Chemotherapy-related toxicities follow a typical pattern in children treated for acute lymphoblastic leukaemia

AIM

Acute lymphoblastic leukaemia (ALL) therapy has been associated with a significant burden of toxicities. The aim of this study was to describe the full spectrum of toxic effects associated with childhood ALL.

METHODS

Toxicity-related data were collected from the Nordic Society of Paediatric Haematology and Oncology (NOPHO) ALL-2008 toxicity registry, in which data on 19 clinically relevant toxicities were registered during ALL treatment, and from patient medical records. All patients treated according to the NOPHO ALL-2008 protocol in Oulu University Hospital between 2008 and 2020 were included in the study.

RESULTS

The cohort consisted of 73 patients, 38 of whom were male. Mean age at diagnosis was 6.6 ± 4.2 (range 1.4-16.0) years. All but one of the patients developed at least one treatment-related toxicity and more than half had multiple toxicities. Female sex and older age were associated with a higher tendency towards toxicity. The most common toxicity was vincristine-induced peripheral neuropathy, which was observed in 70 patients. Most toxicities were moderate or severe, but even mild toxicities often affected leukaemia treatment.

CONCLUSION

Moderate and severe treatment-related toxicities are common, and most toxicities occur in a typical pattern in relation to the treatment phases.

Previous cancers in women diagnosed with premature ovarian insufficiency: A nationwide population-based case-control study

INTRODUCTION

To investigate the occurrence of previous cancer diagnoses in women suffering from premature ovarian insufficiency (POI) and compare it with the general population, shedding light on the association between cancer, cancer treatments, and POI.

MATERIAL AND METHODS

We conducted a nationwide case-control study based on registry data from various sources, including the Social Insurance Institution, Finnish Population Information System, and Finnish Cancer Registry spanning from 1953 to 2018. Our participants comprised all women in Finland who, between 1988 and 2017, received hormone replacement therapy reimbursement for ovarian insufficiency before the age of 40 years (n = 5221). Controls, matched in terms of age and municipality of residence, were selected from the Finnish Population Information System (n = 20 822). Our main exposure variable was a history of cancer diagnosis preceding the diagnosis of POI. We analyzed odds ratios (OR) to compare the prevalence of previous cancers in women with POI with that in controls, stratifying results based on cancer type, age at cancer diagnosis, and the time interval between cancer diagnosis and POI. We also assessed changes in OR for previous cancer diagnoses over the follow-up period.

RESULTS

Out of the women diagnosed with POI, 21.9% had previously been diagnosed with cancer, resulting in an elevated OR of 36.5 (95% confidence interval [CI] 30.9 to 43.3) compared with 0.8% of the controls. The risk of developing POI was most pronounced during the first 2 years following a cancer diagnosis, with an OR of 103 (95% CI 74.1 to 144). Importantly, this risk remained elevated even when the time interval between cancer and POI exceeded 10 years, with an OR of 5.40 (95% CI 3.54 to 8.23).

CONCLUSIONS

This study reveals that 21.9% of women with POI have a history of cancer, making the prevalence of cancer among these women 27.5 times higher than age-matched controls in the Finnish population. The risk of developing POI is most substantial in the first 2 years following a cancer diagnosis. These findings underscore the role of cancer treatments as an etiological factor for POI and emphasize the importance of recognizing the risk of POI in cancer survivors for early diagnosis and intervention.

DNA polymerase gamma variants and hepatotoxicity during maintenance therapy of childhood acute lymphoblastic leukemia: is there a causal relationship?

Hepatotoxicity is a frequent complication during maintenance therapy of acute lymphoblastic leukemia (ALL) with 6-mercaptopurine and methotrexate. Elevated levels of methylated 6-mercaptopurine metabolites (MeMP) are associated with hepatotoxicity. However, not all mechanisms are known that lead to liver failure in patients with ALL. Variants in the POLG gene, which encodes the catalytic subunit of mitochondrial DNA polymerase gamma (POLG1), have been related to drug-induced hepatotoxicity, for example, by sodium valproate. The association of common POLG variants with hepatotoxicity during maintenance therapy was studied in 34 patients with childhood ALL. Of the screened POLG variants, four different variants were detected in 12 patients. One patient developed severe hepatotoxicity without elevated MeMP levels and harbored a heterozygous POLG p.G517V variant, which was not found in the other patients.

The clinical picture of ERCC6L2 disease: from bone marrow failure to acute leukemia

Biallelic germ line excision repair cross-complementing 6 like 2 (ERCC6L2) variants strongly predispose to bone marrow failure (BMF) and myeloid malignancies, characterized by somatic TP53-mutated clones and erythroid predominance. We present a series of 52 subjects (35 families) with ERCC6L2 biallelic germ line variants collected retrospectively from 11 centers globally, with a follow-up of 1165 person-years. At initial investigations, 32 individuals were diagnosed with BMF and 15 with a hematological malignancy (HM). The subjects presented with 19 different variants of ERCC6L2, and we identified a founder mutation, c.1424delT, in Finnish patients. The median age of the subjects at baseline was 18 years (range, 2-65 years). Changes in the complete blood count were mild despite severe bone marrow (BM) hypoplasia and somatic TP53 mutations, with no significant difference between subjects with or without HMs. Signs of progressive disease included increasing TP53 variant allele frequency, dysplasia in megakaryocytes and/or erythroid lineage, and erythroid predominance in the BM morphology. The median age at the onset of HM was 37.0 years (95% CI, 31.5-42.5; range, 12-65 years). The overall survival (OS) at 3 years was 95% (95% CI, 85-100) and 19% (95% CI, 0-39) for patients with BMF and HM, respectively. Patients with myelodysplastic syndrome or acute myeloid leukemia with mutated TP53 undergoing hematopoietic stem cell transplantation had a poor outcome with a 3-year OS of 28% (95% CI, 0-61). Our results demonstrated the importance of early recognition and active surveillance in patients with biallelic germ line ERCC6L2 variants.

Changes in body mass index during treatment of childhood acute lymphoblastic leukemia with the Nordic ALL2008 protocol

OBJECTIVES

Children with acute lymphoblastic leukemia (ALL) have a tendency to gain weight during treatment. As overweight and obesity associate with health problems, prophylactic interventions are warranted. Therefore, it is important to identify the children most prone to gain weight.

METHODS

Patients aged 2.0-17.9 years at ALL diagnosis were identified from the NOPHO ALL2008 registry. Registry data was complemented with height and weight at the end of therapy from questionnaires. Body mass index (BMI) was classified according to international age- and sex-adjusted International Obesity Task Force BMI cut-offs. BMI values were transformed into standard deviation scores (SDS) to calculate the difference in BMISDS during treatment.

