Hodgkin Lymphoma Involving the Extra-Axial CNS: An AHOD1331, PHL-C1 and PHL-C2 Report From the COG and EuroNet-PHL.

Hodgkin lymphoma (HL) involving the central nervous system (CNS) is exceedingly rare. Information regarding the presentation, management, treatment and outcome of patients with CNS HL is limited to case reports or small series. We describe 45 pediatric patients with 55 extra-axial CNS lesions at diagnosis with HL from a cohort of 4995 patients enrolled on Children's Oncology Group AHOD1331 and the European Network for Pediatric Hodgkin lymphoma (EuroNet-PHL) C1 and C2 trials (NCT02166463, NCT00433459 and NCT02684708, clinicaltrials.gov), with an overall incidence of 0.9%. 82.2% of patients had a single CNS lesion in the thoracic, lumbar or sacral spine. In the evaluated cohort, HL did not occur within the CNS parenchyma. Lesions extended into the extra-axial CNS space from adjacent soft tissue or bone and never directly infiltrated through the dura into the brain or spinal cord. Patients with CNS involvement had a 2-fold greater incidence of extranodal lesions (E-lesions) than previously reported cohorts without CNS involvement. 89.1% of CNS lesions demonstrated a complete metabolic response and >75% decrease in volume after two cycles of chemotherapy. Thirteen CNS lesions (23.6%) received irradiation, none were sites of disease relapse. Relapse occurred at the site of two lesions involving the CNS, both of which had an adequate interim response to chemotherapy. In summary, we present the largest reported cohort of systemic HL involving the CNS at diagnosis, demonstrating that these lesions originate from surrounding tissues, extend into the extra-axial CNS space, and respond similarly to other nodal and extranodal disease.

Longitudinal Health-Related Quality of Life Among Patients With High-Risk Pediatric Hodgkin Lymphoma Treated on the Children's Oncology Group AHOD 1331 Study.

PURPOSE: There have been no previous longitudinal assessments of health-related quality of life (HRQoL) during treatment for pediatric Hodgkin lymphoma (HL). The addition of brentuximab vedotin (BV) to a multidrug chemotherapy backbone demonstrated superior efficacy to standard chemotherapy for patients with pediatric high-risk HL in the AHOD 1331 trial. However, the impact on HRQoL is unknown. PATIENTS AND METHODS: After treatment random assignment, 268 participants older than 11 years were enrolled in a prespecified, longitudinal, patient-reported outcomes substudy. HRQoL was assessed using the seven-item Child Health Ratings Inventories (CHRIs)-Global scale before treatment (T1) and at cycle 2 (T2), cycle 5 (T3), and end of treatment (T4). A clinically meaningful increase in HRQoL was considered 7 points on the CHRIs-Global. Multivariable linear regression estimated associations between demographic/clinical variables and HRQoL at T1. Linear mixed models estimated changes in HRQoL across the treatment arm. RESULTS: Participant characteristics were balanced by treatment arm. Ninety-three percent of participants completed the CHRIs at T1, 92% at T2, 89% at T3, and 77% at T4. At T1, female sex and fever (P < .05) were each associated with worse HRQoL. By T2, participants in the BV arm experienced a statistically and clinically significant improvement in HRQoL (ß = 7.3 [95% CI, 3.2 to 11.4]; P ≤ .001), which was greater than the change in the standard arm (difference in change ß = 5.1 [95% CI, -0.2 to 10.3]; P = .057). The standard arm did not experience a statistically or clinically significant increase in HRQoL until T4 (ß = 9.3 [95% CI, 4.7 to 11.5]; P < .001). CONCLUSION: These data demonstrate successful collection of serial HRQoL from youth with high-risk pediatric HL and improvement in HRQoL over the course of initial therapy, sooner and to a greater extent in the group receiving the novel agent BV.

Toxicity profile of high-dose methotrexate in young children with central nervous system tumors.

