Multimodal classification of molecular subtypes in pediatric acute lymphoblastic leukemia.

Genomic analyses have redefined the molecular subgrouping of pediatric acute lymphoblastic leukemia (ALL). Molecular subgroups guide risk-stratification and targeted therapies, but outcomes of recently identified subtypes are often unclear, owing to limited cases with comprehensive profiling and cross-protocol studies. We developed a machine learning tool (ALLIUM) for the molecular subclassification of ALL in retrospective cohorts as well as for up-front diagnostics. ALLIUM uses DNA methylation and gene expression data from 1131 Nordic ALL patients to predict 17 ALL subtypes with high accuracy. ALLIUM was used to revise and verify the molecular subtype of 281 B-cell precursor ALL (BCP-ALL) cases with previously undefined molecular phenotype, resulting in a single revised subtype for 81.5% of these cases. Our study shows the power of combining DNA methylation and gene expression data for resolving ALL subtypes and provides a comprehensive population-based retrospective cohort study of molecular subtype frequencies in the Nordic countries.

Pediatric-type high-grade neuroepithelial tumors with CIC gene fusion share a common DNA methylation signature.

Pediatric neoplasms in the central nervous system (CNS) show extensive clinical and molecular heterogeneity and are fundamentally different from those occurring in adults. Molecular genetic testing contributes to accurate diagnosis and enables an optimal clinical management of affected children. Here, we investigated a rare, molecularly distinct type of pediatric high-grade neuroepithelial tumor (n = 18), that was identified through unsupervised visualization of genome-wide DNA methylation array data, together with copy number profiling, targeted next-generation DNA sequencing, and RNA transcriptome sequencing. DNA and/or RNA sequencing revealed recurrent fusions involving the capicua transcriptional repressor (CIC) gene in 10/10 tumor samples analyzed, with the most common fusion being CIC::LEUTX (n = 9). In addition, a CIC::NUTM1 fusion was detected in one of the tumors. Apart from the detected fusion events, no additional oncogenic alteration was identified in these tumors. The histopathological review demonstrated a morphologically heterogeneous group of high-grade neuroepithelial tumors with positive immunostaining for markers of glial differentiation in combination with weak and focal expression of synaptophysin, CD56 and CD99. All tumors were located in the supratentorial compartment, occurred during childhood (median age 8.5 years) and typically showed early relapses. In summary, we expand the spectrum of pediatric-type tumors of the CNS by reporting a previously uncharacterized group of rare high-grade neuroepithelial tumors that share a common DNA methylation signature and recurrent gene fusions involving the transcriptional repressor CIC. Downstream functional consequences of the fusion protein CIC::LEUTX and potential therapeutic implications need to be further investigated.

A survey on thromboprophylaxis and coagulation assessment in children and young adults with acute lymphoblastic leukaemia (ALL) in the Nordic and Baltic countries: Different practices of assessment and management.

Patients undergoing treatment for acute lymphoblastic leukaemia (ALL) are at risk of coagulopathy, especially thromboembolism. We conducted a survey on practices in the assessment and management of coagulopathy during the new ALLTogether protocol in 29 (17 paediatric, 12 adult) Nordic and Baltic cancer centres. While 92% of adult centres used thromboprophylaxis with low-molecular-weight heparin, no paediatric centre did. Almost all providers performed baseline coagulation studies, but only 59% continued the assessment. Fibrinogen replacement was conducted in 59%, and antithrombin replacement in 28% of the centres. The survey highlights the need for guidelines in the management of coagulopathy during ALL therapy.

Reduced dose folinic acid rescue after rapid high-dose methotrexate clearance is not associated with increased toxicity in a pediatric cohort.

PURPOSE: Low doses of folinic acid (FA) rescue after high-dose methotrexate (HD-MTX) have been associated with increased toxicity, whereas high doses may be related to a decreased antileukemic effect. The optimal dosage and duration of FA rescue remain controversial. This study was designed to investigate, whether a shorter duration of FA rescue in the setting of rapid HD-MTX clearance is associated with increased toxicity. METHODS: We reviewed the files of 44 children receiving a total of 350 HD-MTX courses during treatment for acute lymphoblastic leukemia according to the NOPHO ALL-2000 protocol. Following a 5 g/m2 HD-MTX infusion, pharmacokinetically guided FA rescue commenced at hour 42. As per local guidelines, the patients received only one or two 15 mg/m2 doses of FA in the case of rapid MTX clearance (serum MTX ≤ 0.2 µmol/L at hour 42 or hour 48, respectively). Data on MTX clearance, FA dosing, inpatient time, and toxicities were collected. RESULTS: Rapid MTX clearance was observed in 181 courses (51.7%). There was no difference in the steady-state MTX concentration, nephrotoxicity, hepatotoxicity, neutropenic fever, or neurotoxicity between courses followed by rapid MTX clearance and those without. One or two doses of FA after rapid MTX clearance resulted in a 7.8-h shorter inpatient time than if a minimum of three doses of FA would have been given. CONCLUSION: A pharmacokinetically guided FA rescue of one or two 15 mg/m2 doses of FA following HD-MTX courses with rapid MTX clearance results in a shorter hospitalization without an increase in toxic effects.