RESULTS

Data on BMI change were available for 765 children. Overweight and obesity doubled during treatment: 9.7% were overweight and 2.1% obese at diagnosis and 21.8% and 5.4% at the end of therapy, respectively. The mean BMISDS change was +0.64. Younger (2.0-5.9 years) and healthy weight children were most prone to become overweight (mean change in BMI SDS +0.85 and + 0.65, respectively).

CONCLUSIONS

Younger children (2.0-5.9 years) with healthy weight at diagnosis were most prone to becoming overweight and therefore are an important group to target while considering interventions.

Does minimal central nervous system involvement in childhood acute lymphoblastic leukemia increase the risk for central nervous system toxicity?

Central nervous system (CNS) involvement in childhood acute lymphoblastic leukemia (ALL) implicates enhanced intrathecal chemotherapy, which is related to CNS toxicity. Whether CNS involvement alone contributes to CNS toxicity remains unclear. We studied the occurrence of all CNS toxicities, seizures, and posterior reversible encephalopathy syndrome (PRES) in children with ALL without enhanced intrathecal chemotherapy with CNS involvement (n = 64) or without CNS involvement (n = 256) by flow cytometry. CNS involvement increased the risk for all CNS toxicities, seizures, and PRES in univariate analysis and, after adjusting for induction therapy, for seizures (hazard ratio [HR] = 3.33; 95% confidence interval [CI]: 1.26-8.82; p = 0.016) and PRES (HR = 4.85; 95% CI: 1.71-13.75; p = 0.003).

Thiopurine Enhanced ALL Maintenance (TEAM): study protocol for a randomized study to evaluate the improvement in disease-free survival by adding very low dose 6-thioguanine to 6-mercaptopurine/methotrexate-based maintenance therapy in pediatric and adult patients (0-45 years) with newly diagnosed B-cell precursor or T-cell acute lymphoblastic leukemia treated according to the intermediate risk-high group of the ALLTogether1 protocol

Background

A critical challenge in current acute lymphoblastic leukemia (ALL) therapy is treatment intensification in order to reduce the relapse rate in the subset of patients at the highest risk of relapse. The year-long maintenance phase is essential in relapse prevention. The Thiopurine Enhanced ALL Maintenance (TEAM) trial investigates a novel strategy for ALL maintenance.

Methods

TEAM is a randomized phase 3 sub-protocol to the ALLTogether1 trial, which includes patients 0–45 years of age with newly diagnosed B-cell precursor or T-cell ALL, and stratified to the intermediate risk-high (IR-high) group, in 13 European countries. In the TEAM trial, the traditional methotrexate (MTX)/6-mercaptopurine (6MP) maintenance backbone (control arm) is supplemented with low dose (2.5–12.5 mg/m²/day) oral 6-thioguanine (6TG) (experimental arm), while the starting dose of 6MP is reduced from 75 to 50 mg/m²/day. A total of 778 patients will be included in TEAM during ~ 5 years. The study will close when the last included patient has been followed for 5 years from the end of induction therapy. The primary objective of the study is to significantly improve the disease-free survival (DFS) of IR-high ALL patients by adding 6TG to 6MP/MTX-based maintenance therapy. TEAM has 80% power to detect a 7% increase in 5-year DFS through a 50% reduction in relapse rate. DFS will be evaluated by intention-to-treat analysis. In addition to reducing relapse, TEAM may also reduce hepatotoxicity and hypoglycemia caused by high levels of methylated 6MP metabolites. Methotrexate/6MP metabolites will be monitored and low levels will be reported back to clinicians to identify potentially non-adherent patients.

Discussion

TEAM provides a novel strategy for maintenance therapy in ALL with the potential of improving DFS through reducing relapse rate. Potential risk factors that have been considered include hepatic sinusoidal obstruction syndrome/nodular regenerative hyperplasia, second cancer, infection, and osteonecrosis. Metabolite monitoring can potentially increase treatment adherence in both treatment arms.

Trial registration

EudraCT, 2018–001795-38. Registered 2020-05-15,

Clinicaltrials.gov, NCT04307576. Registered 2020-03-13, https://clinicaltrials.gov/ct2/show/NCT04307576

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09522-3.

Can Machine Learning Models Predict Asparaginase-associated Pancreatitis in Childhood Acute Lymphoblastic Leukemia

Asparaginase-associated pancreatitis (AAP) frequently affects children treated for acute lymphoblastic leukemia (ALL) causing severe acute and persisting complications. Known risk factors such as asparaginase dosing, older age and single nucleotide polymorphisms (SNPs) have insufficient odds ratios to allow personalized asparaginase therapy. In this study, we explored machine learning strategies for prediction of individual AAP risk. We integrated information on age, sex, and SNPs based on Illumina Omni2.5exome-8 arrays of patients with childhood ALL (N=1564, 244 with AAP 1.0 to 17.9 yo) from 10 international ALL consortia into machine learning models including regression, random forest, AdaBoost and artificial neural networks. A model with only age and sex had area under the receiver operating characteristic curve (ROC-AUC) of 0.62. Inclusion of 6 pancreatitis candidate gene SNPs or 4 validated pancreatitis SNPs boosted ROC-AUC somewhat (0.67) while 30 SNPs, identified through our AAP genome-wide association study cohort, boosted performance (0.80). Most predictive features included rs10273639 (PRSS1-PRSS2), rs10436957 (CTRC), rs13228878 (PRSS1/PRSS2), rs1505495 (GALNTL6), rs4655107 (EPHB2) and age (1 to 7 y). Second AAP following asparaginase re-exposure was predicted with ROC-AUC: 0.65. The machine learning models assist individual-level risk assessment of AAP for future prevention trials, and may legitimize asparaginase re-exposure when AAP risk is predicted to be low.

Acute central nervous system toxicity during treatment of pediatric acute lymphoblastic leukemia: phenotypes, risk factors and genotypes

Central nervous system (CNS) toxicity is common at diagnosis and during treatment of pediatric acute lymphoblastic leukemia (ALL). We studied CNS toxicity in 1 464 children aged 1.0-17.9 years, diagnosed with ALL and treated according to the Nordic Society of Pediatric Hematology and Oncology ALL2008 protocol. Genome-wide association studies (GWAS), and a candidate single-nucleotide polymorphism (SNP; n=19) study were performed in 1 166 patients. Findings were validated in an Australian independent cohort of children with ALL (n=797) where two phenotypes were evaluated: diverse CNS toxicities (n=103) and methotrexate-related CNS toxicity (n=48). In total, 135/1 464 (9.2%) patients experienced CNS toxicity with cumulative incidence of 8.7% (95% CI: 7.31-10.20) at 12 months from diagnosis. Patients aged ≥10 years had higher risk of CNS toxicity than younger patients (16.3% vs 7.4%; p.

