Children's Oncology Group's 2023 blueprint for research: Non-Hodgkin lymphoma.

Pediatric non-Hodgkin lymphoma (NHL) includes over 30 histologies (many with subtypes), with approximately 800 cases per year in the United States. Improvements in survival in NHL over the past 5 decades align with the overall success of the cooperative trial model with dramatic improvements in outcomes. As an example, survival for advanced Burkitt lymphoma is now >95%. Major remaining challenges include survival for relapsed and refractory disease and long-term morbidity in NHL survivors. Langerhans cell histiocytosis (LCH) was added to the NHL Committee portfolio in recognition of LCH as a neoplastic disorder and the tremendous unmet need for improved outcomes. The goal of the Children' Oncology Group NHL Committee is to identify optimal cures for every child and young adult with NHL (and LCH). Further advances will require creative solutions, including engineering study groups to combine rare populations, biology-based eligibility, alternative endpoints, facilitating international collaborations, and coordinated correlative biology.

Haemophagocytic lymphohistiocytosis and Epstein-Barr virus: a complex relationship with diverse origins, expression and outcomes.

Epstein-Barr virus (EBV) is a ubiquitous herpesvirus with rare but severe potential for lymphoproliferative complications. EBV is associated with a variety of presentations of haemophagocytic lymphohistiocytosis (HLH). HLH is a life-threatening hyperinflammatory syndrome that can occur in patients with genetic defects associated with dysregulation of the immune response (familial HLH) or arise in patients with underlying infection or malignancy (non-familial or secondary HLH). EBV can both serve as the incidental trigger of familial HLH or as the driving factor in patients with selective inherited vulnerability (e.g. X-linked lymphoproliferative disease). Alternatively, acute infection can idiosyncratically cause non-neoplastic HLH in patients without inherited predisposition (i.e. secondary HLH), while EBV-associated T/natural killer (NK)-cell lymphoproliferative disorders and lymphomas can cause neoplasia-associated HLH. The present review will discern between EBV-associated familial and non-familial HLH and highlight diagnostic and therapeutic considerations. Non-familial EBV-associated HLH is a major diagnostic dilemma, as it represents a diverse spectrum of disease ranging from highly curable (non-neoplastic EBV-HLH) to indolent but incurable (chronic active EBV) to acutely fatal (systemic EBV-positive T-cell lymphoma of childhood). Increased clinical awareness and understanding of this rare and potentially devastating subset of EBV-related complications is desperately needed to improve survival for patients with neoplasia-associated HLH.

Long-term outcomes for children and adolescents with Kaposi sarcoma.

OBJECTIVES: Kaposi sarcoma (KS) is one of the most common childhood cancers in eastern and central Africa. It has become a treatable disease with increasing availability of antiretroviral therapy (ART) and chemotherapy. We aimed to fill the data gap in establishing whether long-term survival is achievable for children in low-income countries. METHODS: We retrospectively analysed data for children and adolescents aged ≤ 18.9 years diagnosed with HIV-related or endemic KS from 2006 to 2015 who received standardized institutional treatment regimens utilizing chemotherapy plus ART (if HIV-positive) at a tertiary care public hospital in Lilongwe, Malawi. Long-term survival was analysed and mortality was associated with KS for those with refractory/progressive disease at the time of death. RESULTS: There were 207 children/adolescents with KS (90.8% HIV-related); 36.7% were alive, 54.6% had died, and 8.7% had been lost to follow-up. The median follow-up time for survivors was 6.9 years (range 4.2-13.9 years). Death occurred at a median of 5.3 months after KS diagnosis (range 0.1-123 months). KS progression was associated with mortality for most (61%) early deaths (survival time of < 6 months); conversely, KS was associated with a minority (31%) of late-onset deaths (after 24 months). The 7-year overall survival was 37% [95% confidence interval (CI) 30-44%] and was higher for those diagnosed between 2011 and 2015 compared to 2006-2010: 42% (95% CI 33-51%) versus 29% (95% CI 20-39%), respectively (P = 0.01). Among the 66 HIV-positive survivors, 58% were still on first-line ART. CONCLUSIONS: Long-term survival is possible for pediatric KS in low-resource settings. Despite better survival in more recent years, there remains room for improvement.

