Mehmet Fatih Orhan

Purpose: This study aimed to retrospectively evaluate the audiological monitoring of ototoxicity developing in pediatric oncology patients receiving platinum-based chemotherapy. Methods: This retrospective study included 14 patients aged 1 month to 18 years who received platinum-based chemotherapy at the pediatric hematology/oncology clinic between 2015 and 2023 and had pre- and post-treatment audiometric evaluations. Audiometric evaluations were performed in the 250 to 6000 Hz frequency range, and hearing loss was classified according to American Speech-Language-Hearing Association criteria. Results: A general increase in hearing thresholds was observed post-treatment, with the magnitude varying by frequency. While significant changes were detected in low and midfrequencies, the most pronounced increase was observed in high frequencies (4000 to 6000 Hz), and the effect size was large at these frequencies. In the assessment of high-frequency hearing loss, 85.7% of patients had hearing loss. When comparing low and high frequencies, the increase in hearing thresholds was significantly greater at high frequencies. In comparisons between the right and left ears, a tendency toward greater hearing loss was observed in the left ear; however, this difference was not statistically significant. Conclusion: Platinum-based chemotherapy may be associated with clinically relevant hearing threshold shifts in pediatric oncology patients, particularly at high frequencies. Regular audiological monitoring is important for the early identification and management of hearing loss.

Aim Acute appendicitis is a common surgical emergency in children that may cause serious complications if not diagnosed early. This study aimed to evaluate urinary levels of Neutrophil Gelatinase-Associated Lipocalin, L-Fatty Acid-Binding Protein, and I-Fatty Acid-Binding Protein in pediatric patients with acute appendicitis and to investigate their relationships with other biochemical parameters and their possible prognostic value. Methods The study included fifty-four children diagnosed with acute appendicitis and sixty-four healthy controls. Complete blood count, high-sensitivity C-reactive protein, procalcitonin, erythrocyte sedimentation rate, bilirubin, albumin, total protein, full urinalysis, and urinary levels of creatinine, Neutrophil Gelatinase-Associated Lipocalin, L-Fatty Acid-Binding Protein, and I-Fatty Acid-Binding Protein were measured and compared between the two groups. Results There were no significant differences in urinary Neutrophil Gelatinase-Associated Lipocalin, L-Fatty Acid-Binding Protein, creatinine, urea, or uric acid levels between children with acute appendicitis and healthy controls (p>0.05). However, I-Fatty Acid-Binding Protein, sodium, potassium, and albumin levels were significantly lower in patients, while high-sensitivity C-reactive protein and procalcitonin levels were significantly higher (p<0.05). Each 1 milligram per liter increase in high-sensitivity C-reactive protein was associated with a 2.36-fold higher risk of appendicitis (p=0.003), whereas each one milliequivalent per deciliter increase in potassium was related to a 0.001-fold lower risk (p=0.002). Conclusion These biomarkers may indicate intestinal inflammation and support the diagnosis of acute appendicitis; however, none appear adequate to be used alone as a definitive diagnostic test.

Objective: In this study, we investigated the initial serum immunoglobulin and lymphocyte subset levels of children with immune thrombocytopenia (ITP), and their association with treatment response. Methods: Thirty children with ITP were retrospectively analyzed. Immunoglobulin isotypes, IgG subtypes, and lymphocyte subset levels in the patients were compared with those of the age- and sex-matched control group and age-appropriate reference values. In addition, we investigated the relationship between immunological parameters and treatment responses. Results: There was no statistically significant difference between the patient and control groups regarding immunoglobulin isotype and IgG subtype levels. However, IgG levels were below normal limits in 10 (33.3%) patients, and IgA and IgG2 levels were low in 2 patients with normal IgG levels. Younger age and low IgG level at diagnosis were associated with an increased treatment response on day 7. Conclusion: Serum immunoglobulin levels at the time of diagnosis can help predict treatment response in the early period and detect subclinical immunodeficiency in children with acute ITP.

Acute lymphoblastic leukemia (ALL) is a critical type of cancer affecting white blood cell development. It is characterized by the disruption of normal stem cell maturation processes or the excessive proliferation of leukemic cells. As the most common childhood cancer, ALL is a significant health problem requiring continuous clinical monitoring. A major challenge in diagnosing the disease stems from the non-specific nature of the initial symptoms. Common symptoms, such as fever, fatigue, headache, weight loss, and musculoskeletal disorders, can mimic many diseases, making diagnostic accuracy challenging. This ambiguity leads to delayed diagnosis and negatively impacts treatment success. Although the incidence of leukemia has increased in recent years, advances in medical technology have shown promising results in reducing mortality rates. Health information systems play a significant role in this success by facilitating early disease diagnosis. In our research, two different image enhancement methods were developed to highlight the characteristics of blast cells, a critical indicator for the diagnosis of ALL. Three image groups were evaluated: unprocessed original images and two different processed image sets (versions 1 and 2). Classification performed using the MobileNetv2 transfer learning framework achieved accuracy rates of 85%, 90%, and 89% on the test dataset, respectively. To enhance diagnostic reliability beyond single-model performance, an ensemble architecture combining eight different transfer learning networks was created. This optimized ensemble model, using images enhanced with the high-performing version 1 filter, achieved approximately 90% classification accuracy. This result represents a significant advancement in AI-assisted hematological image interpretation.