Obesity as a predictor of treatment-related toxicity in children with acute lymphoblastic leukaemia

Obesity is associated with poor outcomes in childhood acute lymphoblastic leukaemia (ALL). We explored whether severe treatment-related toxicity and treatment delays could explain this observation. This study included 1 443 children aged 2·0-17·9 years with ALL treated with the Nordic Society of Pediatric Haematology and Oncology (NOPHO) ALL2008 non-high-risk protocol. Prospective treatment-related toxicities registered every three-month interval were used. Patients were classified according to sex- and age-adjusted international childhood cut-off values, corresponding to adult body mass index: underweight, <17 kg/m² ; healthy weight, 17 to <25 kg/m² ; overweight, 25 to <30 kg/m² ; and obese, ≥30 kg/m² . Obese children had a higher incidence rate ratio (IRR) for severe toxic events {IRR: 1·55 [95% confidence interval (CI) 1·07-2·50]}, liver and kidney failures, bleeding, abdominal complication, suspected unexpected severe adverse reactions and hyperlipidaemia compared with healthy-weight children. Obese children aged ≥10 years had increased IRRs for asparaginase-related toxicities compared with healthy-weight older children: thromboses [IRR 2·87 (95% CI 1·00-8·21)] and anaphylactic reactions [IRR 7·95 (95% CI 2·15-29·37)] as well as higher risk for truncation of asparaginase [IRR 3·54 (95% CI 1·67-7·50)]. The high prevalence of toxicity and a higher risk of truncation of asparaginase may play a role in the poor prognosis of obese children aged ≥10 years with ALL.

Bone mineral density surveillance for childhood, adolescent, and young adult cancer survivors: evidence-based recommendations from the International Late Effects of Childhood Cancer Guideline Harmonization Group

Childhood, adolescent, and young adult cancer survivors are at increased risk of reduced bone mineral density. Clinical practice surveillance guidelines are important for timely diagnosis and treatment of these survivors, which could improve bone mineral density parameters and prevent fragility fractures. Discordances across current late effects guidelines necessitated international harmonisation of recommendations for bone mineral density surveillance. The International Late Effects of Childhood Cancer Guideline Harmonization Group therefore established a panel of 36 experts from ten countries, representing a range of relevant medical specialties. The evidence of risk factors for very low and low bone mineral density and fractures, surveillance modality, timing of bone mineral density surveillance, and treatment of very low and low bone mineral density were evaluated and critically appraised, and harmonised recommendations for childhood, adolescent, and young adult cancer survivors were formulated. We graded the recommendations based on the quality of evidence and balance between potential benefits and harms. Bone mineral density surveillance is recommended for survivors treated with cranial or craniospinal radiotherapy and is reasonable for survivors treated with total body irradiation. Due to insufficient evidence, no recommendation can be formulated for or against bone mineral density surveillance for survivors treated with corticosteroids. This surveillance decision should be made by the survivor and health-care provider together, after careful consideration of the potential harms and benefits and additional risk factors. We recommend to carry out bone mineral density surveillance using dual-energy x-ray absorptiometry at entry into long-term follow-up, and if normal (Z-score > -1), repeat when the survivor is aged 25 years. Between these measurements and thereafter, surveillance should be done as clinically indicated. These recommendations facilitate evidence-based care for childhood, adolescent, and young adult cancer survivors internationally.

Skeletal adverse events in childhood cancer survivors: An Adult Life after Childhood Cancer in Scandinavia cohort study

The dynamic growth of the skeleton during childhood and adolescence renders it vulnerable to adverse effects of cancer treatment. The lifetime risk and patterns of skeletal morbidity have not been described in a population-based cohort of childhood cancer survivors. A cohort of 26 334 1-year cancer survivors diagnosed before 20 years of age was identified from the national cancer registries of Denmark, Finland, Iceland and Sweden as well as a cohort of 127 531 age- and sex-matched comparison subjects randomly selected from the national population registries in each country. The two cohorts were linked with data from the national hospital registries and the observed numbers of first-time hospital admissions for adverse skeletal outcomes among childhood cancer survivors were compared to the expected numbers derived from the comparison cohort. In total, 1987 childhood cancer survivors had at least one hospital admission with a skeletal adverse event as discharge diagnosis, yielding a rate ratio (RR) of 1.35 (95% confidence interval, 1.29-1.42). Among the survivors, we observed an increased risk for osteonecrosis with a RR of 25.9 (15.0-44.5), osteoporosis, RR 4.53 (3.28-6.27), fractures, RR 1.27 (1.20-1.34), osteochondropathies, RR 1.57 (1.28-1.92) and osteoarthrosis, RR 1.48 (1.28-1.72). The hospitalization risk for any skeletal adverse event was higher among survivors up to the age of 60 years, but the lifetime pattern was different for each type of skeletal adverse event. Understanding the different lifetime patterns and identification of high-risk groups is crucial for developing strategies to optimize skeletal health in childhood cancer survivors.

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.

Supportive Care During Pediatric Hematopoietic Stem Cell Transplantation: Prevention of Infections. A Report From Workshops on Supportive Care of the Paediatric Diseases Working Party (PDWP) of the European Society for Blood and Marrow Transplantation (EBMT)

Specific protocols define eligibility, conditioning, donor selection, graft composition and prophylaxis of graft vs. host disease for children and young adults undergoing hematopoietic stem cell transplant (HSCT). However, international protocols rarely, if ever, detail supportive care, including pharmaceutical infection prophylaxis, physical protection with face masks and cohort isolation or food restrictions. Supportive care suffers from a lack of scientific evidence and implementation of practices in the transplant centers brings extensive restrictions to the child's and family's daily life after HSCT. Therefore, the Board of the Pediatric Diseases Working Party (PDWP) of the European Society for Blood and Marrow Transplantation (EBMT) held a series of dedicated workshops since 2017 with the aim of initiating the production of a set of minimal recommendations. The present paper describes the consensus reached within the field of infection prophylaxis.