Safety analysis of high-dose methotrexate in pediatric non-Hodgkin lymphomas.

High-dose methotrexate (HD-MTX) with rigorous supportive care is essential to the treatment of pediatric non-Hodgkin lymphomas (NHL). We describe the safety and tolerability of HD-MTX in patients with NHL treated at our center. In our cohort of 46 patients, the majority had at least one course of delayed clearance and/or creatinine elevation. Additionally, more than one-third of patients experienced an episode of grade ≥3 mucositis. Creatinine elevations and delayed clearance were independently associated with subsequent grade ≥3 mucositis. We advocate for greater availability of methotrexate monitoring to allow dose escalation of this essential modality around the world.

Navigating the heterogeneous landscape of pediatric Kaposi sarcoma.

Vivid descriptions of Kaposi sarcoma (KS) occurring in children and adolescents from central and eastern Africa originated over 50 years ago. Unique clinical characteristics of pediatric KS in Africa were well described within these geographic regions that were eventually understood to be endemic for human herpesvirus-8/Kaposi sarcoma herpesvirus (HHV-8/KSHV) infection, the causative agent of KS. Having catapulted in incidence with the HIV epidemic, KS is currently among the top five most common childhood cancers in numerous countries throughout the region. The main feature that differentiates the childhood form of KS from adult disease is clinical presentation with primarily bulging lymphadenopathy. This group of patients represents the most common clinical subtype of pediatric KS in KSHV-endemic regions. Lymphadenopathic KS in children is associated with other distinct features, such as sparse occurrence of prototypical hyperpigmented cutaneous lesions, frequent presentation with severe cytopenias and a normal CD4 count, and a fulminant clinical course if untreated with chemotherapy. Increased awareness and improved recognition of lymphadenopathic KS are critically important, particularly because this subset of patients typically experiences a favorable response to chemotherapy characterized by durable complete remission. Clinical phenotypes typically observed in adult KS also occur in children-mild/moderate disease limited to cutaneous and oral involvement, woody edema, and visceral disease. This review summarizes the heterogeneous patterns of disease presentation and treatment response observed among the divergent clinical phenotypes of pediatric KS, highlights additional KSHV-related malignancies, and explores some of the potential biological drivers of such clinical phenomena.

Kaposi Sarcoma Herpesvirus Inflammatory Cytokine Syndrome-like Clinical Presentation in Human Immunodeficiency Virus-infected Children in Malawi.

We describe 7 human immunodeficiency virus-infected Malawian children with Kaposi sarcoma who met criteria for Kaposi sarcoma herpesvirus (KSHV) inflammatory cytokine syndrome. Each presented with persistent fevers, bulky lymphadenopathy, massive hepatosplenomegaly, and severe cytopenias. Plasma analyses were performed in 2 patients, both demonstrating extreme elevations of KSHV viral load and interleukin 6.

KSHV viral load and Interleukin-6 in HIV-associated pediatric Kaposi sarcoma-Exploring the role of lytic activation in driving the unique clinical features seen in endemic regions.

Kaposi sarcoma (KS) is among the most common childhood malignancies in central, eastern, and southern Africa. Although its unique clinical features have been established, biological mechanisms related to the causative agent, KS-associated herpes-virus (KSHV), have yet to be explored in children. We performed a prospective observational pilot study to explore associations between KSHV viral load (VL), human interleukin-6 (IL-6) and IL-10 levels, and clinical characteristics of 25 children with KS in Lilongwe, Malawi from June 2013-August 2015. The median age was 6.4 years. Lymphadenopathy was the most common site of KS involvement (64%), followed by skin and oral mucosa (44% each), woody edema (12%), and pulmonary (8%). Baseline samples for plasma KSHV VL, IL-6 and IL-10 analyses were available for 18/25 patients (72%) at time of KS diagnosis. KSHV VL was detectable at baseline in 12/18 (67%) patients, the median baseline IL-6 level was 8.53 pg/mL (range 4.31-28.33), and the median baseline IL-10 level was 19.53 pg/mL (range 6.91-419.69). Seven (39%) patients presented with an IL-6 level > 10 pg/mL (exceeding twice the upper limit of normal). Detectable KSHV VL was significantly associated with lymphadenopathic KS (p = 0.004), while having undetectable KSHV VL was associated with a higher likelihood of presenting with hyperpigmented skin lesions (p = 0.01). Detectable KSHV VL and elevated IL-6 levels are present in a subset of children with KS. Lytic activation of KSHV and associated elevation in KSHV VL may contribute to the unique clinical manifestations of pediatric KS in KSHV-endemic regions of Africa.

