Paulino, Arnold C

BACKGROUNDBoth intensity‐modulated radiotherapy (RT) and passively scattered proton therapy have a risk of secondary malignant neoplasm (SMN) in children. To determine the influence of RT modality on the incidence of SMN after craniospinal irradiation (CSI), the authors compared the incidence of SMN in children who had medulloblastoma treated with either photon CSI plus an intensity‐modulated RT boost (group I) or passively scattered proton CSI plus a boost (group II).METHODSFrom 1996 to 2014, 115 children with medulloblastoma (group I, n = 63; group II, n = 52) received CSI followed by a boost to the tumor bed. Most patients had standard‐risk disease (63.5%). The median follow‐up was 12.8 years for group I and 8.7 years for group II.RESULTSThe 5‐year and 10‐year overall survival (OS) rates were 88.8% and 85.1%, respectively, for standard‐risk patients and 63.1% and 57.3%, respectively, for high‐risk patients, with no OS difference by RT modality (P = .81). Six SMNs were identified (4 in group I, 2 in group II). The 5‐year and 10‐year SMN incidence rates were 1.0% and 6.9%, respectively (0.0% and 8.0%, respectively, in group I; 2.2% and 4.9%, respectively, in group II; P = .74). Two SMNs occurred in the clinical target volume in the brain, 2 occurred in the exit dose region from the photon spinal field, 1 occurred in the entrance path of a proton beam, and 1 occurred outside the radiation field. There were no reported cases of secondary leukemia.CONCLUSIONSThis analysis demonstrates no difference in OS or SMN incidence between patients in groups I and II 10 years after RT.LAY SUMMARY One hundred fifteen children with medulloblastoma received radiotherapy (RT) with either photon craniospinal irradiation (CSI) and an intensity‐modulated RT boost (group I; n = 63) or passively scattered proton CSI and a boost (group II;, n = 52). The majority of children had standard‐risk disease (63.5%). The 5‐year and 10‐year overall survival rates were 88.8% and 85.1% for standard‐risk patients, respectively, and 63.1% and 57.3% for high‐risk patients, respectively, with no difference in overall survival by RT group (P = .81). The 5‐year and 10‐year second malignant neoplasm incidence rates were 1.0% and 6.9%, respectively, with no difference in second malignant neoplasm incidence according to RT group (P = .74).

Abstract Background Proton radiotherapy (PRT) may be associated with less neurocognitive risk than photon RT (XRT) for pediatric brain tumor survivors. We compared neurocognitive and academic outcomes in long‐term survivors treated with XRT versus PRT. Methods Survivors underwent neurocognitive evaluation >1 year after craniospinal (CSI) or focal PRT or XRT. Groups were compared using separate one‐way analyses of covariance for the CSI and focal groups. Results PRT ( n = 58) and XRT ( n = 30) subgroups were similar on gender (66% male), age at RT (median = 6.5 years), age at follow‐up (median = 14.6 years), and government assistance status (32%). PRT and XRT focal groups differed on follow‐up interval, shunt history, and total RT dose (all p < .05), whereas PRT and XRT CSI groups differed on follow‐up interval, baseline neurocognitive performance score, boost volume, and CSI dose (all p < .05). The PRT focal group outperformed the XRT focal group on inhibition/switching ( p = .04). The PRT CSI group outperformed the XRT CSI group on inattention/impulsivity (both p < .05). Several clinical variables (i.e., RT dose, boost field, baseline performance) predicted neurocognitive outcomes (all p < .05). The PRT focal group performed comparably to population means on most neurocognitive measures, while both CSI groups performed below expectation on multiple measures. The XRT CSI group was most impaired. All groups fell below expectation on processing speed, fine motor, and academic fluency (most p < .01). Conclusions Findings suggest generally favorable neurocognitive and academic long‐term outcomes following focal PRT. Impairment was greatest following CSI regardless of modality. Dosimetry and baseline characteristics are important determinants of outcome alone or in combination with modality.

AbstractTo examine the educational background, clinical practice, and preferences regarding continuing medical education (CME) among radiation oncologists who attended the 2019 meeting of the Pediatric Radiation Oncology Society (PROS), a survey consisting of 20 questions was distributed asking for demographic and educational background, clinical practice, and preferences regarding pediatric radiation oncology CME. Of 188 participants, 130 (69.2%) returned the questionnaire. More than 80% reported access to CT simulation, three‐dimensional radiotherapy, and general anesthesia while <30% had access to intraoperative radiotherapy, proton, and heavy particle therapy. After residency, 12.1% did further training in pediatric radiation oncology. When asked about further training in pediatrics after residency, 88.8% answered that there should be a formal training program beyond residency in order to treat children. More than 75% acquired knowledge in pediatric radiation oncology through journals, books, live meetings, and tumor boards. The results of this survey may help Pediatric Radiation Oncology Society (PROS) in creating guidelines and recommendations for improvement in pediatric radiation oncology training and practice support as well as the development of CME activities most likely to benefit practitioners.