Impact of body mass index on relapse in children with acute lymphoblastic leukemia treated according to Nordic treatment protocols

Objectives

High body mass index (BMI) is associated with poorer survival in childhood acute lymphoblastic leukemia (ALL), but the actual impact on the risk of relapse still needs to be clarified. We evaluated the impact of BMI at diagnosis on the risk of relapse in children with ALL treated according to Nordic Society of Paediatric Haematology and Oncology (NOPHO) protocols.

Method

In a multicenter study, we collected data on BMI at diagnosis and outcome of 2558 children aged 2.0‐17.9 years diagnosed between 1992 and 2016. Patients were divided into four groups according to International Obesity Task Force (IOTF) childhood BMI cut‐offs: underweight, <17; healthy weight, 17‐25; overweight, 25‐30; and obese, ≥30 kg/m².

Results

In Cox multivariate regression analyses, an increased risk of relapse was observed in children aged 10‐17.9 years with unhealthy BMI at diagnosis (underweight hazard ratio HR: 2.90 [95% confidence interval: 1.24‐6.78], P = .01; overweight, HR: 1.95 [1.11‐3.43], P = .02, and obese HR: 4.32 [95% 2.08‐8.97], P < .001), compared to children with healthy weight. BMI had no impact on relapse in children under 10 years of age.

Conclusion

High BMI, and especially obesity at diagnosis, is an independent adverse prognostic factor for relapse in older children with ALL.

Seizures during treatment of childhood acute lymphoblastic leukemia: A population-based cohort study

BACKGROUND

Seizures are common in children with acute lymphoblastic leukemia (ALL). As ALL survival rates are improving, the challenge to minimize treatment related side effects and late sequelae rises. Here, we studied the frequency, timing, etiology and risk factors of seizures in ALL patients.

METHODS

The study included children aged 1-17.9 years at diagnosis of B-cell-precursor and T cell ALL who were treated according to the Nordic Society of Pediatric Hematology and Oncology (NOPHO) ALL2008 protocol between 2008 and 2015. Detailed patient data were acquired from the NOPHO ALL2008 registry and by review of medical records.

RESULTS

Seizures occurred in 81/1464 (5.5%) patients. The cumulative incidence of seizures at one months was 1.7% (95% CI: 1.2-2.5) and at one year 5.3% (95% CI 4.2-6.5%). Patients aged 10-17.9 years, those with T cell immunophenotype, CNS involvement, or high-risk induction with dexamethasone had higher risk for seizures in univariable analyses. Only age remained a risk factor in multivariable analyses (the cumulative incidence of seizures for patients 10-17.9 years old at one year was 9.0% (95% CI: 6.2-12.9)). Of the 81 patients with seizures, 43 had posterior reversible encephalopathy syndrome (PRES), 15 had isolated seizures, nine had sinus venous thrombosis (SVT), three had stroke-like syndrome, and 11 had other neurotoxicities. Epilepsy diagnosis was reported in totally 11 ALL survivors at last follow up.

CONCLUSION

Seizures are relatively common in ALL patients and occur most often in patients with PRES, SVT, or as an isolated symptom. Older children have higher risk of seizures.

Medulloblastoma, macrocephaly, and a pathogenic germline PTEN variant: Cause or coincidence?

Background

Medulloblastomas (MBs) are a heterogeneous group of childhood brain tumors with four consensus subgroups, namely MB_SHH, MB_WNT, MB_{Group 3}, and MB_{Group 4}, representing the second most common type of pediatric brain cancer after high‐grade gliomas. They suffer from a high prevalence of genetic predisposition with up to 20% of MB_SHH caused by germline mutations in only six genes. However, the spectrum of germline mutations in MB_SHH remains incomplete.

Methods

Comprehensive Next‐Generation Sequencing panels of both tumor and patient blood samples were performed as molecular genetic characterization. The panels cover genes that are known to predispose to cancer.

Results

Here, we report on a patient with a pathogenic germline PTEN variant resulting in an early stop codon p.(Glu7Argfs*4) (ClinVar ID: 480383). The patient developed macrocephaly and MB_SHH, but reached remission with current treatment protocols.

Conclusions

We propose that pathogenic PTEN variants may predispose to medulloblastoma, and show that remission was reached with current treatment protocols. The PTEN gene should be included in the genetic testing provided to patients who develop medulloblastoma at an early age. We recommend brain magnetic resonance imaging upon an unexpected acceleration of growth of head circumference for pediatric patients harboring pathogenic germline PTEN variants.

Correction: Supportive care during pediatric hematopoietic stem cell transplantation: beyond infectious diseases. A report from workshops on supportive care of the Pediatric Diseases Working Party (PDWP) of the European Society for Blood and Marrow Transplantation (EBMT)

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Supportive care during pediatric hematopoietic stem cell transplantation: beyond infectious diseases. A report from workshops on supportive care of the Pediatric Diseases Working Party (PDWP) of the European Society for Blood and Marrow Transplantation (EBMT)

Hematopoietic stem cell transplantation (HSCT) is currently the standard of care for many malignant and nonmalignant blood diseases. As several treatment-emerging acute toxicities are expected, optimal supportive measurements critically affect HSCT outcomes. The paucity of good clinical studies in supportive practices gives rise to the establishment of heterogeneous guidelines across the different centers, which hampers direct clinical comparison in multicentric studies. Aiming to harmonize the supportive care provided during the pediatric HSCT in Europe, the Pediatric Diseases Working Party (PDWP) of the European Society for Blood and Marrow Transplantation (EBMT) promoted dedicated workshops during the years 2017 and 2018. The present paper describes the resulting consensus on the management of sinusoidal obstructive syndrome, mucositis, enteral and parenteral nutrition, iron overload, and emesis during HSCT.

The spectrum of acute central nervous system symptoms during the treatment of childhood acute lymphoblastic leukaemia

BACKGROUND

Children with central nervous system (CNS) toxicity during therapy for acute lymphoblastic leukaemia (ALL) are at risk for treatment modifications, long-term sequelae and even higher mortality. A better understanding of CNS symptoms and their complications improves the potential to prevent and treat them.

METHODS

Patient files from 649 children treated with Nordic Society of Pediatric Hematology and Oncology ALL92 and ALL2000 protocols in Finland were reviewed retrospectively for any acute CNS symptom. Detailed data on symptoms, examinations and treatment of the underlying CNS complications were collected from the medical records. Disease-related and outcome data were retrieved from the Nordic leukaemia registry.