High-dose methotrexate (HD-MTX) is used in the treatment of children with central nervous system (CNS) tumors; however, toxicity information is limited. We characterized toxicities following 102 administrations of HD-MTX (4.6-13.5 g/m2) infused over 4 or 24 h in 38 children with a CNS tumor before 6 years of age (2010-2020). Delayed clearance of methotrexate occurred following 24% of infusions. Common Terminology Criteria for Adverse Events v5 grade 2-3 mucositis was observed in 47% of individuals, Grade 4 neutropenia in 76%, and grade 3-4 thrombocytopenia in 58%. No neurotoxicity was observed. HD-MTX can be safely used with supportive care and monitoring.

HLH and Recurrent EBV Lymphoma as the presenting manifestation of MAGT1 Deficiency: A Systematic Review of the Expanding Disease Spectrum.

Magnesium transporter 1 (MAGT1) gene loss-of-function variants lead to X-linked MAGT1 deficiency with increased susceptibility to EBV infection and N-glycosylation defect (XMEN), a condition with a variety of clinical and immunological effects. In addition, MAGT1 deficiency has been classified as a congenital disorder of glycosylation (CDG) due to its unique role in glycosylation of multiple substrates including NKG2D, necessary for viral protection. Due to the predisposition for EBV, this etiology has been linked with hemophagocytic lymphohistiocytosis (HLH), however only limited literature exists. Here we present a complex case with HLH and EBV-driven classic Hodgkin lymphoma (cHL) as the presenting manifestation of underlying immune defect. However, the patient's underlying immunodeficiency was not identified until his second recurrence of Hodgkin disease, recurrent episodes of Herpes Zoster, and after he had undergone autologous hematopoietic stem cell transplant (HSCT) for refractory Hodgkin lymphoma. This rare presentation of HLH and recurrent lymphomas without some of the classical immune deficiency manifestations of MAGT1 deficiency led us to review the literature for similar presentations and to report the evolving spectrum of disease in published literature. Our systematic review showcased that MAGT1 predisposes to multiple viruses (including EBV) and adds risk of viral-driven neoplasia. The roles of MAGT1 in the immune system and glycosylation were highlighted through the multiple organ dysfunction showcased by the previously validated Immune Deficiency and Dysregulation Activity (IDDA2.1) score and CDG-specific Nijmegen Pediatric CDG Rating Scale (NPCRS) score for the patient cohort in the systematic review.

Pediatric and Adolescent Hodgkin Lymphoma: Paving the Way for Standards of Care and Shared Decision Making.

Hodgkin lymphoma (HL) is a treatable cancer with an incidence peak in adolescent and young adult years. Treatment strategies have been developed to balance the intensity of therapy needed to maintain disease-free survival while simultaneously preserving overall survival. Risk-based, response-adapted frontline therapy has long used a combination of chemotherapy and radiotherapy (RT). Successive clinical trials over the past three decades have safely reduced cumulative alkylator, anthracycline, and RT exposures for many patients. The advent of checkpoint inhibitors and the CD30-targeted antibody drug conjugate, brentuximab vedotin, has provided new options for de-escalation of conventional therapies associated with late effects in survivors treated at a young age. The ability to evaluate novel agents has been accelerated in collaborative trials inclusive of children and adolescents within the US National Clinical Trials Network and between the Children's Oncology Group and the EuroNet Pediatric Hodgkin Lymphoma Consortium. With numerous treatment options, patients with HL and their clinicians have an opportunity for shared decision making from diagnosis, through cancer treatment, and into survivorship. Given excellent survival outcomes, decisions about treatment in classic HL should be collaborative and attention to long-term survivorship needs should remain a high priority. Patient-reported outcomes remain an important tool to aid clinicians working with survivors to optimize health status and related quality of life for decades after HL therapy.

A systematic literature review of clinical evidence and treatment burden in newly diagnosed high-risk pediatric patients with classical Hodgkin lymphoma.