A clinicopathologic study of the spectrum of systemic forms of EBV-associated T-cell lymphoproliferative disorders of childhood: A single tertiary care pediatric institution experience in North America.

BACKGROUND: Systemic forms of EBV-associated T-cell lymphoproliferative disorders of childhood (S-EBV-T-LPD) comprise three major forms: EBV-positive hemophagocytic lymphohistiocytosis (EBV-HLH), systemic EBV-positive T-cell lymphoma (S-EBV-TCL), and systemic chronic active EBV infection (S-CAEBV). These disorders occur rarely in children in Western countries. Here, we described eight children of such entities. DESIGN: Eight cases (six clinical and two autopsy) with S-EBV-T-LPD of childhood were retrospectively identified from 1990 to 2015. Clinicopathologic parameters including histomorphology, immunophenotype, EBV studies, and T-cell receptor gene rearrangement studies were recorded. RESULTS: Patients include five females and three males of Hispanic, Asian, and Caucasian origins with an age range of 14 months to 9 years. Fever, hepatosplenomegaly, cytopenias, abnormal EBV serologies, and very high EBV viral loads were common findings. Histologic findings showed EBV+ T-cell infiltrates with variable degrees of architectural distortion and cytologic atypia ranging from no to mild cytologic atypia to overt lymphoma and tissue hemophagocytosis. All showed aberrant CD4+ or CD8+ T cells with dim to absent CD5, CD7, and CD3, and bright CD2 and CD45 by flow cytometry or loss of CD5 by immunohistochemistry. TCR gene rearrangement studies showed monoclonal rearrangements in all clinical cases (6/6). Outcomes were poor with treatment consisting of chemotherapy per the HLH-94 or HLH-2004 protocols with or without bone marrow transplant. CONCLUSION: In this large pediatric clinicopathologic study of S-EBV-T-LPD of childhood in the United States, EBV-HLH, S-EBV-TCL, and S-CAEBV show many overlapping features. Diagnosis is challenging, and overall outcome is poor using current HLH-directed therapies.

Plasma Epstein-Barr virus DNA for pediatric Burkitt lymphoma diagnosis, prognosis and response assessment in Malawi.

Point-of-care tools are needed in sub-Saharan Africa (SSA) to improve pediatric Burkitt lymphoma (BL) diagnosis and treatment. We evaluated plasma Epstein-Barr virus (pEBV) DNA as a pediatric BL biomarker in Malawi. Prospectively enrolled children with BL were compared to classical Hodgkin lymphoma (cHL) and nonlymphoma diagnoses. Pediatric BL patients received standardized chemotherapy and supportive care. pEBV DNA was measured at baseline, mid-treatment, and treatment completion. Of 121 assessed children, pEBV DNA was detected in 76/88 (86%) with BL, 16/17 (94%) with cHL, and 2/16 (12%) with nonlymphoma, with proportions higher in BL versus nonlymphoma (p < 0.001) and similar in BL versus cHL (p = 0.69). If detected, median pEBV DNA was 6.1 log10 copies/mL for BL, 4.8 log10 copies/mL for cHL, and 3.4 log10 copies/mL for nonlymphoma, with higher levels in BL versus cHL (p = 0.029), and a trend toward higher levels in BL versus nonlymphoma (p = 0.062). pEBV DNA declined during treatment in the cohort overall and increased in several children before clinical relapse. Twelve-month overall survival was 40% in the cohort overall, and for children with baseline pEBV detected, survival was worse if baseline pEBV DNA was ≥6 log10 copies/mL versus <6 log10 copies/mL (p = 0.0002), and also if pEBV DNA was persistently detectable at mid-treatment versus undetectable (p = 0.041). Among children with baseline pEBV DNA detected, viremia was the only significant risk factor for death by 12 months in multivariate analyses (adjusted hazard ratio 1.35 per log10 copies/mL, 95% CI 1.04-1.75, p = 0.023). Quantitative pEBV DNA has potential utility for diagnosis, prognosis, and response assessment for pediatric BL in SSA.