RESULTS

Altogether, 13% (86) of patients with ALL had acute CNS symptoms. Most symptoms (64%) occurred during the first 2 months of therapy. Posterior reversible encephalopathy syndrome was the most frequent complication (4.5%). Cerebrovascular events were diagnosed in 10 cases (1.6%), while methotrexate-related stroke-like syndrome (SLS) was observed in only one patient (0.2%). CNS symptoms due to systemic or unclear conditions, especially sepsis, were important for differential diagnosis. CNS leukaemia was associated with CNS symptoms (hazard ratio [HR] = 4.03; P = .003), and epilepsy was a common sequel of CNS complications (19%).

CONCLUSIONS

Acute CNS symptoms are common during ALL therapy, occurring mainly during the first 2 months of treatment. Patients with CNS leukaemia at diagnosis are at a higher risk for CNS toxicity. Despite intensive CNS-directed methotrexate treatment, SLS was diagnosed extremely rarely in our series.

Predisposition to childhood acute lymphoblastic leukemia caused by a constitutional translocation disrupting ETV6

Pathogenic germline variants in ETV6 have been associated with familial predisposition to thrombocytopenia and hematological malignancies, predominantly childhood B-cell precursor acute lymphoblastic leukemia (BCP-ALL). In addition, overrepresentation of a high hyperdiploid subtype and older age at diagnosis have been reported among sporadic BCP-ALL cases with germline variants in ETV6 We studied a family with 2 second-degree relatives who developed childhood high hyperdiploid BCP-ALL at ages 8 and 12 years, respectively. A constitutional balanced reciprocal translocation t(12;14)(p13.2;q23.1) was discovered in both patients by routine karyotyping at diagnosis and, subsequently, in 7 healthy family members who had not experienced hematological malignancies. No carriers had thrombocytopenia. Whole-genome sequencing confirmed the translocation, resulting in 2 actively transcribed but nonfunctional fusion genes, causing heterozygous loss and consequently monoallelic expression of ETV6 Whole-genome sequencing analysis of the affected female subjects' leukemia excluded additional somatic aberrations in ETV6 and RTN1 as well as shared somatic variants in other genes. Expression studies, performed to confirm decreased expression of ETV6, were not conclusive. We suggest that germline aberrations resulting in monoallelic expression of ETV6 contribute to leukemia susceptibility, whereas more severe functional deficiency of ETV6 is required for developing THC5. To our knowledge, this report is the first of a constitutional translocation disrupting ETV6 causing predisposition to childhood ALL.

A nearly fatal primary Epstein-Barr virus infection associated with low NK-cell counts in a patient receiving azathioprine: a case report and review of literature

Background

Symptomatic primary Epstein-Barr virus infection is a usually self-limiting illness in adolescents. We present a case of an adolescent who had been receiving azathioprine for inflammatory bowel disease for four years and developed a life-threatening primary Epstein-Barr virus infection successfully treated with rituximab.

Case presentation

An 11-year-old girl presented with chronic, bloody diarrhea. Endoscopic biopsies confirmed a diagnosis of chronic ulcerative colitis with features of Crohn’s disease. Azathioprine was initiated after one year due to active colitis. She responded well and remission was achieved. At the age of 16 years she developed a life-threatening Epstein-Barr virus infection including severe multiple organ failure and was critically ill for 4 weeks in the intensive care unit. Natural killer cells were virtually absent in the lymphocyte subset analysis. Azathioprine was stopped on admission. She was initially treated with corticosteroids, acyclovir and intravenous immunoglobulin. Approximately 30 days after admission, she developed signs of severe hepatitis and pneumonitis and received weekly rituximab infusions for 8 weeks. Primary immunodeficiency was excluded by whole exome sequencing in two independent laboratories. Persistent viremia stopped when the natural killer cell count started to rise, approximately 90 days after the cessation of azathioprine.

Conclusions

We found 17 comparable cases in the literature. None of the previous cases reported in the literature, who had been treated with azathioprine and developed either a severe or a fatal Epstein-Barr virus infection, underwent full genetic and prospective immunological workup to rule out known primary immunodeficiencies. Recently, azathioprine has been shown to cause rather specific immunosuppression, resulting in natural killer cell depletion. Our case demonstrates that slow recovery from azathioprine-induced natural killer cell depletion, 3 months after the stopping of azathioprine, coincided with the clearance of viremia and clinical recovery. Finally, our choice of treating the patient with rituximab, as previously used for patients with a severe immunosuppression and Epstein-Barr virus viremia, appeared to be successful in this case. We suggest testing for Epstein-Barr virus serology before starting azathioprine and measuring natural killer cell counts during the treatment to identify patients at risk of developing an unusually severe primary Epstein-Barr virus infection.

Posterior reversible encephalopathy syndrome in children with acute lymphoblastic leukemia: Clinical characteristics, risk factors, course, and outcome of disease

BACKGROUND

Posterior reversible encephalopathy syndrome (PRES) is a distinct entity with incompletely known predisposing factors. The aim of this study is to describe the incidence, risk factors, clinical course, and outcome of PRES in childhood acute lymphoblastic leukemia (ALL).

PROCEDURE

Patients aged 1.0 to 17.9 years diagnosed with ALL from July 2008 to December 2015 and treated according to the Nordic Society of Pediatric Hematology and Oncology (NOPHO) ALL2008 protocol were included. Patients with PRES were identified in the prospective NOPHO leukemia toxicity registry, and clinical data were collected from the medical records.

RESULTS

The study group included 1378 patients, of whom 52 met the criteria for PRES. The cumulative incidence of PRES at one month was 1.7% (95% CI, 1.1-2.5) and at one year 3.7% (95% CI, 2.9-4.9). Older age (hazard ratios [HR] for each one-year increase in age 1.1; 95% CI, 1.0-1.2, P = 0.001) and T-cell immunophenotype (HR, 2.9; 95% CI, 1.6-5.3, P = 0.0005) were associated with PRES. Central nervous system (CNS) involvement (odds ratios [OR] = 2.8; 95% CI, 1.2-6.5, P = 0.015) was associated with early PRES and high-risk block treatment (HR = 2.63; 95% CI, 1.1-6.4, P = 0.033) with late PRES. At follow-up of the PRES patients, seven patients had epilepsy and seven had neurocognitive difficulties.

CONCLUSION

PRES is a neurotoxicity in the treatment of childhood ALL with both acute and long-term morbidity. Older age, T-cell leukemia, CNS involvement and high-risk block treatment are risk factors for PRES.

The radiological and clinical follow-up of osteonecrosis in cancer patients

BACKGROUND

In patients with cancer, osteonecrosis (ON) lesions can affect multiple sites throughout the skeleton, including the long and short bones and the joints. The aims of this study were to explore the natural course of ON in patients treated for cancer by using radiological classification suitable for multisite ON lesions and to assess correlations between the ON grade and surgical procedures.