This systematic literature review evaluated frontline treatment burden in pediatric and adolescent/young adult (AYA) patients with high-risk classical Hodgkin lymphoma (cHL) among studies originating from the United States. Data were extracted from 32 publications (screened: total, n = 3115; full-text, n = 98) representing 12 studies (randomized controlled trials [RCTs], n = 2; non-comparative, non-randomized, n = 7; observational, n = 3). High-risk disease definitions varied across studies. Five-year event-free survival (EFS)/progression-free survival (PFS) was 86%-100% and 79%-94%, and complete response rates were 35%-100% and 5%-64% for brentuximab vedotin (BV)-containing and chemotherapy-alone regimens, respectively. In identified RCTs, BV-containing compared with chemotherapy-alone regimens demonstrated significantly longer 3-year EFS/5-year PFS. Hematological and peripheral neuropathy were the most commonly reported adverse events of interest, although safety data were inconsistently reported. Few studies evaluated humanistic and no studies evaluated economic burden. Results from studies with the highest quality of evidence indicate an EFS/PFS benefit for frontline BV-containing versus chemotherapy-alone regimens for pediatric/AYA patients with high-risk cHL.

Exposure-Response and Subgroup Analyses to Support Body Weight-Based Dosing of Brentuximab Vedotin in Children and Young Adults with Newly Diagnosed High-risk Classical Hodgkin Lymphoma.

PURPOSE: The purpose of the study was to evaluate the relationships between brentuximab vedotin (BV) pharmacokinetics, age, and body weight (BW) with efficacy and safety in pediatric and young adult patients with previously untreated, high-risk classical Hodgkin lymphoma in the phase III AHOD1331 study. EXPERIMENTAL DESIGN: Overall, 296 patients (age 2-21 years) in the overall population were randomized to and received BV + chemotherapy; the pharmacokinetic subpopulation comprised 24 patients (age <13 years). Age- and/or BW-based (pharmacokinetic surrogates) subgroup analyses of efficacy and safety were conducted for the overall population. Exposure-response analyses were limited to the pharmacokinetic subpopulation. RESULTS: There were no visible trends in disease characteristics across pediatric age subgroups, whereas BW increased with age. Observed antibody-drug conjugate exposures in patients ages <12 years were lower than those in adults administered BV 1.8 mg/kg every 3 weeks, as exposure increased with BW. Nevertheless, no detrimental impact on event-free survival was seen in younger subgroups: 3-year event-free survival rates were 96.2% (2-<12 years) and 92.0% (12-<18 years), with no events observed in those ages <6 years. Neither early response nor lack of need for radiation therapy was associated with high pharmacokinetic exposure. No evidence of exposure-driven grade ≥2 or ≥3 peripheral neuropathy or grade ≥3 neutropenia was seen in exposure-safety and BW-based subgroup analyses; the incidence of these safety events was comparable across pediatric age subgroups, despite lower exposure in younger children. CONCLUSIONS: No further adjustments based on age or BW are required for the BV dosage (1.8 mg/kg every 3 weeks) approved in children.

Automatic Quantification of Serial PET/CT Images for Pediatric Hodgkin Lymphoma Patients Using a Longitudinally-Aware Segmentation Network.

