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BackgroundRelapsed/refractory high-risk neuroblastoma has a dismal prognosis. Anti-GD2-mediated chemo-immunotherapy has a notable anti-tumor activity in patients with relapsed/refractory high-risk neuroblastoma. The purpose of this study was to analyze the efficacy and safety of the combination of immunotherapy with dinutuximab beta (DB) and chemotherapy in patients with relapsed/refractory high-risk neuroblastoma.MethodsAll patients received the Turkish Pediatric Oncology Group NB 2009 national protocol for HR-NB treatment at the time of diagnosis. Salvage treatments were administered after progression or relapse. The patients who could not achieve remission in primary or metastatic sites were included in the study. The most common chemotherapy scheme was irinotecan and temozolomide. DB was administered intravenously for 10 days through continuous infusion with 10 mg/m2 per day. The patients received 2 to 14 successive cycles with duration of 28 days each. Disease assessment was performed after cycles 2, 4, and 6 and every 2 to 3 cycles thereafter.ResultsBetween January 2020 and March 2022, nineteen patients received a total of 125 cycles of DB and chemotherapy. Objective responses were achieved in 12/19 (63%) patients, including complete remission in 6/19 and partial response in 6/19. Stable disease was observed in two patients. The remaining five patients developed bone/bone marrow and soft tissue progression after 2-4 cycles of treatment. The most common Grade ≥3 toxicities were leukopenia, thrombocytopenia, hypertransaminasemia, fever, rash/itching and capillary leak syndrome, respectively.ConclusionOur study results suggest that DB-based chemo-immunotherapy seems to be suitable with encouraging response rates in patients with relapsed/refractory high-risk neuroblastoma.

Assestment of minimal residual disease (MRD) in childhood acute lymphoblastic leukemia (ALL) is of utmost importance both for risk classification and tailoring of the therapy. The data of pediatric ALL patients that received treatment with Berlin-Frankfurt-Münster (BFM) protocols were retrospectively collected from 5 university hospitals in Turkey. Of the 1388 patients enrolled in the study 390 were treated according to MRD-based protocols. MRD assestment was with real time quantitative polymerase chain reaction (qPCR) in 283 patients and with multiparametric flow cytometry (MFC)-MRD in 107 patients. MRD monitoring had upstaged a total of 8 patients (2%) from intermediate risk group to high-risk group. Univariate analysis revealed age 10 years or above, prednisone poor response, PCR-MRD ≥10−3 on day 33 and on day 78 as poor prognostic factors affecting event-free survival (EFS). Detection of >10% blasts on day 15 with MFC (MFC-high-risk group) was not shown to affect EFS and/or overall survival (log-rank P=0.339). Multiple logistic regression analysis revealed PCR-MRD ≥10−3 on day 78 as the only poor prognostic factor affecting EFS (odds ratio: 8.03; 95% confidence interval: 2.5-25; P=0.000). It is very important to establish the infrastructure and ensure necessary standardization for both MRD methods for optimal management of children with ALL.

To the Editor, Pyoderma gangrenosum (PG) is a rare ulcerative and neutrophilic dermatosis with unclear pathogenesis, which can be seen at any age. [1][2][3][4] PG is generally associated with systemic diseases. 5 Herein, we present a patient who developed PG during treatment for acute lymphoblastic leukemia (ALL). A 10-year-old female child who was diagnosed with T-cell ALL and treated with ALL-BFM 95 protocol developed painful nodular, abscesslike lesions at the end of the induction therapy. Lesions were detected on the anterior surface of the right tibia and in the left submandibular area. Culture samples were taken and antimicrobial treatment was initiated. In the follow-up, new lesions developed in various parts of the body. There was no growth in any of the cultures and the patient did not respond to treatment. The patient admitted to our center upon the request of her family. Physical examination revealed palpable fluctuating, abscess-like lesions in the interscapular area, under the mandible to the left of the midline, lateral to the right lumbar region in the abdomen, and on the skin in the left femur region (Figure 1A,B). Thorax computed tomography (CT) imaging showed circular-shaped consolidations in both lungs. Magnetic resonance imaging (MRI) revealed cystic lesions in the right paravertebral muscle tissue and the right paravertebral subcutaneous fatty tissue (Figure 1C,D,E). Work-up for immune deficiency including genetic analysis revealed normal results.

Background. Catheter-related bloodstream infection (CRBSI) is one of the most common complications of central lines. Data concerning the effectiveness and safety of antibiotic lock therapy (ALT), especially in pediatric hematology and oncology patients, have not yet reached sufficient levels of evidence. We aimed to share our center`s experience on ALT in pediatric cancer and to investigate the causes of ALT failure. Methods. All cases with CRBSI and treated with ALT administiration in children with cancer between January 2015 and May 2019 were reviewed. Patients characteristics, laboratory and clinical findings, treatments, outcome of ALT, recurrences and reinfections were recorded. Patients with successful and unsuccessful ALT outcomes were compared in order to identify the risk factors for ALT failure. Results. Sixteen eligible CRBSI treated with adjunctive ALT were identified. The most common pathogens were coagulase negative staphylococci (8/16, 50%). Treatment failure was observed in 31.2% (5/16). Younger age alone was an independent risk factor for treatment failure (0.9 vs 6.8 years, p = 0.038). Recurrence and reinfection rates were 23.1% and 16.7%. Mild bleeding occured in two cases (12.5%) and occlusion causing catheter removal was seen in one (6.3%). Conclusions. ALT was found to be a safe modality with a success rate of 68.8% in children with cancer at our center and younger age was an independent risk factor for treatment failure. Future studies with larger sample sizes are needed to determine the factors affecting the ALT outcome, especially in childhood malignancies.