Eltrombopag (EPAG) added to standard immunosuppressive therapy (IST) was associated with higher overall (OR) and complete response (CR) rates in patients with treatment-naïve severe aplastic anemia (SAA) in adults, but the clinical evidence on the efficacy of EPAG in children with acquired aplastic anemia is limited and controversial. We compared the efficacy and safety of EPAG combined with IST (n=38) versus IST alone (n=57) as a front-line treatment for pediatric patients with SAA. The EPAG+IST group had higher CR and OR rates at 3 and 6 months, although 1-year OR, CR, and partial response (PR) rates showed no significant difference between two groups. Older age at diagnosis (>8.95 years) was associated in the EPAG+IST group with higher OR rates at 6 months and 1-year (p=0.007, p=0.005, respectively). The addition of EPAG to IST did not demonstrate superiority over IST alone in terms of overall survival (OS) and event-free survival (EFS) in this study; with 1-year EFS of 81.1% for EPAG+IST and 71.3% for IST, and with 1-year OS of 89.2% vs. 80.4%. Eltrombopag induced a faster response compared to those receiving IST alone without increasing toxic effects, but EPAG does not confer additional benefits regarding OS or relapse rates in children. Notably, older age at diagnosis in the EPAG+IST group was significantly associated with improved response rates.

Objective: B-cell Non-Hodgkin Lymphoma (B-NHL) is an aggressive malignancy in children requiring prompt multidisciplinary management. This retrospective cohort study aims to evaluate the clinical characteristics, treatment outcomes, and impact of rituximab (RTX) in pediatric B-NHL patients. Methods: We retrospectively analyzed 62 pediatric B-NHL patients treated at tertiary centers. Patient demographics, clinical presentation, histopathological subtypes, disease stage, treatment regimens, and survival outcomes were assessed. Event-free survival (EFS) and overall survival (OS) rates were analyzed based on lactate dehydrogenase (LDH) levels and RTX administration. Results: The mean age at diagnosis was 8.73±4.3 years, with a male predominance (79%). The most common histological subtype was Burkitt lymphoma (BL) (53.2%), followed by diffuse large B-cell lymphoma (DLBCL) (33.8%). Advanced-stage disease (III-IV) was observed in 74.1% of cases. RTX was administered in 72.5% of patients, with a mean of 5.1±2.7 doses. Febrile neutropenia (FEN) was noted in 74.1%, with intensive care unit (ICU) admission required for seven patients. Mortality was observed in 12 (19.3%) patients, including all patients with primary immunodeficiency (PID). The 5-year EFS for the entire cohort was 67.2%, and OS was 81.3%. Patients with LDH 400 U/L (EFS: 49.6%, OS: 70.7%; p=0.004 and p=0.015, respectively). In RTX-treated patients without PID, EFS was 76.5% versus 73.2% in those without RTX, but the difference was not statistically significant (p=0.53). Conclusions: Although not statistically significant, EFS was found to be higher in the RTX-treated group, suggesting that adding RTX to standard chemotherapy regimens may improve survival, particularly for high-risk patients, though its benefit in low-risk cases remains uncertain. Despite improved survival, patients with PID had poor outcomes, likely due to increased infections and disseminated disease. Risk-adapted, targeted treatment strategies are essential for optimizing outcomes in pediatric B-NHL. Further large-scale, randomized controlled trials are needed to confirm the efficacy of RTX in different risk groups and to optimize treatment regimens for pediatric B-NHL.

Background. Microbiologic confirmation of respiratory tract infections gained importance during the coronavirus disease 2019 (COVID-19) pandemic. This study retrospectively evaluated seasonal distribution, clinical presentation, and complications of respiratory viral infections (RVIs) other than COVID-19 in children with cancer during and after the pandemic lockdown. Methods. Two hundred and sixty-five inpatient and outpatient RVI episodes in 219 pediatric cancer patients confirmed by multiplex reverse transcriptase polymerase chain reaction (RT-PCR) panels from 13 centers were enrolled. Results. Eighty-six (32.5%) of the total 265 episodes occurred in 16 months corresponding to the lockdowns in Türkiye, and the remaining 67.5% in 10 months thereafter. Human rhinovirus/enterovirus (hRE) (48.3%) was the most common agent detected during and after lockdown. Parainfluenza virus (PIV) (23.0%), influenza virus (9.8%), and respiratory syncytial virus (RSV) (9.1%) were the other common agents. The 28.7% of episodes were lower respiratory tract infections (LRTIs), and complications and mortality were higher than upper respiratory tract infections (URTIs) (25.0% vs 5.3%). Bacteremia was identified in 11.5% of culture-drawn episodes. Treatment delay in one-third and death within four weeks after RVI in 4.9% of episodes were observed. Conclusion. During the pandemic, fewer episodes of RVIs occurred during the lockdown period. Respiratory viruses may cause complications, delays in treatment, and even death in children with cancer. Therefore, increased awareness of RVIs and rapid detection of respiratory viruses will benefit the prevention and, in some cases, abrupt supportive and some antiviral treatment of RVI in children with cancer.