Purpose: Automatic quantification of longitudinal changes in PET scans for lymphoma patients has proven challenging, as residual disease in interim-therapy scans is often subtle and difficult to detect. Our goal was to develop a longitudinally-aware segmentation network (LAS-Net) that can quantify serial PET/CT images for pediatric Hodgkin lymphoma patients. Materials and Methods: This retrospective study included baseline (PET1) and interim (PET2) PET/CT images from 297 patients enrolled in two Children's Oncology Group clinical trials (AHOD1331 and AHOD0831). LAS-Net incorporates longitudinal cross-attention, allowing relevant features from PET1 to inform the analysis of PET2. Model performance was evaluated using Dice coefficients for PET1 and detection F1 scores for PET2. Additionally, we extracted and compared quantitative PET metrics, including metabolic tumor volume (MTV) and total lesion glycolysis (TLG) in PET1, as well as qPET and ΔSUVmax in PET2, against physician measurements. We quantified their agreement using Spearman's ρ correlations and employed bootstrap resampling for statistical analysis. Results: LAS-Net detected residual lymphoma in PET2 with an F1 score of 0.606 (precision/recall: 0.615/0.600), outperforming all comparator methods (P<0.01). For baseline segmentation, LAS-Net achieved a mean Dice score of 0.772. In PET quantification, LAS-Net's measurements of qPET, ΔSUVmax, MTV and TLG were strongly correlated with physician measurements, with Spearman's ρ of 0.78, 0.80, 0.93 and 0.96, respectively. The performance remained high, with a slight decrease, in an external testing cohort. Conclusion: LAS-Net achieved high performance in quantifying PET metrics across serial scans, highlighting the value of longitudinal awareness in evaluating multi-time-point imaging datasets.

Personalized Impression Generation for PET Reports Using Large Language Models.

Large language models (LLMs) have shown promise in accelerating radiology reporting by summarizing clinical findings into impressions. However, automatic impression generation for whole-body PET reports presents unique challenges and has received little attention. Our study aimed to evaluate whether LLMs can create clinically useful impressions for PET reporting. To this end, we fine-tuned twelve open-source language models on a corpus of 37,370 retrospective PET reports collected from our institution. All models were trained using the teacher-forcing algorithm, with the report findings and patient information as input and the original clinical impressions as reference. An extra input token encoded the reading physician's identity, allowing models to learn physician-specific reporting styles. To compare the performances of different models, we computed various automatic evaluation metrics and benchmarked them against physician preferences, ultimately selecting PEGASUS as the top LLM. To evaluate its clinical utility, three nuclear medicine physicians assessed the PEGASUS-generated impressions and original clinical impressions across 6 quality dimensions (3-point scales) and an overall utility score (5-point scale). Each physician reviewed 12 of their own reports and 12 reports from other physicians. When physicians assessed LLM impressions generated in their own style, 89% were considered clinically acceptable, with a mean utility score of 4.08/5. On average, physicians rated these personalized impressions as comparable in overall utility to the impressions dictated by other physicians (4.03, P = 0.41). In summary, our study demonstrated that personalized impressions generated by PEGASUS were clinically useful in most cases, highlighting its potential to expedite PET reporting by automatically drafting impressions.

Accelerating pediatric Hodgkin lymphoma research: the Hodgkin Lymphoma Data Collaboration (NODAL).

Data commons have proven to be an indispensable avenue for advancing pediatric cancer research by serving as unified information technology platforms that, when coupled with data standards, facilitate data sharing. The Pediatric Cancer Data Commons, the flagship project of Data for the Common Good (D4CG), collaborates with disease-based consortia to facilitate development of clinical data standards, harmonization and pooling of clinical data from disparate sources, establishment of governance structure, and sharing of clinical data. In the interest of international collaboration, researchers developed the Hodgkin Lymphoma Data Collaboration and forged a relationship with the Pediatric Cancer Data Commons to establish a data commons for pediatric Hodgkin lymphoma. Herein, we describe the progress made in the formation of Hodgkin Lymphoma Data Collaboration and foundational goals to advance pediatric Hodgkin lymphoma research.

Late Cardiac Toxic Effects Associated With Treatment Protocols for Hodgkin Lymphoma in Children.