MATERIAL AND METHODS

Data were retrieved from hospital databases on 233 ON lesions in 54 patients (aged 2-73 years at cancer diagnosis; mean age: 25 years). ONs were graded according to the Niinimäki classification, based on magnetic resonance images. Medical records were reviewed to identify surgical procedures.

RESULTS

A total of 14 different ON sites were detected; the hip was the most common site (n = 51), followed by the femur (n = 45), tibia (n = 41) and knee (n = 37). Among the 233 ON lesions, 78.1% did not require surgical procedures. The remaining lesions required total joint arthroplasty (TJA; 40/233, 17.2%), core decompression (3.4%) and arthroscopy (1.3%). Most TJAs (33/40, 82.5%) were performed on the hip. ONs of the knee required TJAs only once; grade 3 knee ONs frequently healed (58%, 11/19). None of the diaphyseal or metaphyseal (grade 1-2) ONs of the long bones required surgery, and no fractures of those bones were identified.

CONCLUSIONS

In conclusion, the natural history of ONs varied by the grade and site. Based on our findings, we would not recommend routine radiological follow-ups for grades 1-2 ON lesions that do not affect the joints, because the clinical consequences of those lesions appear to be minimal, although pain relief would be warranted. In contrast, joint deformations (grade 5) require surgery; therefore, intervention studies should focus on grades 3-4 ON lesions.

Comparing osteonecrosis clinical phenotype, timing, and risk factors in children and young adults treated for acute lymphoblastic leukemia

BACKGROUND

Treatment-related osteonecrosis (ON) is a serious complication of treatment of acute lymphoblastic leukemia (ALL).

PROCEDURE

This study included 1,489 patients with ALL, aged 1-45 years, treated according to the Nordic Society of Paediatric Haematology and Oncology ALL2008 protocol, using alternate-week dexamethasone during delayed intensification, with prospective registration of symptomatic ON. We aimed at comparing risk factors, timing, and clinical characteristics of ON in children and young adults.

RESULTS

ON was diagnosed in 67 patients, yielding a 5-year cumulative incidence of 6.3%, but 28% in female adolescents. Median age at ALL diagnosis was 12.1 years and 14.9 years for females and males, respectively. At ON diagnosis, 59 patients had bone pain (91%) and 30 (46%) had multiple-joint involvement. The median interval between ALL and ON diagnosis was significantly shorter in children aged 1.0-9.9 years (0.7 years [range: 0.2-2.1]) compared with adolescents (1.8 years [range: 0.3-3.7, P < 0.001]) and adults (2.1 years [range: 0.4-5.3, P = 0.001]). Female sex was a risk factor in adolescent patients (hazard ratio [HR] = 2.1, 95% confidence interval [CI]: 1.1-4.2) but not in children aged 1.1-9.9 years (HR = 2.4, 95% CI: 0.9-6.2, P = 0.08) or adults aged 19-45 years (HR = 1.1, 95% CI: 0.3-4.0). Age above 10 years at ALL diagnosis (odds ratio [OR] = 3.7, P = 0.026) and multiple joints affected at ON diagnosis (OR = 3.4, P = 0.027) were risk factors for developing severe ON.

CONCLUSION

We provide a detailed phenotype of patients with ALL with symptomatic ON, including description of risk factors and timing of ON across age groups. This awareness is essential in exploring measures to prevent development of ON.

Altered MicroRNA Profile in Osteoporosis Caused by Impaired WNT Signaling

CONTEXT

WNT signaling is fundamental to bone health, and its aberrant activation leads to skeletal pathologies. The heterozygous missense mutation p.C218G in WNT1, a key WNT pathway ligand, leads to severe early-onset and progressive osteoporosis with multiple peripheral and spinal fractures. Despite the severe skeletal manifestations, conventional bone turnover markers are normal in mutation-positive patients.

OBJECTIVE

This study sought to explore the circulating microRNA (miRNA) pattern in patients with impaired WNT signaling.

DESIGN AND SETTING

A cross-sectional cohort study at a university hospital.

PARTICIPANTS

Altogether, 12 mutation-positive (MP) subjects (median age, 39 years; range, 11 to 76 years) and 12 mutation-negative (MN) subjects (35 years; range, 9 to 59 years) from two Finnish families with WNT1 osteoporosis due to the heterozygous p.C218G WNT1 mutation.

METHODS AND MAIN OUTCOME MEASURE

Serum samples were screened for 192 miRNAs using quantitative polymerase chain reaction. Findings were compared between WNT1 MP and MN subjects.

RESULTS

The pattern of circulating miRNAs was significantly different in the MP subjects compared with the MN subjects, with two upregulated (miR-18a-3p and miR-223-3p) and six downregulated miRNAs (miR-22-3p, miR-31-5p, miR-34a-5p, miR-143-5p, miR-423-5p, and miR-423-3p). Three of these (miR-22-3p, miR-34a-5p, and miR-31-5p) are known inhibitors of WNT signaling: miR-22-3p and miR-34a-5p target WNT1 messenger RNA, and miR-31-5p is predicted to bind to WNT1 3'UTR.

CONCLUSIONS

The circulating miRNA pattern reflects WNT1 mutation status. The findings suggest that the WNT1 mutation disrupts feedback regulation between these miRNAs and WNT1, providing insights into the pathogenesis of WNT-related bone disorders. These miRNAs may have potential in the diagnosis and treatment of osteoporosis.

Defective WNT signaling associates with bone marrow fibrosis-a cross-sectional cohort study in a family with WNT1 osteoporosis

This study explores bone marrow function in patients with defective WNT1 signaling. Bone marrow samples showed increased reticulin and altered granulopoiesis while overall hematopoiesis was normal. Findings did not associate with severity of osteoporosis. These observations provide new insight into the role of WNT signaling in bone marrow homeostasis.

INTRODUCTION

WNT signaling regulates bone homeostasis and survival and self-renewal of hematopoietic stem cells. Aberrant activation may lead to osteoporosis and bone marrow pathology. We aimed to explore bone marrow findings in a large family with early-onset osteoporosis due to a heterozygous WNT1 mutation.

METHODS

We analyzed peripheral blood samples, and bone marrow aspirates and biopsies from 10 subjects with WNT1 mutation p.C218G. One subject was previously diagnosed with idiopathic myelofibrosis and others had no previously diagnosed hematologic disorders. The findings were correlated with the skeletal phenotype, as evaluated by number of peripheral and spinal fractures and bone mineral density.