Hodgkin lymphoma, HIV, and Epstein-Barr virus in Malawi: Longitudinal results from the Kamuzu Central Hospital Lymphoma study.

BACKGROUND: Contemporary descriptions of classical Hodgkin lymphoma (cHL) are lacking from sub-Saharan Africa where human immunodeficiency virus (HIV) and Epstein-Barr virus (EBV) are prevalent. METHODS: We describe a prospective cHL cohort in Malawi enrolled from 2013 to 2015. Patients received standardized treatment and evaluation, including HIV status and EBV testing of tumors and plasma. RESULTS: Among 31 patients with confirmed cHL, the median age was 19 years (range, 2-51 years) and 22 (71%) were male. Sixteen patients (52%) had stage III/IV, 25 (81%) B symptoms, and 16 (52%) performance status impairment. Twenty-three patients (74%) had symptoms >6 months, and 11 of 29 (38%) had received empiric antituberculosis treatment. Anemia was common with median hemoglobin 8.2 g/dL (range, 3.1-17.1 g/dL), which improved during treatment. No children and 5 of 15 adults (33%) were HIV+. All HIV+ patients were on antiretroviral therapy for a median 15 months (range, 2-137 months), with median CD4 count 138 cells/µL (range, 23-329 cells/µL) and four (80%) having undetectable HIV. EBV was present in 18 of 24 (75%) tumor specimens, including 14 of 20 (70%) HIV- and 4 of 4 (100%) HIV+. Baseline plasma EBV DNA was detected in 25 of 28 (89%) patients, with median viral load 4.7 (range, 2.0-6.7) log10 copies/mL, and subsequently declined in most patients. At 12 months, overall survival was 75% (95% confidence interval [CI], 55%-88%) and progression-free survival 65% (95% CI, 42%-81%). Baseline plasma EBV DNA and persistent viremia during treatment were associated with poorer outcomes. CONCLUSION: cHL in Malawi is characterized by delayed diagnosis and advanced disease. Most cases were EBV associated and one-third of adults were HIV+. Despite resource limitations, 12-month outcomes were good.

Identifying opportunities to bridge disparity gaps in curing childhood cancer in Malawi: Malignancies with excellent curative potential account for the majority of diagnoses.

The majority of African children with cancer die without access to resources. We describe efforts to build a public treatment program with curative intent for childhood cancer in Lilongwe, Malawi despite severe limitations in diagnostic and therapeutic resources. We retrospectively analyzed a cohort of childhood cancer patients at Kamuzu Central Hospital from 12/2011-6/2013. Consistently available chemotherapeutic agents were limited to cyclophosphamide, vincristine, doxorubicin, bleomycin, methotrexate, and prednisone. Of 258 newly diagnosed childhood malignancies, 17 patients with retinoblastoma were excluded from clinical analyses due to insufficient clinical data. Among the remainder of the cohort (n = 241), 42% were female with median age 8.4 years (range 0.6-17.9). Forty-six (19%) were HIV-infected (42 Kaposi sarcoma, 3 Burkitt lymphoma, 1 Hodgkin lymphoma). The most common clinical presentations were palpable abdominal mass (41%), peripheral lymphadenopathy (33%), and jaw mass (17%). Nearly two-thirds of total diagnoses were accounted for by Burkitt lymphoma (n = 74), Kaposi sarcoma (n = 52), Hodgkin lymphoma (n = 21), and Wilms tumor (n = 19). Twelve-month overall survival for these 4 most common diagnoses was 54% (95% confidence interval 46-61) versus 19% (95% confidence interval 11-30) for all other diagnoses (median follow-up 19 months). Treatment-related mortality was highest in patients with non-Wilms solid tumors of the abdomen (48% versus 10% for the overall cohort, p < 0.001), while treatment abandonment was highest in patients with bone and soft-tissue sarcomas (29% versus 14% overall, p = 0.05). Childhood cancers with excellent curative potential accounted for the majority of patients, establishing an opportunity to build treatment programs with curative intent despite severe limitations.

