Title: Sweet syndrome masquerading as a disseminated and pulmonary fungal disease in a child with acute myeloid leukemia: case report and review of the literature

Pediatric histiocytic neoplasms are hematopoietic disorders frequently driven by the BRAF-V600E mutation. Here we identified two BRAF gene fusions (novel MTAP-BRAF and MS4A6A-BRAF) in two aggressive histiocytic neoplasms. In contrast to previously described BRAF fusions, MTAP-BRAF and MS4A6A-BRAF do not respond to the paradox breaker RAF inhibitor (RAFi) PLX8394 due to stable fusion dimerization mediated by the N-terminal fusion partners. This highlights a significant and clinically relevant shift from the current dogma that BRAF-fusions respond similarly to BRAF-inhibitors. As an alternative, we show suppression of fusion-driven oncogenic growth with the pan-RAFi LY3009120 and MEK inhibition.

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.

Social determinants of health (SDoH) may impact outcomes in sickle cell disease (SCD). We conducted a comprehensive literature review of five electronic databases to elucidate the relationship between SDoH and SCD and identify gaps in the literature. Our search yielded 59 articles which we organized into five SDoH areas: Neighborhood and Built Environment, Health and Healthcare, Social and Community Context, Education, and Economic Stability. We found that social determinants, such as access to healthcare, were inconsistently evaluated. Improved recognition and understanding of SDoH should enhance the development of programs that directly address its detrimental effects on patients with SCD.

Introduction: Advanced intraocular retinoblastoma can be cured by enucleation, but spread of retinoblastoma cells beyond natural limits of the eye may lead to metastatic disease which is related to a high mortality. Adjuvant therapy after enucleation has been shown to prevent metastasis in children with risk factors for extraocular retinoblastoma. However, histological criteria and adjuvant treatment regimens vary and there is no unifying consensus on the optimal choice of treatment. Method: Data on guidelines for adjuvant treatment in European retinoblastoma referral centres were collected in an online survey among all members of the European Retinoblastoma group (EURbG) network. Extended information were gathered via personal Email communication. Results: Data were collected from 26 centres in 17 countries. Guidelines for adjuvant treatment were in place at 92.3% of retinoblastoma centres. There was a consensus on indication for and intensity of adjuvant treatment among more than 80% of all centres. The majority of centres use no adjuvant treatment for isolated focal choroidal invasion or prelaminar optic nerve invasion. Patients with massive choroidal invasion or postlaminar optic nerve invasion receive adjuvant chemotherapy, while microscopic invasion of the resection margin of the optic nerve or extension through the sclera are treated with combined chemo- and radiotherapy. Conclusion: Indications and adjuvant treatment regimens in European retinoblastoma referral centres are similar but not uniform. Further biomarkers in addition to histopathological risk factors could improve treatment stratification. The high consensus in European centres is an excellent foundation for a common European study with prospective validation of new biomarkers.

Introduction/Objectives: We evaluated the length of time immunocompromised children (ICC) remain positive for SARS-CoV-2, identified factors associated with viral persistence and determined cycle threshold (CT) values of children with viral persistence as a surrogate of viral load. Methods: We conducted a retrospective cohort study of ICC at a pediatric hospital from March 2020-2021. Immunocompromised status was defined as primary, secondary or acquired due to medical comorbidities/immunosuppressive treatment. The primary outcome was time to first-of-two consecutive negative SARS-CoV-2 Polymerase chain reaction (PCR) tests at least 24 hours apart. Testing of sequential clinical specimens from the same subject was conducted using the Centers for Disease Control (CDC) 2019-nCoV Real-Time RT-PCR Diagnostic Panel assay. Descriptive statistics, Kaplan-Meier curve median event times and log-rank-sum tests were used to compare outcomes between groups. Results: Ninety-one children met inclusion criteria. Median age was 15.5 years (IQR 8-18 yrs), 64% were male, 58% were white, and 43% were Hispanic/Latinx. Most (67%) were tested in outpatient settings and 58% were asymptomatic. The median time to two negative tests was 42 days (IQR 25.0,55.0), with no differences in median time by illness presentation or level of immunosuppression. Seven children had >1 sample available for repeat testing, and 5/7 (71%) children had initial CT values of <30, (moderate to high viral load); 4 children had CT values of <30 3-4 weeks later, suggesting persistent moderate to high viral loads. Conclusions: Most ICC with SARS-CoV-2 infection had mild disease, with prolonged viral persistence >6 weeks and moderate to high viral load.