RESULTS

Peripheral blood samples showed no abnormalities in cell counts, morphology or distributions but mild increase in platelet count. Bone marrow aspirates (from 8/10 subjects) showed mild decrease in bone marrow iron storages in 6 and variation in cell distributions in 5 subjects. Bone marrow biopsies (from 6/10 subjects) showed increased bone marrow reticulin (grade MF-2 in the myelofibrosis subject and grade MF-1 in 4 others), and an increase in overall, and a shift towards early-phase, granulopoiesis. The bone marrow findings did not associate with the severity of skeletal phenotype.

CONCLUSIONS

Defective WNT signaling associates with a mild increase in bone marrow reticulin and may predispose to myelofibrosis, while overall hematopoiesis and peripheral blood values are unaltered in individuals with a WNT1 mutation. In this family with WNT1 osteoporosis, bone marrow findings were not related to the severity of osteoporosis.

Novel non-neutral mitochondrial DNA mutations found in childhood acute lymphoblastic leukemia

Mitochondria produce adenosine triphosphate (ATP) for energy requirements via the mitochondrial oxidative phosphorylation (OXPHOS) system. One of the hallmarks of cancer is the energy shift toward glycolysis. Low OXPHOS activity and increased glycolysis are associated with aggressive types of cancer. Mitochondria have their own genome (mitochondrial DNA [mtDNA]) encoding for 13 essential subunits of the OXPHOS enzyme complexes. We studied mtDNA in childhood acute lymphoblastic leukemia (ALL) to detect potential pathogenic mutations in OXPHOS complexes. The whole mtDNA from blood and bone marrow samples at diagnosis and follow-up from 36 ALL patients were analyzed. Novel or previously described pathogenic mtDNA mutations were identified in 8 out of 36 patients. Six out of these 8 patients had died from ALL. Five out of 36 patients had an identified poor prognosis genetic marker, and 4 of these patients had mtDNA mutations. Missense or nonsense mtDNA mutations were detected in the genes encoding subunits of OXPHOS complexes, as follows: MT-ND1, MT-ND2, MT-ND4L and MT-ND6 of complex I; MT-CO3 of complex IV; and MT-ATP6 and MT-ATP8 of complex V. We discovered mtDNA mutations in childhood ALL supporting the hypothesis that non-neutral variants in mtDNA affecting the OXPHOS function may be related to leukemic clones.

Bone marrow failure syndrome caused by homozygous frameshift mutation in the ERCC6L2 gene

Inherited bone marrow failure syndromes (IBMFS) are group of disorders that lead to inadequate production of blood cells. Mutations in genes involved in telomere maintenance, DNA repair, and the cell cycle cause IBMFS. ERCC6L2 gene mutations have been associated with bone marrow failure that includes developmental delay and microcephaly. We report 2 cases of bone marrow failure with no extra-hematopoietic manifestations in patients from unrelated families with a homozygous truncating mutation in ERCC6L2. Bone marrow failure without developmental delay or microcephaly with ERCC6L2 mutation has not been previously described.

Consensus definitions of 14 severe acute toxic effects for childhood lymphoblastic leukaemia treatment: a Delphi consensus

Although there are high survival rates for children with acute lymphoblastic leukaemia, their outcome is often counterbalanced by the burden of toxic effects. This is because reported frequencies vary widely across studies, partly because of diverse definitions of toxic effects. Using the Delphi method, 15 international childhood acute lymphoblastic leukaemia study groups assessed acute lymphoblastic leukaemia protocols to address toxic effects that were to be considered by the Ponte di Legno working group. 14 acute toxic effects (hypersensitivity to asparaginase, hyperlipidaemia, osteonecrosis, asparaginase-associated pancreatitis, arterial hypertension, posterior reversible encephalopathy syndrome, seizures, depressed level of consciousness, methotrexate-related stroke-like syndrome, peripheral neuropathy, high-dose methotrexate-related nephrotoxicity, sinusoidal obstructive syndrome, thromboembolism, and Pneumocystis jirovecii pneumonia) that are serious but too rare to be addressed comprehensively within any single group, or are deemed to need consensus definitions for reliable incidence comparisons, were selected for assessment. Our results showed that none of the protocols addressed all 14 toxic effects, that no two protocols shared identical definitions of all toxic effects, and that no toxic effect definition was shared by all protocols. Using the Delphi method over three face-to-face plenary meetings, consensus definitions were obtained for all 14 toxic effects. In the overall assessment of outcome of acute lymphoblastic leukaemia treatment, these expert opinion-based definitions will allow reliable comparisons of frequencies and severities of acute toxic effects across treatment protocols, and facilitate international research on cause, guidelines for treatment adaptation, preventive strategies, and development of consensus algorithms for reporting on acute lymphoblastic leukaemia treatment.

Role of neuroimaging in children with acute lymphoblastic leukemia and central nervous system involvement at diagnosis

BACKGROUND

Each year approximately 200 children and adolescents are diagnosed with acute lymphoblastic leukemia (ALL) in the five Nordic countries, and 3% of these have central nervous system (CNS) involvement confirmed by leukemic cells in the cerebrospinal fluid (CSF) or neurological symptoms. We sought to determine the significance of neuraxis imaging in such patients.

PROCEDURE

Magnetic resonance images of children aged 1-17.9 with CNS leukemia at diagnosis of ALL were centrally reviewed and clinical data were retrieved from the medical records and the Nordic leukemia registry. Patients were diagnosed in the period 2000-2012 in Sweden, Finland, or Denmark.

RESULTS

The cohort comprised 1,877 patients, and 66 (3.5%) had CNS involvement. Forty-five percent (30/66) had CNS related symptoms. Symptoms included vomiting, facial palsy, headache, visual symptoms, and impaired hearing. CNS imaging was performed in 32 of 66 children (48%), and confirmed CNS involvement in 6 of 21 patients with symptoms (29%) and 5 of 11 (45%) without (P = 0.44). There was no difference in the overall survival between CNS-positive patients with and without signs of leukemic involvement by imaging (P = 0.53).

CONCLUSIONS

Radiological imaging of asymptomatic children with CNS leukemia at diagnosis lacks clinical importance, but may be useful in patients with cranial nerve symptoms and negative CSF, as well as for follow-up. Imaging of symptomatic patients is warranted in order to exclude other causes underlying the symptoms.

Leukemic blasts are present at low levels in spinal fluid in one-third of childhood acute lymphoblastic leukemia cases

BACKGROUND

Central nervous system (CNS) involvement is associated with relapse in childhood acute lymphoblastic leukemia (ALL) and is a diagnostic challenge.