Importance: Contemporary North American trials for children with Hodgkin lymphoma (HL) have decreased radiation therapy (RT) use and increased pharmacologic cardioprotection but also increased the cumulative doxorubicin dose, making overall treatment consequences for late cardiac toxic effects uncertain. Objective: To estimate the risk of cardiac toxic effects associated with treatments used in modern pediatric HL clinical trials. Design, Setting, and Participants: For this cohort study, Fine and Gray models were fitted using survivors in the Childhood Cancer Survivor Study who were diagnosed with HL between January 1, 1970, and December 31, 1999, and were followed for a median of 23.5 (range, 5.0-46.3) years. These models were applied to the exposures in the study population to estimate the 30-year cumulative incidence of cardiac disease. The study population comprised patients with intermediate-risk or high-risk HL treated in 4 consecutive Children's Oncology Group clinical trials from September 2002 to October 2022: AHOD0031, AHOD0831, AHOD1331, and S1826. Data analysis was performed from April 2020 to February 2023. Exposures: All patients received chemotherapy including doxorubicin, and some patients received mediastinal RT, dexrazoxane, or mediastinal RT and dexrazoxane. Main Outcomes and Measures: Estimated 30-year cumulative incidence of grade 3 to 5 cardiac disease. Results: The study cohort comprised 2563 patients, with a median age at diagnosis of 15 (range, 1-22) years. More than half of the patients were male (1357 [52.9%]). All 2563 patients received doxorubicin, 1362 patients (53.1%) received mediastinal RT, and 307 patients (12.0%) received dexrazoxane. Radiation therapy use and the median mean heart dose among patients receiving RT decreased, whereas the planned cumulative dose of doxorubicin and use of dexrazoxane cardioprotection increased. For patients treated at age 15 years, the estimated 30-year cumulative incidence of severe or fatal cardiac disease was 9.6% (95% CI, 4.2%-16.4%) in the AHOD0031 standard treatment group (enrolled 2002-2009), 8.6% (95% CI, 3.8%-14.9%) in the AHOD0831 trial (enrolled 2009-2012), 8.2% (95% CI, 3.6%-14.3%) in the AHOD1331 trial (enrolled 2015-2019), and 6.2% (95% CI, 2.7%-10.9%) in the S1826 trial (enrolled 2019-2022), whereas the expected rate in an untreated population was 5.0% (95% CI, 2.1%-9.3%). Despite the estimated reduction in late cardiac morbidity, the frequency of recommended echocardiographic screening among survivors will increase based on current guidelines. Conclusions and Relevance: In this cohort study of sequential HL trials, reductions in the proportion of children receiving mediastinal RT and increases in dexrazoxane use were estimated to offset the increased doxorubicin dose and produce a net reduction in late cardiac disease. Further studies on dexrazoxane are warranted to confirm whether its role in reducing cardiac toxic effects is maintained long term. These findings suggest that survivorship follow-up guidelines should be refined to align with the risks associated with treatment.

Distinct Hodgkin lymphoma subtypes defined by noninvasive genomic profiling.

The scarcity of malignant Hodgkin and Reed-Sternberg cells hampers tissue-based comprehensive genomic profiling of classic Hodgkin lymphoma (cHL). By contrast, liquid biopsies show promise for molecular profiling of cHL due to relatively high circulating tumour DNA (ctDNA) levels1-4. Here we show that the plasma representation of mutations exceeds the bulk tumour representation in most cases, making cHL particularly amenable to noninvasive profiling. Leveraging single-cell transcriptional profiles of cHL tumours, we demonstrate Hodgkin and Reed-Sternberg ctDNA shedding to be shaped by DNASE1L3, whose increased tumour microenvironment-derived expression drives high ctDNA concentrations. Using this insight, we comprehensively profile 366 patients, revealing two distinct cHL genomic subtypes with characteristic clinical and prognostic correlates, as well as distinct transcriptional and immunological profiles. Furthermore, we identify a novel class of truncating IL4R mutations that are dependent on IL-13 signalling and therapeutically targetable with IL-4Rα-blocking antibodies. Finally, using PhasED-seq5, we demonstrate the clinical value of pretreatment and on-treatment ctDNA levels for longitudinally refining cHL risk prediction and for detection of radiographically occult minimal residual disease. Collectively, these results support the utility of noninvasive strategies for genotyping and dynamic monitoring of cHL, as well as capturing molecularly distinct subtypes with diagnostic, prognostic and therapeutic potential.