Introduction.Despite progress obtained with current treatments,the event-free survival of high-risk neuroblastoma(HR-NB)patients does not exceed 40-50% and the prognosis in refractory or relapsed patients is poor,still representing a challenge for pediatric oncologist.Therapeutic Iodine-131 meta-iodobenzylguanidine(Th-131I-MIBG) is a recognized safe and potentially effective treatment in NB.Materials.In this retrospective study,we report outcome of 28 MIBG-avid NB patients with advanced disease,because refractory or relapsed,underwent,from 1996 to 2014,to Th-131I-MIBG administered shortly before(median of 17 days) high-dose chemotherapy with Busulfan and Melphalan(HD-BuMel) and autologous stem cell transplantation(ASCT)at Gaslini Institute in Genoa,with the aim to analyze feasibility,safety and efficacy of this approach.Results.Engraftment occurred in all patients after a median of 14(11-29)and 30 days(13-80)from ASCT for neutrophil and platelet respectively.No treatment-related deaths were observed.The main high grade(3-4)toxicity observed was oral and gastrointestinal mucositis in 78.6% and 7.1% of patients respectively,while high grade hepatic toxicity was observed in 10.7%;two patients developed veno-occlusive-disease(7.1%),completely responsive to defibrotide.Hypothyroidism was the main late complication occurred in 9 patients(31.1%).After Th-131MIBG and HD-BuMel, 19 patients(67.8%) showed an improvement of disease status.Over a median follow-up of 15.9 years,the 3-year and 5-year overall survival(OS)probability were 53%(CI 0.33-0.69)and 41%(CI 0.22-0.59)and the 3-year and 5-year rates of cumulative risk of progression/relapse were 64%(CI 0.47-0.81)and 73%(CI 0.55-0.88),respectively.MYCN amplification emerged as the only risk factor significantly associated with OS(HR 3.58;p0.041).Conclusion.Th-131I-MIBG administered shortly before HD-BuMel turned out to be a safe and effective regimen,suggesting it should be included in a sequential approach in patients with advanced MIBG-avid NB.These patients could be benefit to be manage in centers with proven expertise in these treatments.

BACKGROUND Adolescent and young adult (AYA) hematopoietic cell transplantation (HCT) survivors are at increased risk of metabolic syndrome and lean body mass (LBM) deficits. Resistance training (RT) is a potential intervention to improve LBM, metabolic fitness and reduce risk of cardiovascular disease. PROCEDURE Eligible participants ages 13-39 years, 80-120 days post-HCT, transfusion independent, and prednisone dose <1 mg/kg/day were approached. Baseline assessments of body composition (DXA), anthropometrics and strength testing were completed and participants were taught a 12-week, home-based RT intervention with weekly remote coaching. Follow-up assessments were at day +200 (FU1) and +365 post-HCT (FU2). Feasibility targets were 1) 60% enrollment of approached patients, 2) 80% completion of weekly phone calls and 3) 80% completion of the RT intervention and FU1 assessments. Acceptability was measured by recommendation of the intervention to an AYA HCT survivor. RESULTS Twenty of 31 (65%) eligible AYAs enrolled. Two participants failed to complete baseline measurements (1=scheduling barriers, 1=passive refusal) and 4 participants who completed baseline assessments did not receive the intervention (2=medical reasons, 2=no longer interested). Of the 13 who received the intervention, 11 (85%) completed FU1 and completed 88.5% of coaching calls. LBM (kg) increased or remained unchanged in 9/9 participants with complete body composition data at FU1 (mean 1.1 kg; 95%CI: 0.4,1.9). All participants who completed FU1 reported they would recommend the intervention to an AYA HCT survivor. CONCLUSIONS A home-based RT intervention in AYA HCT survivors early post HCT is both feasible and acceptable and may maintain or increase LBM.