PROCEDURE

In a Nordic/Baltic prospective study, we assessed centralized flow cytometry (FCM) of locally fixed cerebrospinal fluid (CSF) samples versus local conventional cytospin-based cytology (CC) for detecting leukemic cells and evaluating kinetics of elimination of leukemic cells in CSF.

RESULTS

Among 300 patients with newly diagnosed ALL, 87 (29%) had CSF involvement by FCM, while CC was positive in 30 (10%) of 299 patients with available CC data (P < 0.001). Patients with FCM+/CC+ had higher CSF leukemic blast counts compared to patients positive by FCM only (medians: 0.10 vs. 0.017 leukemic blasts/μl, P = 0.006). Patients positive by FCM had higher white blood cell counts in peripheral blood than patients negative by FCM (medians: 45 × 10(9) /l vs. 10 × 10(9) /l, P < 0.001), were younger (medians: 3 years vs. 4 years, P = 0.03), and more frequently had T-cell ALL (18/87 vs. 16/213, P = 0.001). At treatment day 15, five of 52 patients (10%) who had CSF positive by FCM at diagnosis remained so despite at least two doses of weekly intrathecal chemotherapy.

CONCLUSIONS

Longer follow-up is needed to clarify whether FCM positivity has prognostic significance and is an indicator for intensified CNS-directed therapy.

The classification of osteonecrosis in patients with cancer: validation of a new radiological classification system

AIM

To validate a new, non-joint-specific radiological classification system that is suitable regardless of the site of the osteonecrosis (ON) in patients with cancer.

MATERIAL AND METHODS

Critical deficiencies in the existing ON classification systems were identified and a new, non-joint-specific radiological classification system was developed. Seventy-two magnetic resonance imaging (MRI) images of patients with cancer and ON lesions were graded, and the validation of the new system was performed by assessing inter- and intra-observer reliability.

RESULTS

Intra-observer reliability of ON grading was good or very good, with kappa values of 0.79-0.86. Interobserver agreement was lower but still good, with kappa values of 0.62-0.77. Ninety-eight percent of all intra- or interobserver differences were within one grade. Interobserver reliability of assessing the location of ON was very good, with kappa values of 0.93-0.98.

CONCLUSION

All the available radiological ON classification systems are joint specific. This limitation has spurred the development of multiple systems, which has led to the insufficient use of classifications in ON studies among patients with cancer. The introduced radiological classification system overcomes the problem of joint-specificity, was found to be reliable, and can be used to classify all ON lesions regardless of the affected site.

The diagnosis and classification of osteonecrosis in patients with childhood leukemia

Osteonecrosis is a well-recognized complication in patients with childhood leukemia. Its clinical relevance is highly dependent on the size and location of the lesion. Therefore, the diagnosis, description of the affected site and the classification of the disease, must be precise. We conducted an extensive literature review to assess the quality of studies reporting the incidence of osteonecrosis in patients with childhood leukemia. Of the 31 included studies, one-third (32% [n = 10]) did not describe the diagnostic method that was used to assess osteonecrosis. In almost two-third (61% [n = 19]) of the studies, the osteonecrosis classification system was not used. We conclude that the quality of most published studies on the incidence of osteonecrosis in patients with childhood leukemia is relatively poor because many studies did not describe the radiological method used to diagnose osteonecrosis and/or did not use a validated osteonecrosis classification system. To compare the incidence of osteonecrosis, and to assess the severity and clinical consequences of osteonecrosis in patients with childhood leukemia, there is a need for a robust and widely recognized classification system to grade all cases of osteonecrosis despite the site of lesion. Pediatr Blood Cancer 2015;62:198-203. © 2014 Wiley Periodicals, Inc.

Osteonecrosis requiring total joint arthroplasty is a rare sequel in children and young adults treated for solid tumors

BACKGROUND

Osteonecrosis (ON) is a potential sequel in patients treated for malignancies. The goal of this population-based register study was to determine the incidence of ON requiring total joint arthroplasty (TJA) in patients treated for solid tumors in childhood, adolescence, or early adulthood.

MATERIAL AND METHODS

Patients diagnosed with a solid tumor before the age of 31 years were identified from the Finnish and Danish Cancer Registries. Patients with non-melanoma skin cancers and bone and connective tissue cancers were excluded. The data were combined with data from the National Hospital Discharge Registers and the Finnish Arthroplasty Registry. Data on the orthopedic procedures performed and the diagnosis codes given before the age of 40 years were retrieved.

RESULTS

Twenty-five of 18 542 (0.13%) patients had undergone TJA. The overall 20-year cumulative incidence of ON requiring TJA was 1% in patients treated for kidney cancer, followed by 0.5% in patients with breast cancer and 0.2% in patients with testicular cancer.

CONCLUSION

Severe ON requiring TJA is a rare sequel in children and young adults treated for solid tumors. It was observed most commonly in patients treated for renal, breast, or testicular cancer.

Incidence of Severe Osteonecrosis Requiring Total Joint Arthroplasty in Children and Young Adults Treated for Leukemia or Lymphoma: A Nationwide, Register-Based Study in Finland and Denmark

Purpose: The population-based incidence of severe osteonecrosis (ON) necessitating total joint arthroplasty (TJA) in patients with hematological cancer is unknown. This study assessed the incidence of ON requiring primary TJA in children and young adults treated for leukemia or lymphoma. Methods: Patients diagnosed with leukemia or lymphoma before 31 years of age were identified from the Finnish and Danish Cancer Registries. These data were combined with those from the National Hospital Discharge and the Finnish Arthroplasty Registers. Data on the orthopedic procedures performed and the appropriate diagnosis codes given before the age of 40 were also retrieved. Results: The estimated cumulative incidence of TJA was 4.5% at 20 years for patients treated for chronic myeloid leukemia, followed by 2.1% for patients treated for acute myeloid leukemia. It was considerably lower in patients with acute lymphoblastic leukemia (ALL; 0.4%). Multivariate analysis revealed that allogeneic stem cell transplantation (allo-SCT) increased the risk of TJA (hazard ratio [HR]=9.4; 95% CI: 5.3-16.9). The risk of TJA was higher in patients diagnosed with cancer at 10-19 and 20-30 years of age than in those diagnosed before the age of 10 (HR=24; 95% CI: 3.1-176 and HR=26; 95% CI: 3.6-192 respectively). Conclusion: The incidence of ON requiring TJA was highest among patients with myeloid leukemias and lowest in patients treated for ALL. Allo-SCT and age ≥10 years at diagnosis were the most important risk factors for ON requiring TJA in hematological malignancies.