Missing the mark? Exploratory analysis of the 10-year-old cutoff as an independent marker of high-risk disease in pediatric B-ALL.

This single-center, retrospective study evaluated age as a risk factor for relapsed/refractory disease and/or death in 153 children with B-cell acute lymphoblastic leukemia. The study sample included children near the 10-year age cutoff for high-risk disease (6.0-13.9 years at diagnosis) and without other high-risk features (high white cell count, unfavorable cytogenetics). Children 10.0-13.9 years treated per high-risk protocols did not have inferior outcomes compared with children aged 6.0-9.9 years initiating treatment per standard-risk protocols. The study indicates that, in the era of cytogenetics, an age threshold of 10 years might not be an independent prognostic marker. Multicenter analyses are needed.

Utilization of cardiac tests in anthracycline-treated cancer survivors differs between young adults and children: A claims-based analysis.

BACKGROUND: The Children's Oncology Group Guidelines recommend a cardiacechocardiogram, or comparable functional imaging, following therapy completion in survivors of childhood/adolescent cancers exposed to anthracyclines. METHODS: Using the 2009-2019 Merative™ MarketScan® Commercial Database, we examined real-world utilization of cardiac testing among 1609 anthracycline-treated survivors of childhood/adolescent cancers. RESULTS: The cumulative incidence of receiving an initial cardiac test by 5.25 years from the index date (six months after end-of-therapy) was 62.3% (95% CI = 57.5%-66.7%), with median time to initial test being 2.7 years (95% CI = 2.5%-3.1%). Young adults (18-28 years) were less likely than children (≤17 years) to receive cardiac testing (hazard ratio [HR] = 0.42, 95% CI = 0.3%-0.49%). More likely to receive cardiac testing were survivors receiving hematopoietic stem cell transplantation versus chemotherapy only (HR = 2.23, 95% CI = 1.63%-3.03%), and survivors with bone or soft tissue versus hematologic cancer (HR = 1.64, 95% CI = 1.30%-2.07%). CONCLUSIONS: Nearly 40% of anthracycline-treated survivors of childhood/adolescent cancers had not received cardiac testing within 5.25 years post-index date, with young adults least likely to receive a test.

Performance of the FACT-GOG-Ntx to assess chemotherapy-induced peripheral neuropathy (CIPN) in pediatric high risk Hodgkin lymphoma: report from the Children's Oncology Group AHOD 1331 study.

BACKGROUND: Chemotherapy-induced peripheral neuropathy (CIPN) is an under-recognized complication of several chemotherapy agents used as part of curative-intent therapy for Hodgkin Lymphoma (HL). In the absence of validated self- or proxy-report measures for children and adolescents, CIPN reporting has relied on clinician rating, with grading scales often restricted to severe manifestations. In a proof-of-concept study, we assessed the feasibility and psychometric performance of the Functional Assessment of Cancer Therapy-Gynecologic Oncology Group-Neurotoxicity (FACT-GOG-Ntx), a unidimensional CIPN symptom scale widely used adults with CIPN, in pediatric HL at risk for CIPN. METHODS: Youth (11+ years) and parents of all children (5-17.9 years) with newly diagnosed high-risk HL enrolled on Children's Oncology Group AHOD1331 (NCT02166463) were invited to complete the FACT-GOG-Ntx and a health-related quality of life (HRQL) measure at pre-treatment (Time 1), and during cycles 2 (Time 2) and 5 (Time 3) of chemotherapy during the first half of study accrual. Clinical grading of CIPN by providers was also assessed using the Balis Pediatric Neuropathy Scale. We evaluated Cronbach's alpha, construct validity, and agreement between raters. Change in FACT-GOG-Ntx scores over time was assessed using a repeated measures model. RESULTS: 306 patients had at least one completed FACT-GOG-Ntx with time-specific completion rates of > 90% for both raters. Cronbach's alpha was > 0.7 for youth and parent-proxy report at all time points. Correlations between FACT-GOG-Ntx and HRQL scores were moderate (0.41-0.48) for youth and parent-proxy raters across all times. Youth and parent-proxy raters both reported worse FACT-GOG-Ntx scores at Time 3 for those who had clinically-reported CIPN compared to those who did not. Agreement between raters was moderate to high. Compared to baseline scores, those at Time 3 were significantly lower for youth (ß = - 2.83, p < 0.001) and parent-proxy raters (ß = - 1.99, p < 0.001). CONCLUSIONS: High completion rates at all time points indicated feasibility of eliciting youth and parent report. Psychometric performance of the FACT-GOG-Ntx revealed acceptable reliability, evidence of validity, and strong inter-rater agreement, supporting the use of this self- or proxy-reported measure of CIPN in youth with high-risk HL exposed to tubulin inhibitors, as part of a Phase 3 clinical trial. CLINICAL TRIAL INFORMATION: Clinical Trials Registry, NCT02166463. Registered 18 June 2014, https://clinicaltrials.gov/ct2/show/study/NCT02166463.