Background It is unclear how intensity-modulated radiation therapy (IMRT) impacts long-term risk of second malignant neoplasms (SMNs) in childhood cancer patients. Procedure Patients aged 10 years, many solid SMNs after IMRT in childhood cancer survivors develop in the high dose region. These data serve as a foundation for comparison with other modalities of radiation treatment (e.g., proton therapy).

To the Editor,We read the letter entitled “Acute lymphoblastic leukemia onset in a 3-year-old child with COVID-19 ” by Marcia et al . with great interest and we hereby suggest to start chemotherapy within the same timeline as for non-COVID-19 acute lymphoblastic leukemia (ALL) patients, following our experience managing a 3-year-old boy with concomitant diagnoses of precursor B-ALL and COVID-19. The patient was a previously healthy boy who presented to our hospital with a two-month history of intermittent fevers, night sweats, fatigue and cervical lymphadenopathies. His mother had been tested positive for COVID-19 three months earlier. He had been seen by his family physician by teleconference at the onset of his symptoms, at which point a COVID-19 infection was suspected but not confirmed. The persistence of symptoms and new onset of bone pain led his parents to reconsult at our hospital. At presentation, he had no respiratory symptoms. Physical examination was remarkable for fever, tachycardia and cervical lymphadenopathies. Bloodwork revealed pancytopenia and circulating peripheral blasts. Inflammatory markers were elevated (fibrinogen 7.08 g/L; C-reactive protein 255 mg/L; sedimentation rate 63 mm/h; ferritin 185 ug/L; D-dimers 0.51 ug/ml). Capillary gas, renal function, hepatic function, coagulation studies (INR/aPTT) and cardiac biomarkers (troponin and pro-BNP) were normal. Chest radiograph (CXR) was normal. COVID-19 testing by nasopharyngeal swab was positive. Bone marrow aspiration revealed 80% precursor B lymphoblasts of hyperdiploid subtype.Patient was admitted to a dedicated COVID-19 ward. Given the absence of SARS-CoV-2 infection’s severity criteria, no COVID-19-specific treatment was initiated. Chemotherapy was started promptly once the diagnostic work-up was completed, 6 days following the patient’s confirmed COVID-19 diagnosis. The patient was treated with a three-drug chemotherapy induction based on National Cancer Institute standard-risk criteria consisting of methylprednisolone, vincristine and asparaginase. Supportive treatment consisted of intravenous hydration and allopurinol for tumor lysis prevention, empirical antibiotics, blood transfusions and prophylactic low molecular weight heparin for COVID-19-associated thromboembolic complications. The patient’s clinical course was favorable; fevers, bone pains, peripheral blasts and inflammatory markers resolved quickly following the steroid prophase. Persistent and unexplained tachycardia led to extensive investigations given concerns for COVID-19-related thromboembolic complications. Troponins, pro-BNP, electrocardiogram, echocardiography, CXR and chest CT scan were unremarkable, and the tachycardia improved with packed red blood cell transfusion. The first negative COVID-19 test was obtained on day 4 of induction therapy but came back positive 48 hours later. The patient was discharged on day 13 of induction therapy. Three consecutive nasopharyngeal swabs were negative on days 21, 23 and 38 following COVID-19 diagnosis (Fig.1). End-induction bone marrow aspiration was consistent with morphologic remission and end-induction minimal residual disease by flow cytometry was positive at 0.025%.This case demonstrates the feasibility of treating children with newly diagnosed ALL who tested positive for COVID-19, without chemotherapy delay or modification, nor specific COVID-19 treatments, as done by Marcia et al . The province of Quebec constitutes the COVID-19 epicenter in Canada with half of all Canadian cases; the prevalence of COVID-19-positive cases was 3.3% among children under the age of 10, 5.3% between the age of 10-20 years and 49.2% for people aged 50 years and above.1 Importantly, no death has been reported among children in the province of Quebec, while 97.6% of COVID-related deaths were among individuals over the age of 60 years.1 Children appear to be less affected from COVID-19 infection and exhibit a milder disease course compared to adults, although the impact of COVID-19 infection among pediatric oncology patients remains unknown.2-4 Current published recommendations in the management of pediatric oncology patients during the COVID-19 pandemic emphasize on the importance of pursuing protocol-prescribed chemotherapy regimens based on the curable nature of most pediatric malignancies and the milder COVID-19 disease course observed in