Abstract Background Cranial radiotherapy (RT) is associated with risk for cognitive and adaptive dysfunction. Proton RT (PRT) is a technique hypothesized to spare cognition by reducing exposure to nontarget brain tissue. However, little is known regarding functional outcomes in survivors of pediatric brain tumor (BT) treated with PRT. The present study examined the relationship between cognitive and adaptive outcomes in pediatric BT survivors post‐PRT. Methods Survivors treated with either focal (n = 33) or craniospinal irradiation (CSI; n = 37) PRT completed neurocognitive evaluations approximately 5 years post‐treatment. Results of intelligence testing and ratings of adaptive functioning are reported. Mediation models examined the relationship among radiation field, cognition, and adaptive functioning. Results The PRT CSI group demonstrated worse cognitive outcomes than the PRT Focal group across each cognitive index (Cohen's d = 0.56–0.70). Parent ratings of adaptive functioning were also worse in the PRT CSI group than the PRT Focal group (Global Adaptive Composite, d = 0.53; conceptual skills, d = 0.67). Cognitive performance fully mediated the relationship between radiation field and adaptive outcomes, while controlling for group differences in tumor histology and RT dose. Conclusions Focal PRT survivors demonstrated generally positive outcomes with weaknesses in processing speed and aspects of adaptive functioning. CSI exposure was associated with more consistently poor cognitive and adaptive outcomes. The increased risk for adaptive dysfunction in the PRT CSI group appeared due to the effects of CSI on cognition. Efforts to reduce the volume of tissue exposure to RT remain important.

AbstractPurpose/Objective(s)Bladder and prostate are unfavorable sites for rhabdomyosarcoma (B/P‐RMS), and represent a challenging location for radiotherapy.Materials/MethodsNineteen patients with B/P‐RMS were enrolled on a prospective registry protocol (2008‐2017) and treated with chemotherapy, proton beam therapy (PBT), and surgical resection (n = 8; 42%). Emphasis was given to treatment technique, disease‐related outcomes, and toxicity associated with PBT.ResultsThe majority of patients had bladder RMS (74%) of embryonal histology (95%), Group III (68%), and intermediate‐risk disease by Children's Oncology Group (COG) risk stratification (89%). Seven patients (37%) had primary tumors >5 cm in size. All patients were treated according to COG protocols. With a median follow‐up of 66.2 months, 5‐year overall survival (OS) and progression‐free survival (PFS) were 76%. Four patients (21%) experienced disease relapse, all presenting with local failure. The 5‐year local control (LC) rate was 76%. Tumor size predicted LC, with 5‐year LC for patients with >5 cm tumors being 43% versus 100% for those with ≤5 cm tumors (P = .006). Univariate analysis demonstrated an effect of tumor size on OS (tumor >5 cm, hazard ratio [HR] 17.7, P = .049) and PFS (HR 17.7, P = .049). Acute grade 2 toxicity was observed in two patients (11%, transient proctitis). Late grade 2+ toxicity was observed in three patients (16%; n = 1 grade 2 skeletal deformity; n = 3 transient grade 2 urinary incontinence; one patient experienced both).ConclusionsPBT for B/P‐RMS affords promising disease‐related outcomes with an acceptable toxicity profile. Higher local failure rates were observed for larger tumors, supporting dose‐escalation components of ongoing RMS clinical trials.

Abstract Purpose Proton therapy is currently used in the management of pediatric tumors to decrease late toxicities. However, one of the criticisms of proton therapy is the limited data regarding efficacy on disease control. The purpose of this study was to examine local and distant control rates after proton therapy for neuroblastoma. Methods and materials Eighteen patients with high‐risk ( n = 16) and locally recurrent neuroblastoma ( n = 2) were treated with curative intent and received proton therapy to the primary site and up to three post‐induction MIBG‐avid metastatic sites. Primary sites ( n = 18) were treated to 21–36 Gy (relative biological effectiveness [RBE]), and metastatic sites ( n = 16) were treated to 21–24 Gy (RBE). Local control and survival rates were calculated using the Kaplan–Meier method. Results With a median follow‐up of 60.2 months, two‐ and five‐year local control rates at the irradiated primary site were 94% and 87%, respectively. No failures at irradiated distant metastatic sites were observed. The five‐year progression‐free survival (PFS) was 64%, and the five‐year overall survival (OS) was 94%. The extent of surgical resection was not associated with local control, PFS, or OS. No radiation‐related nephropathy or hepatopathy was reported. Conclusions Excellent local control was achieved using proton therapy to the primary and post‐induction MIBG‐positive distant sites. The predominant site of failure is progression in post‐induction non‐MIBG‐avid distant sites. Although proton therapy provides high rates of local control with acceptable toxicity for neuroblastoma, further advances in systemic therapy are needed for the improved control of systemic disease.

Abstract Purpose To determine the impact of surgery and/or radiation therapy on distant metastatic sites (DMS) in children with stage IV rhabdomyosarcoma (RMS). Methods A retrospective chart review was conducted on all patients with stage IV RMS at Texas Children's Hospital from 1992 to 2012. Data analyzed included age, gender, primary site, histologic subtype, number and sites of metastases, treatment including local therapy to DMS, and Oberlin score. Results The 5‐year progression‐free survival (PFS) and overall survival (OS) rates were 20% and 25%. The 5‐year PFS in patients receiving local therapy to all DMS (n = 16) and to less than all DMS (n = 19) was 31.3% versus 0% ( P = 0.002), whereas the 5‐year OS was 37.3% versus 0% ( P < 0.001), respectively. The 5‐year PFS in patients with isolated lung metastasis versus other types of metastasis was 29% versus 7% ( P = n.s.), whereas the 5‐year OS was 43% versus 10% ( P = 0.01). The 5‐year pulmonary local control was improved by the use of whole lung irradiation (WLI; 56% vs. 10%, P = 0.03). Conclusions Local treatment to all metastatic sites was associated with improved PFS and OS at 5 years. The use of WLI improved pulmonary control in patients with lung metastasis. We recommend an aggressive approach including local therapy to DMS in children with stage IV RMS.