Single-cell RNA sequencing distinctly characterizes the wide heterogeneity in pediatric mixed phenotype acute leukemia.

BACKGROUND: Mixed phenotype acute leukemia (MPAL), a rare subgroup of leukemia characterized by blast cells with myeloid and lymphoid lineage features, is difficult to diagnose and treat. A better characterization of MPAL is essential to understand the subtype heterogeneity and how it compares with acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL). Therefore, we performed single-cell RNA sequencing (scRNAseq) on pediatric MPAL bone marrow (BM) samples to develop a granular map of the MPAL blasts and microenvironment landscape. METHODS: We analyzed over 40,000 cells from nine pediatric MPAL BM samples to generate a single-cell transcriptomic landscape of B/myeloid (B/My) and T/myeloid (T/My) MPAL. Cells were clustered using unsupervised single-cell methods, and malignant blast and immune clusters were annotated. Differential expression analysis was performed to identify B/My and T/My MPAL blast-specific signatures by comparing transcriptome profiles of MPAL with normal BM, AML, and ALL. Gene set enrichment analysis (GSEA) was performed, and significantly enriched pathways were compared in MPAL subtypes. RESULTS: B/My and T/My MPAL blasts displayed distinct blast signatures. Transcriptomic analysis revealed that B/My MPAL profile overlaps with B-ALL and AML samples. Similarly, T/My MPAL exhibited overlap with T-ALL and AML samples. Genes overexpressed in both MPAL subtypes' blast cells compared to AML, ALL, and healthy BM included MAP2K2 and CD81. Subtype-specific genes included HBEGF for B/My and PTEN for T/My. These marker sets segregated bulk RNA-seq AML, ALL, and MPAL samples based on expression profiles. Analysis comparing T/My MPAL to ETP, near-ETP, and non-ETP T-ALL, showed that T/My MPAL had greater overlap with ETP-ALL cases. Comparisons among MPAL subtypes between adult and pediatric samples showed analogous transcriptomic landscapes of corresponding subtypes. Transcriptomic differences were observed in the MPAL samples based on response to induction chemotherapy, including selective upregulation of the IL-16 pathway in relapsed samples. CONCLUSIONS: We have for the first time described the single-cell transcriptomic landscape of pediatric MPAL and demonstrated that B/My and T/My MPAL have distinct scRNAseq profiles from each other, AML, and ALL. Differences in transcriptomic profiles were seen based on response to therapy, but larger studies will be needed to validate these findings.

Single-cell analysis reveals altered tumor microenvironments of relapse- and remission-associated pediatric acute myeloid leukemia.

