The AYA gap for rhabdomyosarcomaSimone Hettmer1 and Lars H. Lindner2Division of Pediatric Hematology and Oncology, Department of Pediatric and Adolescent Medicine, University Medical Center Freiburg, University of Freiburg, Freiburg, Germany.Department of Medicine III, LMU University Hospital, LMU Munich, Marchioninistr. 15, 81377, Munich, Germany.To whom correspondence should be addressed. Email: [email protected]. Phone: +49 761 270-45140; Fax: +49 761 270-4518Cancer is the leading cause of death among adolescents and young adults (AYAs). Cancers diagnosed during the AYA period - defined by the National Cancer Institute as the age from 15 to 39 years - account for approximately 5% of all cancers [1]. As per the national report on the status of cancer (study period 2015-2019, [1]), 5-year relative survival rates for both children and AYAs suffering from cancer are high (85.1% for children and 85.8% for AYAs), and improvements in survival over time appear to be similar for both age groups [1]. Yet, the spectrum of cancer types diagnosed in AYAs varies widely. The most common malignancies are female breast cancer (15%), thyroid cancer (15%), testicular cancer (8%) and melanomas (7%) [1], but AYAs may also suffer from so-called pediatric cancers with peak incidence during childhood. When compared to their childhood counterparts, worse outcomes were reported for AYAs diagnosed with pediatric cancers, including but not limited to leukemias [2] and sarcomas [3]. This „AYA gap“ is of concern to both pediatric and adult oncologists.The accompanying paper by Harrison et al examines a cohort of 2151 patients with rhabdomyosarcomas (RMS) enrolled in consecutive Children’s Oncology Group (COG) trials, including 19% AYAs aged 15-39 years and 81% children aged 0-14 years [4]. Compared to children with RMS, AYAs experienced significantly lower 5-year event-free survival (EFS; 44% vs. 67%) and 5-year overall survival (OS; 52% vs. 78%). These observations are in line with a recent retrospective analysis of nearly 2000 patients treated on European paediatric Soft Tissue Sarcoma Group (EpSSG) protocols [3]. Importantly, relative survival of AYAs with RMS treated on EpSSG and COG protocols appears to be better [3, 4] than the survival observed in epidemiological studies such as EUROCARE-5 (39,6% 5-year relative survival among RMS patients aged 15–19 years, and 36·4% for those aged 20–39 years; study period 2000-2007 [5]). Survival benefits for AYA patients treated on pediatric RMS protocols are consistent with previous observations in AYAs receiving treatment according to pediatric acute lymphoblastic leukemia (ALL) protocols [2] or at pediatric cancer centers/ sites with pediatric oncology expertise [6]. AYA cancer patients appear to benefit from chemotherapy dose intensities higher than what is generally prescribed to older patients. They may also draw advantages from pediatric standards with respect to planning of multimodal treatment and cancer staging. For example, the bone marrow (rarely ever involved in adult-type soft tissue sarcomas (STS)) is the most frequent site of metastases in AYAs with RMS treated within the COG cohort reported by Harrison et al [4] and should always be considered when planning pre-treatment examinations of AYAs with RMS. All taken together, adult oncology providers of AYA patients with RMS are well advised to consult their pediatric oncology colleagues and/ or consider referral to an institution with pediatric oncology expertise.AYA cancer patients treated on pediatric protocols – including those suffering from RMS - still experience worse outcomes than their pediatric counterparts [2]. There is ample evidence to support higher risk biology, more aggressive clinical phenotypes and higher rates of early treatment failures in AYAs diagnosed with pediatric cancers – including leukemias andsarcomas- compared to children diagnosed with the same malignancies [2-4]. For RMS tumors, higher rates of alveolar histology tumors and metastatic disease in AYAs were observed in the COG cohort reported here [4], as well as in the EpSSG and other retrospective studies [3, 7]. In addition to higher-risk disease manifestation, more frequent treatment-related toxicities and higher rates of withdrawal from treatment contribute to worse outcomes of AYAs compared to children with cancer [2]. There is a direct association between age and treatment-related deaths for patients undergoing ALL treatment on pediatric protocols [2]. Harrison et al do not comment on differences in treatment-related toxicities between children and AYAs with RMS, but higher rates of vincristine neurotoxicity, nausea and pain were previously reported in older adolescents undergoing RMS treatment on pediatric protocols. Even in the absence of higher-grade toxicities, a high burden of low-grade adverse events can have a major impact on the ability to function in daily life, continue education, maintain employment or participate in social activities. Many AYAs with cancer need to rely more on their parents/ support persons, which threatens their age-appropriate strive for autonomy and may result in them rebelling against treatment recommendations or failing to self- manage complex medication plans [8]. Active involvement of AYAs in the development of a care plan, which considers dignity, normalcy and family/ social relationships may improve compliance and, ultimately, treatment success.RMS is the most common STS in children and adolescents and often referred to as a pediatric cancer. Nevertheless, it occurs at any age, and up to 40% of all cases are diagnosed in adults (including seniors) [9]. The molecular and histological heterogeneity of pediatric RMS was studied intensively in recent years [10]. However, the insights provided by Harrison et al [4] and Ferrrai et al [3] emphasize that the remarkable diversity apparent across the RMS spectrum is multidimensional. Distinct clinical and biological characteristics of RMS diagnosed in different age groups deserve further attention. The two main pediatric RMS subtypes are embryonal and alveolar RMS, whereas pleomorphic RMS and RMS not otherwise specified are predominant in older adults and considered fundamentally different cancers [9]. To obtain a better understanding of RMS diagnosed in AYAs, future study efforts should aim at investigating the full spectrum of the disease and differentially consider the molecular underpinnings and therapeutic requirements of RMS diagnosed at opposite ends of the AYA age range.