the pediatric population.4 However, case reports of severe COVID-19 disease in pediatric oncology patients start to emerge,5 and management of concomitant COVID-19 infection and newly diagnosed ALL can be challenging. First, our patient presented with a multisystem inflammatory syndrome which made it difficult to discern whether he was symptomatic from the COVID-19 infection versus the leukemia itself. Furthermore, we questioned whether the positive COVID-19 test by polymerase chain reaction (PCR) amplification in our patient truly reflects active infection since there was a nearly 3-month period between the first positive test in his family and when our patient was first tested positive. The positive PCR test could result from prolonged viral shedding in an immunocompromised patient affected by his leukemia onset. Alternatively, a positive test does not necessarily indicate the presence of viable virus as Wolfel and colleagues demonstrated that virus could not be grown from samples obtained from hospitalized patients beyond the eighth day of illness.6 Therefore, the general approach to await a negative result prior to begin chemotherapy might cause significant therapy delay and adversely impact outcomes in newly diagnosed ALL patients during the COVID-19 pandemic. Indeed, our patient took over 23 days to have 2 consecutive negative PCR tests 48 hours apart. Furthermore, the use of COVID-19-specific antiviral treatment in non-critically ill children is controversial given the lack of efficacy in this population.7Antiviral treatment may have significant drug interactions with chemotherapy and contribute to additive gastrointestinal and myelosuppressive toxicities. Nevertheless, the benefit of dexamethasone in COVID-19-positive patients requiring respiratory support in reducing early mortality8 and the exquisite sensitivity of lymphoblasts to corticosteroids could be an effective early strategy to safely initiate therapy in newly diagnosed ALL patients affected with COVID-19, particularly for those presenting with oncologic emergencies such as hyperleukocytosis or mediastinal mass. As the COVID-19 pandemic continues to evolve, pediatric oncologists will be confronted with the ongoing challenge to manage newly diagnosed cancer patients with concomitant COVID-19 infection. International COVID-19 registries in pediatric oncology are actively collecting clinical data to comprehensively assess the impact of COVID-19 within this patient population and to develop standardized management guidelines.9 As for now, an assessment of risks and benefits to initiate or delay cancer therapy will need to be carefully balanced on a case-by-case basis according to the patient’s clinical symptoms, type of malignancy, evidence-based treatment options, and emerging knowledge of COVID-19’s impact in our young cancer patients.CONFLICT OF INTEREST: The authors declare no conflict of interest.REFERENCES1. INSPQ. Données COVID-190 au Québec. 2020.2. Lu X, Zhang L, Du H, et al. SARS-CoV-2 Infection in Children. N Engl J Med. 2020;382(17):1663-1665.3. Cruz AT, Zeichner SL. COVID-19 in Children: Initial Characterization of the Pediatric Disease. Pediatrics. 2020;145(6).4. Bouffet E, Challinor J, Sullivan M, Biondi A, Rodriguez-Galindo C, Pritchard-Jones K. Early advice on managing children with cancer during the COVID-19 pandemic and a call for sharing experiences. Pediatr Blood Cancer. 2020;67(7):e28327.5. Stokes CL, Patel PA, Sabnis HS, Mitchell SG, Yildirim IB, Pauly MG. Severe COVID-19 disease in two pediatric oncology patients.Pediatr Blood Cancer. 2020;67(9):e28432.6. Wolfel R, Corman VM, Guggemos W, et al. Virological assessment of hospitalized patients with COVID-2019. Nature.2020;581(7809):465-469.7. Chiotos K, Hayes M, Kimberlin DW, et al. Multicenter initial guidance on use of antivirals for children with COVID-19/SARS-CoV-2. J Pediatric Infect Dis Soc. 2020.8. Group RC, Horby P, Lim WS, et al. Dexamethasone in Hospitalized Patients with Covid-19 - Preliminary Report. N Engl J Med. 2020.9. Sullivan M, Bouffet E, Rodriguez-Galindo C, et al. The COVID-19 pandemic: A rapid global response for children with cancer from SIOP, COG, SIOP-E, SIOP-PODC, IPSO, PROS, CCI, and St Jude Global.Pediatr Blood Cancer. 2020;67(7):e28409.Figure 1. Variation of C-reactive protein (CRP) throughout the hospitalization course (blue line). COVID-19 test results are identified in green when positive and red when negative. The day of ALL diagnosis, the day of chemotherapy start (black arrows), the duration of hospitalization (red box) and the duration of symptoms (green box) are indicated. Induction chemotherapy includes: Methylprednisone/prednisone (Day 1-32), Vincristine (Day 4, 11, 18, 25), PEG-Asparaginase (Day 7) and intrathecal cytarabine (Day 1 & 18).