Acute myeloid leukemia (AML) microenvironment exhibits cellular and molecular differences among various subtypes. Here, we utilize single-cell RNA sequencing (scRNA-seq) to analyze pediatric AML bone marrow (BM) samples from diagnosis (Dx), end of induction (EOI), and relapse timepoints. Analysis of Dx, EOI scRNA-seq, and TARGET AML RNA-seq datasets reveals an AML blasts-associated 7-gene signature (CLEC11A, PRAME, AZU1, NREP, ARMH1, C1QBP, TRH), which we validate on independent datasets. The analysis reveals distinct clusters of Dx relapse- and continuous complete remission (CCR)-associated AML-blasts with differential expression of genes associated with survival. At Dx, relapse-associated samples have more exhausted T cells while CCR-associated samples have more inflammatory M1 macrophages. Post-therapy EOI residual blasts overexpress fatty acid oxidation, tumor growth, and stemness genes. Also, a post-therapy T-cell cluster associated with relapse samples exhibits downregulation of MHC Class I and T-cell regulatory genes. Altogether, this study deeply characterizes pediatric AML relapse- and CCR-associated samples to provide insights into the BM microenvironment landscape.

Automatic Personalized Impression Generation for PET Reports Using Large Language Models.

Purpose: To determine if fine-tuned large language models (LLMs) can generate accurate, personalized impressions for whole-body PET reports. Materials and Methods: Twelve language models were trained on a corpus of PET reports using the teacher-forcing algorithm, with the report findings as input and the clinical impressions as reference. An extra input token encodes the reading physician's identity, allowing models to learn physician-specific reporting styles. Our corpus comprised 37,370 retrospective PET reports collected from our institution between 2010 and 2022. To identify the best LLM, 30 evaluation metrics were benchmarked against quality scores from two nuclear medicine (NM) physicians, with the most aligned metrics selecting the model for expert evaluation. In a subset of data, model-generated impressions and original clinical impressions were assessed by three NM physicians according to 6 quality dimensions (3-point scale) and an overall utility score (5-point scale). Each physician reviewed 12 of their own reports and 12 reports from other physicians. Bootstrap resampling was used for statistical analysis. Results: Of all evaluation metrics, domain-adapted BARTScore and PEGASUSScore showed the highest Spearman's ρ correlations (ρ=0.568 and 0.563) with physician preferences. Based on these metrics, the fine-tuned PEGASUS model was selected as the top LLM. When physicians reviewed PEGASUS-generated impressions in their own style, 89% were considered clinically acceptable, with a mean utility score of 4.08 out of 5. Physicians rated these personalized impressions as comparable in overall utility to the impressions dictated by other physicians (4.03, P=0.41). Conclusion: Personalized impressions generated by PEGASUS were clinically useful, highlighting its potential to expedite PET reporting.

Medicaid expansion is associated with treatment receipt, timeliness, and outcomes among young adults with breast cancer.

Female breast cancer is a common cancer in young adults, an age group with the highest uninsured rate. Among 51 675 young adult women (ages 18-39 years) diagnosed with breast cancer between 2011 and 2018 in the National Cancer Database, we estimated changes in guideline-concordant treatment receipt, treatment timeliness, and survival associated with the Affordable Care Act Medicaid expansion. Of young adults with stage I-III estrogen receptor-positive or progesterone receptor-positive breast cancer, Medicaid expansion was associated with a net increase of 2.42 percentage points (95% confidence interval [CI] = 0.56 to 4.28 percentage points) in the percentage receiving endocrine therapy. Among all young adults with stage I-III breast cancer, Medicaid expansion was associated with a net reduction of 1.65 percentage points (95% CI = 0.08 to 3.22 percentage points) in treatment delays defined as treatment initiation of at least 60 days after diagnosis and a net increase of 1.00 percentage points (95% CI = 0.21 to 1.79 percentage points) in 2-year overall survival. Our study provides evidence of benefit in cancer care and outcomes from Medicaid expansion among the young adult population.