INTRODUCTIONThe frequency of pediatric head and neck neoplasms ranges from approximately 2-15% of all pediatric cancers1. Skull base and calvarial neoplasms, including temporal bone and orbital masses are a subset of head and neck neoplasms occupying a number of neoplastic processes and categorically encompass several imaging patterns: singular dominant mass lesions with or without metastatic disease (e.g., rhabdomyosarcoma (RMS), chordoma), singular or multifocal metastatic disease (e.g., neuroblastoma), and multifocal disease due to systemic malignancy (e.g., leukemia, lymphoma, histiocytosis, etc.).While pathologies certainly vary between pediatric and adult patients, there remains significant overlap. As such, imaging protocols for skull base and calvarial neoplasms are similar in their general construct. However, optimized pediatric-specific protocols remain a must, as a retrofitted adult head and neck protocol is often ill equipped to offer quality, efficient and safe imaging (e.g., limiting radiation exposure) of the size-variable infant and pediatric patient. Moreover, sedation or general anesthesia is often required in the pediatric population in order to minimize motion artifact. Thus, optimization of imaging acquisition time is a very important technical consideration because it may decrease the necessity and duration of sedation/anesthesia and their potential risks in this vulnerable population. Standardized protocols for anatomic sub sites of the head and neck offer significant benefit in individual patient follow up on a local scale, and, on a broader scale, allow for collaborative understanding of imaging pathologies and innovative or benchmarked standardized treatment response assessment across institutions.In an effort to standardize protocols, this article offers minimum, pediatric specific anatomy-based initial and follow up imaging guidelines for pediatric malignancies of the orbits, calvarium, skull base and temporal bone. This manuscript was funded in part by the National Clinical Trials Network Operations Center Grant U10CA180886. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

Delayed but Successful T Cell Immune Reconstitution Following Umbilical Cord Blood Transplantation Conditioned with Thymoglobulin alone in IL-7Rα-mutated SCID Eman T. Al-Antary, MD1,5, Mary Caverly, CPNP2, Steve Buck3, Sharat Chandra, MD4, Süreyya Savaşan, MD1-3, 5

Prolonged Remission in Multiple Relapsed MLL-rearranged Infant B-ALL with Inotuzumab OzogamicinAkhila Lattupally MD1, Adonis Lorenzana MD1, Gregory Anthony Yanik MD2, Danielle Bell MD1,31. Ascension St. John Children’s Hospital, Detroit, Michigan, United States.2. C.S. Mott Children’s Hospital – University of Michigan, Ann Arbor, Michigan, United States.3. Children’s Hospital of Michigan, Detroit, Michigan, United States.Corresponding Author: Akhila Lattupally MDAddress: 22101 Moross Rd, PB2, Suite 70, Detroit, Michigan 48236Phone: 469-468-7978Fax: 313-343-4756Email:[email protected] Count: Main text: 841 wordsNumber of Tables: 0 Number of Figures: 0 Number of Supporting Information Files: 0Running Title: Remission in Infant ALL with Inotuzumab Ozogamicin.Keywords: Infant Leukemia, ALL Relapse, Immunotherapy

Pediatric immune thrombocytopenia (ITP) is an acquired disorder associated with autoimmune destruction and impairment of platelet production in children. Some children exhibit poor or transient response to ITP-directed treatments and are referred to as having refractory ITP (rITP). There is currently no consensus on the definition of rITP, nor evidence-based treatment guidelines for patients with rITP. After a survey of pediatric ITP experts demonstrated lack of consensus on pediatric rITP, we pursued a systematic review to examine the reported clinical phenotypes and treatment outcomes in pediatric rITP. The search identified 253 relevant manuscripts; following review, 11 studies proposed a definition for pediatric rITP with no consensus amongst them. Most definitions included sub-optimal response to medical management, while some outlined specific platelet thresholds to define this sub-optimal response. Common attributes identified in this study should be used to propose a comprehensive definition, which will facilitate outcome comparisons of future rITP studies.