Background: To describe how parents and families of children with cancer evaluate the benefits and risks of using social media (SM) and how they navigate disagreements between oncologists’ advice and information found on SM. Procedure: Parents of children who had been previously diagnosed with cancer, and who had used SM for a purpose related to that child’s health were recruited through SM sites and nonprofit organizations across the U.S. and were invited to complete questionnaires about their experiences using SM; a subset of participants also completed a follow-up in-depth interview. Open-ended responses and interviews were analyzed using thematic analysis. Results: 90 parents completed written questionnaires; 21 completed follow-up interviews. 70% described experiencing a situation in which information shared on SM conflicted with information provided by their child’s oncologist. Although 86% discussed it with the oncologist and 70% described the response as positive, 78% retained negative feelings about the experience. Openness to discussing SM, honesty, transparency and humility regarding the limits of medicine, and shared decision-making regarding information found on SM were connected with reported trust in the oncologist. Conclusions: Parents offered valuable insights regarding their experiences navigating SM, including 8 recommendations for how pediatricians might approach discussing parental SM use. Future studies will evaluate the utility of these recommendations for pediatric clinicians.

Background and aims: Oral mucositis (OM) is common and distressing toxicity in children on chemotherapy. There is limited number of safe and effective therapeutic options available for OM. Ketamine oral rinse has shown promising results in few studies in adults. This randomized, double-blind placebo-controlled trial aimed to test the efficacy of ketamine mouthwash in reducing chemotherapy-induced severe OM pain in children. Methods: Children aged 8-18 years with severe OM were randomized to a single dose of ketamine mouthwash (4 mg/ml solution; dose 1 mg/kg) or a placebo. A sample size of 44 patients was determined. Pain score (6-point faces scale) was noted at baseline and 15, 30, 45, 60, 120, 180, and 240 min. The outcome variables were a reduction in pain score, need for rescue medications, and adverse events. Results: The baseline characteristics were comparable in the two groups. The mean OM pain at 60 min decreased by 1.64 points (CI 1.13-2.14) in the ketamine group and 1.32 points (CI 0.76-1.87) in the placebo group (p=0.425), with a group difference of 0.32 points. Rescue pain medication (at 60 min) was required in 13.6% in the ketamine group and 18.2% in the placebo group (p=1.000). There were no significant adverse events observed. Conclusions: Among children on cancer chemotherapy with severe OM, ketamine mouthwash at a dose of 1 mg/kg did not significantly reduce OM pain. It did not decrease the need for rescue pain medications. Further research is warranted to test higher doses of ketamine for a clinically significant effect.

Because they can experience neutropenia due to bone marrow failure, patients with Shwachman-Diamond syndrome (SDS) carry increased risk for serious infections compared to the general population; however, it has been unknown whether this predisposes them to COVID-19 infection or more significant complications. We compiled results from a survey distributed to participants in the Shwachman-Diamond Syndrome Registry between May and June 2021. In this report we describe the characteristics and outcomes of patients with SDS who had COVID-19. Patients reported a short clinical course without significant complications or severe cytopenias. Additionally, COVID-19 vaccines were well tolerated with only minor side effects.

Xeroderma pigmentosum (XP) is a rare genodermatosis characterized by defective DNA repair, leading to hypersensitivity to ultraviolet (UV) sunlight and predisposes to various cutaneous and non-cutaneous malignancies. Platinum compounds are used against cutaneous cancers as concurrent chemoradiotherapy. But the XP gene polymorphism has a potential role in metabolism of these agents and their susceptibility. Here, we report a case of cutaneous squamous cell carcinoma in a patient with XP who had severe toxicity to chemotherapy. We also discuss other similar cases reported in literature of this entity, to highlight this potentially lethal pharmacogenomic association.

