the OAR dose by 25% to 46%. CONCLUSION: Boosting the postchemotherapy residual target dose to 30Gy can allow for dose escalation with a slight OAR dose increase. Treating the residual disease for the full 30Gy, however, would reduce the OAR dose significantly compared with ISRT21Gy. Studies should evaluate these strategies to improve outcomes and minimize the late effects.

Outcomes Following Proton Therapy for Pediatric Low-Grade Glioma.

PURPOSE: Dosimetric studies show that proton therapy can reduce the low/intermediate radiation dose to uninvolved tissue in children with low-grade glioma (LGG). For this reason, LGG is the fourth most common pediatric tumor treated with proton therapy, yet clinical outcome data on efficacy and toxicity are limited. METHODS AND MATERIALS: We reviewed the medical records of 174 children (≤21 years old) with nonmetastatic LGG enrolled on a prospective protocol and treated with proton therapy between 2007 and 2017. We assessed clinical outcomes and toxicity and analyzed patient, tumor, and treatment-related variables. RESULTS: The median age was 10.2 years (range, 2-21). Fifty-eight percent of tumors were World Health Organization grade 1 and 30% were grade 2; 12% were diagnosed on imaging characteristics alone. The most common histology was pilocytic astrocytoma (47%). The most common tumor subsites were diencephalon/optic pathway (52%), caudal brainstem (16%), and cerebellum (13%). Forty-two percent received chemotherapy before radiation therapy. The median follow-up was 4.4 years. The 5-year actuarial rates of local control, progression-free survival, and overall survival were 85% (95% confidence interval [CI], 78%-90%), 84% (95% CI, 77%-89%), and 92% (95% CI, 85%-95%), respectively. On univariate analysis, brainstem/spinal cord tumor location (62% vs 90% elsewhere) and dose <54 GyRBE (67% vs 91% for 54 GyRBE) were associated with inferior local control (P < .01 for both). Twenty-two patients (12.6%) experienced acute nausea or vomiting requiring ondansetron; 2 patients (1.1%) required corticosteroids. Serious toxicities (4% of patients) included brainstem necrosis requiring corticosteroids (n = 2), symptomatic vasculopathy (n = 2), radiation retinopathy (n = 1), epilepsy (n = 1), and death from radiation-induced high-grade glioma (n = 1). Thirty-nine patients (22%) developed new-onset central hormone deficiency. Pseudoprogression was observed in 32.1%. CONCLUSIONS: Compared with modern photon series, proton therapy reduces the radiation dose to developing brain tissue, diminishing acute toxicities without compromising disease control.

Autologous hematopoietic stem-cell transplantation for children with acute myeloid leukemia in first or second complete remission: a prognostic factor analysis.

PURPOSE: To determine prognostic factors correlated with outcomes after autologous hematopoietic stem-cell transplantation (HSCT) in children with acute myeloid leukemia (AML). PATIENTS AND METHODS: We studied 219 children who received autologous HSCT for AML in first complete remission (CR) and 73 children in second CR and who were reported to the Autologous Blood and Marrow Transplant Registry. Among 29 of 73 patients who underwent transplantation in second CR, duration of first CR was > or = 12 months. RESULTS: Three-year cumulative incidences of relapse were 37% (95% CI, 31% to 44%), 60% (95% CI, 41% to 74%), and 36% (95% CI, 20% to 53%) for children in first CR, second CR after a short (< 12 months) first CR, and second CR after a long (> or = 12 months) first CR, respectively. Corresponding 3-year probabilities of leukemia-free survival were 54% (95% CI, 47% to 60%), 23% (95% CI, 10% to 39%), and 60% (95% CI, 42% to 75%). In multivariate analyses, risks of relapse, mortality, and treatment failure (relapse or death, inverse of leukemia-free survival) were higher for patients in second CR after a short first CR than for the other two groups. Transplant-related mortality, treatment failure, and overall mortality rates were higher in older (> 10 years) children. CONCLUSION: Duration of first CR seems to be the most important determinant of outcome. Results in children who experience treatment failure with conventional chemotherapy support the use of autologous transplantation as salvage therapy if such patients achieve a subsequent CR.

Hematopoietic stem cell transplantation after first marrow relapse of non-T, non-B acute lymphoblastic leukemia: a pediatric oncology group pilot feasibility study.

BACKGROUND: Relapsed acute lymphoblastic leukemia (ALL) in children is associated with a poor outcome, especially for those patients whose relapse occurs during the first 36 months after diagnosis. The best therapy for these patients is not known. This study was designed to evaluate the feasibility of enrolling children with recurrent ALL in a standardized treatment protocol that included receipt of a hematopoietic stem cell transplant (HSCT). PROCEDURE: Eligible patients with a bone marrow relapse of non-T, non-B ALL underwent a common induction and consolidation followed by receipt of either an allogeneic HSCT from a human leukocyte antigen (HLA)-identical sibling or an autologous HSCT purged with B-4 blocked ricin. A common conditioning regimen was used for all patients. RESULTS: Twenty-eight patients from eight institutions were enrolled. Fourteen patients did not receive a transplant during the study, because of toxicity (4), relapse (1), inadequate purging (1), and parental or physician preference for an alternative donor transplant (8). Six patients received allogeneic HSCTs. Five of them have remained in remission for a median of 78 months. Eight patients received autologous HSCTs purged with B4-blocked ricin. Four have remained in remission for a median of 94 months. Of the nine patients who received alternative donor transplants, only two remain in remission. CONCLUSION: We conclude that well designed and controlled prospective studies are necessary to define the role of HSCTs in children with recurrent ALL. In order to be successful, such studies must have the full support of participating centers. Autologous HSC transplantation may have a role in the treatment of relapsed ALL, but further studies are needed.

A prospective double-blind randomized trial of urokinase flushes to prevent bacteremia resulting from luminal colonization of subcutaneous central venous catheters.

PURPOSE: This study was undertaken to determine if central venous catheter (CVC)-related infection in children with cancer could be prevented by monthly flushing of the catheter with urokinase. PATIENTS AND METHODS: Between August 1994 and July 1998, 103 patients with cancer were randomized at the time of subcutaneous CVC placement to receive monthly flushing of their catheters with either 5000 IU of urokinase-heparin or heparin alone. Patients subsequently had blood cultures taken from their CVCs during an episode of fever. RESULTS: Seventy-four of the 103 patients (72%) enrolled in the study received at least 6 catheter flushes: 40 with urokinase-heparin and 34 with heparin. The median number of flushes was 9.5 in the urokinase-heparin group and 10.2 in the heparin-only group (P = 0.62). There were 5 positive blood cultures in the urokinase-heparin group and seven in patients receiving heparin alone (P = 0.27). Staphylococcus epidermidis was isolated from the blood of 3 patients receiving urokinase-heparin and 6 in those receiving heparin alone (P = 0.17). CONCLUSION: Prophylactic monthly catheter flushes with 5000 IU urokinase did not significantly decrease the number of documented bacteremic events in children with cancer who have CVCs.