Bisphosphonate treatment in children with acute lymphoblastic leukemia and osteonecrosis - radiological and clinical findings in a national cohort.

Background: Osteonecrosis (ON) is a recognized complication of childhood ALL, but its optimal management remains unestablished. This study evaluated the effect of bisphosphonate (BP) treatment on the evolution of ON lesions in childhood ALL.Material and Methods: We included a national cohort of ALL patients diagnosed with symptomatic ON before 18 years of age and treated with BPs (N = 10; five males). Patients were followed both clinically and with serial MRIs. ON lesions were graded according to the Niinimäki classification.Results: The 10 patients had a total of 55 ON lesions. The median age was 13.3 years at ALL diagnosis and 14.8 years at ON diagnosis. Four patients had received HSCT before the ON diagnosis. BPs used were pamidronate (N = 7), alendronate (N = 2) and ibandronate (N = 1). The duration of BP treatment varied between 4 months and 4 years. In 4/10 patients, BP treatment was given during the chemotherapy. BPs were well-tolerated, with no severe complications or changes in kidney function. At the end of follow up 13/55 (24%) ON lesions were completely healed both clinically and radiographically; all these lesions were originally graded 3 or less. In contrast, ON lesions originally classified as grade 5 (joint destruction; N = 4) remained at grade 5. All grade 5 hip joint lesions needed surgical treatment. During BP treatment, the pain was relieved in 7/10 patients. At the end of follow-up, none of the patients reported severe or frequent pain.Conclusion: BP treatment was safe and seemed effective in relieving ON-induced pain in childhood ALL. After articular collapse (grade 5) lesions did not improve with BP treatment. Randomized controlled studies are needed to further elucidate the role of BPs in childhood ALL-associated ON.

Asymptomatic Right Atrial Thrombosis After Acute Lymphoblastic Leukemia Treatment.

Right atrial thrombosis is a rare, but potentially serious complication of acute lymphoblastic leukemia treatment. We conducted a retrospective multicenter study to assess the incidence, treatment, and outcome of asymptomatic right atrial thrombosis detected at routine echocardiography of children after acute lymphoblastic leukemia treatment in the Nordic and Baltic countries. Eleven (2.7%, 95% confidence interval, 1.4-4.9) of 406 patients had asymptomatic right atrial thrombosis, ranging from 10 to 25 mm at detection. Three patients were treated with anticoagulation. None of the thromboses affected cardiac function, and they showed neither sign of progress nor spontaneous or treatment-related regress at follow-up.

Randomized controlled and double-blinded study of Caphosol versus saline oral rinses in pediatric patients with cancer.

BACKGROUND: Oral mucositis (OM) is a significant side effect of cancer treatment. The purpose of this study was to compare topically administered Caphosol to saline rinses in the prevention of mucositis in pediatric cancer patients. PROCEDURE: A controlled, double-blinded, and randomized clinical crossover study recruited patients between 2 to 17.99 years of age who were diagnosed with a malignancy and were receiving either high-dose methotrexate (≥1 g/m2 ), anthracycline, or cisplatin chemotherapy (NCT0280733). All patients received two 7-day cycles of the mouth rinses; that is, one cycle of Caphosol and one cycle of saline in a randomized order. Oral changes and symptoms were evaluated using the World Health Organisation (WHO) toxicity scale and the Children's International Mucositis Evaluation Scale (ChIMES). The primary endpoint was the frequency and severity of OM and oral symptoms. RESULTS: A total of 56 patients were recruited to the study, of whom 45 were randomized with a median age of 6.5 years (range 2.1-17.1 years). No cases of severe OM were observed. Grade ≥ 3 oral symptoms were present at least once in six (13%) patients during the Caphosol cycle and 13 (29%) patients during the saline cycle (P = .12). The peak of symptom scores was evident at around day 4-7 after administration of the chemotherapy with no marked differences between the rinse solutions. Multivariable regression analysis did not indicate a benefit of using Caphosol over the saline solution. CONCLUSIONS: No difference in prevention of oral mucositis was observed between the use of Caphosol or saline rinses.

Metronomic therapy can increase quality of life during paediatric palliative cancer care, but careful patient selection is essential.

AIM: Children with refractory or high-risk malignancies frequently suffer from poor quality of life during palliative care. This study explored the effect of metronomic drug administration on survival and quality of life in paediatric patients with various refractory or high-risk tumours. METHODS: We treated 17 patients with a maintenance therapy that consisted of metronomic thalidomide, etoposide and celecoxib. The endpoints of the study were overall and progression-free survival, changes in the Karnofsky-Lansky scores from baseline to the end of the study therapy and radiological responses. RESULTS: The median overall survival after the start of the study therapy was 6.2 months (range 2.0-57.7), and the six-, 12- and 24-month survival rates were 59%, 18% and 18%, respectively. The median progression-free survival was 3.2 months (range 0.3-17.8). The Karnofsky-Lansky scores increased significantly during the study therapy (p = 0.02), with 35% of the patients having a transient improvement in their clinical status. Radiologically, one partial response and two disease stabilisations were encountered. Grade III-V adverse events occurred in 76% of the patients. CONCLUSION: Metronomic therapy may increase the quality of life during palliative care for childhood cancer, but requires careful patient selection to minimise the risk of serious adverse events.