Appropriate high-dose chemotherapy (HDC) for high-risk neuroblastoma has not yet been established. In Japan, a unique HDC regimen (called double-conditioning regimen) comprising two cycles of total 800 mg/m2 of thiotepa and total 280 mg/m2 of melphalan is widely used. To re-evaluate the safety and the efficacy of this regimen for high-risk neuroblastoma, the medical records of 41 patients with high-risk neuroblastoma who underwent the double-conditioning regimen followed by autologous peripheral blood stem cell rescue between 2002 and 2012 were reviewed. MYCN-amplified high-risk neuroblastomas were observed in 23 patients. All patients underwent intensive multidrug induction chemotherapy, but none underwent anti-GD2 antibody immunotherapy. The primary tumor was resected at the adequate time point. The median follow-up duration for living patients was 9.2 years (range = 5.5–14.0 years). The 5-year event-free survival (EFS) and overall survival (OS) rates from treatment initiation were 41.5% ± 7.7% and 56.1% ± 7.8%, respectively. The 5-year EFS of MYCN-amplified high-risk neuroblastoma patients was 60.9% ± 10.2%, which was significantly superior compared to MYCN-non-amplified high-risk neuroblastoma patients (16.7% ± 8.8%; P < 0.001). MYCN amplification was the most favorable prognostic factor for EFS (hazard ratio = 0.29; 95% confidence interval = 0.12–0.66). Of the 41 patients, 3 died because of regimen-related toxicity (infection, n = 2; microangiopathy, n = 1). The double-conditioning regimen with thiotepa and melphalan is effective for high-risk neuroblastoma, especially in patients with MYCN amplification. However, the double-conditioning regimen is toxic and warrants special attention in clinical practice.

COVID-19 in a child with severe aplastic anemiaYunus Murat Akçabelen1, Ayça Koca Yozgat1, Aslı Nur Parlakay2, Nese Yarali11 Department of Pediatric Hematology, Ankara City Hospital Children’s Hospital, Turkiye2 Department of Pediatric Infectious Disease, Ankara City Hospital Children’s Hospital, TurkiyeArticle type: Letter to the editörRunning Title: COVID-19 in pediatric aplastic anemiaKey words: COVID-19, children, aplastic anemiaDisclosures: noneWord counts: 625

Background: As in LMICs, the prognosis of childhood ALL in Indonesia was lower than in HICs. Indonesian-ALL2013 protocol resulted in more toxicities and abandonments than expected. Therefore, it was modified into a pilot ALL2016 protocol. Changes to the ALL2013 protocol: no anthracyclines in SR, dexamethasone replaced prednisone in reinduction for HR and some drugs were rescheduled. Procedure: We compare the outcome of ALL2013 and ALL2016. Results: A total of 383 children with ALL were diagnosed, 21 were excluded. ALL2013 included 174 patients (106 SR and 68 HR) and ALL2016 188 (91 SR and 97 HR). The outcome of the ALL2016 was better than the ALL2013 (pOS 67.0% vs 60.3%; p=0.087 and pEFS 50.0% vs 37.9%; p=0.012) even when the number of HR patients was significantly higher in ALL2016 (51.6% vs 39.1%). The ALL2016 showed an early advantage for SR patients (pEFS 56.7% vs 47.2%; p=0.114 and pOS 74.4% vs 69.8%; p=0.298) due to the decrease of toxic deaths (10.4% vs 5.5%; p=0.211) however the number of late relapses were still high (19.5% vs 13.2%; p=0.282). In the HR group, both pEFS and pOS were significantly better in ALL2016 (pEFS 43.3% vs 23.5%; p=0.010 and pOS 59.8% vs 45.6%; p=0.036) due to less relapses (14.4% vs 29.4%; p=0.019). Both SR and HR showed a smaller number of abandonments in ALL2016. Conclusions: After small changes in protocol, initial toxicity and abandonments were reduced and the pOS and pEFS were improved. However, relapses still need to be lessened in the next protocol.

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.