Concurrence of a Kinase-dead BRAF and an OncogenicKRAS Gain-of-function Mutation in Juvenile Xanthogranuloma

Acute Myeloid Leukemia (AML) patients have a wide array of cytogenetic and molecular aberrations which can influence response to therapy. Monosomy7 (Mono7) is a rare subset within pediatric AML (prevalence of 4-5%), that is highly associated with poor outcomes. Fusions involving the ALK gene (14.3%) were exclusively identified within this high-risk cohort while absent across all other AML. Given the dismal outcomes of Mono7, we evaluated the use of crizotinib, an FDA-approved tyrosine kinase inhibitor, used to treat patients with ALK fusions. Our findings suggest that crizotinib may serve as a novel therapy for these patients.

Sickle cell disease is the most prevalent inherited blood disorder in the world, with significant morbidity and mortality. Patients often have recurrent painful vaso-occlusive episodes, and the American Society of Hematology gives a conditional recommendation for the use of regional anesthesia for acute sickle cell pain management. This scoping review summarizes the current evidence and identifies gaps for future research. Our screening process is outlined, and articles that mentioned the use of regional anesthesia for acute sickle cell crises were included. We present and interpret our results and highlight opportunities for future investigation.

Acute Lymphoblastic Leukemia of the Central Nervous System Presenting with Rapid Weight GainConnor P. Hall1 and Alan D. Friedman11Division of Pediatric Oncology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USACorrespondence: Alan D. Friedman, MDJohns Hopkins UniversityCRB I, Rm. 253 1650 Orleans St. Baltimore, Maryland 21231 Phone: 410-955-2095; Fax: 410-955-8897 Email: [email protected] Count: 863Number of Figures: 1Running Title: Rapid Weight Gain in ALLKey Words: acute lymphoblastic leukemia/ relapse/ weight gain/ central nervous systemAbbreviations:

We conducted a cross-sectional study using a questionnaire to explore the late effects in survivors of juvenile myelomonocytic leukemia (JMML). The attending pediatric hematologist oncologists completed the questionnaires. All survivors (N=30) had undergone allogeneic hematopoietic stem cell transplantation. Approximately 83% survivors showed more than one late effect. The identified late effects included endocrine, dental, skin, ophthalmologic, musculoskeletal, pulmonary, neurocognitive, and cardiovascular dysfunction. The prevalence of short stature and cardiovascular and kidney dysfunction was significantly elevated among survivors aged ≥18 years. Therefore, a multidisciplinary follow-up system for survivors of JMML is crucial.

The most common pediatric extragonadal pelvic cancers include germ cell tumors, sacrococcygeal teratomas, and rhabdomyosarcomas (arising from the urinary bladder, prostate, paratesticular tissues, vagina, uterus, and perineum). This manuscript describes the radiological and nuclear medicine features of these entities and provides consensus-based recommendations for the assessment at diagnosis, during and after treatment.

Purpose: Pediatric patients with medulloblastoma in LMICs are most treated with 3D conformal photon craniospinal irradiation (CSI), a time-consuming, complex treatment to plan, especially in resource-constrained settings. Therefore, we developed and tested a 3D conformal CSI autoplanning tool for varying patient lengths. Methods and Materials: Autocontours were generated with a deep learning model trained:tested (80:20 ratio) on 143 pediatric medulloblastoma CT scans (patient ages, 2-19 years, median=7 years). Using the verified autocontours, the autoplanning tool generated 2 lateral brain fields matched to a single spine field, an extended single spine field, or 2 matched spine fields. Additional spine sub-fields were added to optimize the corresponding dose distribution. Feathering was implemented (yielding 9-12 fields) to give a composite plan. Each planning approach was tested on 6 patients (ages, 3-10 years). A pediatric radiation oncologist assessed clinical acceptability of each autoplan. Results: The autocontoured structures’ average Dice similarity coefficient ranged from 0.65-0.98. The average V95 for the brain/spinal canal for single, extended, and multi-field spine configurations was 99.9±0.06%/99.9±0.10%, 99.9±0.07%/99.4±0.30%, and 99.9±0.06%/99.4±0.40%, respectively. The average maximum dose across all field configurations to the brainstem, eyes (L/R), lenses (L/R) and spinal cord were 23.7±0.08 Gy, 24.1±0.28 Gy, 13.3±5.27 Gy, 25.5±0.34 Gy, respectively (prescription=23.4 Gy/13 fractions). Of the 18 plans tested, all were scored as clinically acceptable as-is or clinically acceptable with minor, time-efficient edits preferred or required. No plans were scored as clinically unacceptable. Conclusion: The autoplanning tool successfully generated pediatric CSI plans for varying patient lengths in 3.50 ± 0.4 minutes on average, indicating potential for an efficient planning aid in resource-constrained settings.

Pediatric thyroid cancer is rare in children, however incidence is increasing. Papillary thyroid cancer and follicular thyroid cancer are the most common subtypes, comprising about 90% and 10% of cases respectively. This manuscript provides consensus imaging recommendations for evaluation of pediatric patients with thyroid cancer at diagnosis and during follow-up.

Title: BRAFMutation in Neuroblastoma: A Rare FindingAuthors: Sara C Hutchins1, Sara R Ferguson1, Geling Li2, Elizabeth A Beierle3*, Elizabeth Alva1

Sickle cell disease (SCD) requires coordinated, specialized medical care for optimal outcomes. There are no United States (US) guidelines that define a pediatric comprehensive SCD program. We report a modified Delphi consensus-seeking process to determine essential, optimal, and suggested elements of a comprehensive pediatric SCD center. Nineteen pediatric SCD specialists participated from the US. Consensus was predefined as 2/3 agreement on each element’s categorization. Twenty-six elements were considered essential (required for guideline-based SCD care), ten were optimal (recommended but not required), and five were suggested. This work lays the foundation for a formal recognition process of pediatric comprehensive SCD centers.

Background: Desmoid tumor (DT) is rare and challenging, often affects head neck (HN) region in children, and its appropriate treatments are under discussed. This study aimed to retrospectively evaluate long-term effectiveness and safety of 125I seed brachytherapy for pediatric DT in HN. Procedure: Seven pediatric patients with median age of 3 years old suffered from DT in HN treated with 125I brachytherapy from January 2008 to June 2018 were included. Among which, 5 underwent sole brachytherapy and the others combined with surgery under a prescription doses ranging from 10 000 cGy to 12 000 cGy. The rate of local control (LC), complete response (CR) and partial response (PR) were calculated after evaluation by radiological and pathological means. The radiation-associated toxicities were also evaluated Results: The LC rate was 7/7 during the follow-up time ranging from 43 to 135 months and with a mean of 57 months. No recurrent lesion was found in the patients receiving surgery combined with brachytherapy. In patients treated with sole brachytherapy, the radiological PR rate and CR rate were 4/5 and 1/5, respectively. In those reaching radiological PR, 3/4 were pathological CR. Slight acute radiation-associated toxicities were observed in all patients, and no late or severe acute toxicity was observed. Conclusion: 125I brachytherapy is effective and safe in the management of pediatric DT in HN as sole modality or combined with surgery in long term.

Rhabdomyosarcomas (RMS) are the most common pediatric soft tissue sarcomas. High-risk and metastatic disease continues to be associated with very poor prognosis. RMS model systems that faithfully recapitulate the human disease and provide rapid, cost-efficient estimates of anti-tumor efficacy of candidate drugs are needed to facilitate drug development and personalized medicine approaches. Here, we present a new zebrafish-based xenotransplant model allowing for rapid and easily accessible drug screening using low numbers of viable tumor cells and relatively small amounts of water-soluble chemicals. Under optimized temperature conditions, embryonal RMS-xenografts were established in zebrafish embryos at 3 hours post fertilization (hpf). In proof-of-principle experiments, chemotherapy drugs with established clinical anti-RMS efficacy (vincristine, dactinomycin) and the MEK inhibitor trametinib were shown to significantly reduce the cross-sectional area of the tumors by 120 hpf. RMS xenograft models in zebrafish embryos henceforth could serve as a valuable addition to cell culture and mammalian models of RMS and represent a rapid and cost-effective solution for pre-clinical candidate drug testing.

In this study, we reported a patient who presents with multicentric reticulohistiocytosis (MRH)-like clinical feature, but the histology is not compatible with it. Like our patient, a couple of patients described previously also had the dilemma that they could not be classified appropriately into any current histiocytosis entity. Considering the clinical and pathological features together, all these patients had a similar clinical profile: xanthomatous rash, erosive arthritis and histopathological findings showing xanthomized histiocytes. Therefore, we propose a new disease entity - xanthomatous erosive arthritis (XEA), to accommodate these patients that cannot be classified appropriately into the current system.