Adolescent and young adult non-Hodgkin lymphoma.

Non-Hodgkin lymphoma (NHL) is a heterogeneous group of lymphoid malignancies accounting for a significant portion of cancers occurring in children, adolescents and young adults with an increasing incidence with age. The adolescent and young adult (AYA) population presents a specific set of characteristics and challenges. The most common diseases occurring in adolescents and young adults include Burkitt lymphoma, lymphoblastic lymphoma, diffuse large B-cell lymphoma, anaplastic large cell lymphoma and primary mediastinal B-cell lymphoma. There is also a higher incidence of primary central nervous system lymphoma in AYA patients. Cure rates largely depend on risk-stratification, and are generally superior to outcomes in comparison to older adult data but less than in younger children. Here, we review the unique clinical and biological characteristics of NHL occurring in the AYA population with a focus on how to achieve similar curative outcomes in AYA that have been established in younger cohorts.

Advances in the diagnosis and treatment of childhood and adolescent B-cell non-Hodgkin lymphoma.

Burkitt lymphoma and diffuse large B-cell lymphoma represent the majority of mature B-cell non-Hodgkin lymphomas in children, adolescents, and young adults. Although they are characterized by specific clinical and biological nuances, the 2 diseases share significant clinicopathologic overlap and are treated with the same chemotherapy regimens in pediatrics. Modern-day chemotherapy protocols achieve overall event-free survival rates of nearly 90%. The addition of the anti-CD20 monoclonal antibody rituximab to backbone chemotherapy holds great promise for improving long-term curative outcomes while diminishing acute and long-term toxicities. However, in the contemporary era, the long-term survival for patients with relapsed or refractory disease is meager. The role of hematopoietic stem cell transplantation in children, adolescents, and young adults with relapsed/refractory disease is currently being defined. Meanwhile, novel humoral and cellular immunotherapies, as well as agents targeting specific molecular pathways that drive lymphomagenesis, are exciting developments that are being evaluated in clinical trials.

SMARCA4 is a haploinsufficient B cell lymphoma tumor suppressor that fine-tunes centrocyte cell fate decisions.

SMARCA4 encodes one of two mutually exclusive ATPase subunits in the BRG/BRM associated factor (BAF) complex that is recruited by transcription factors (TFs) to drive chromatin accessibility and transcriptional activation. SMARCA4 is among the most recurrently mutated genes in human cancer, including ∼30% of germinal center (GC)-derived Burkitt lymphomas. In mice, GC-specific Smarca4 haploinsufficiency cooperated with MYC over-expression to drive lymphomagenesis. Furthermore, monoallelic Smarca4 deletion drove GC hyperplasia with centroblast polarization via significantly increased rates of centrocyte recycling to the dark zone. Mechanistically, Smarca4 loss reduced the activity of TFs that are activated in centrocytes to drive GC-exit, including SPI1 (PU.1), IRF family, and NF-κB. Loss of activity for these factors phenocopied aberrant BCL6 activity within murine centrocytes and human Burkitt lymphoma cells. SMARCA4 therefore facilitates chromatin accessibility for TFs that shape centrocyte trajectories, and loss of fine-control of these programs biases toward centroblast cell-fate, GC hyperplasia and lymphoma.

Clinical characteristics and outcomes of HIV-infected children diagnosed with Kaposi sarcoma in Malawi and Botswana.

BACKGROUND: Kaposi sarcoma (KS) is the most common HIV-associated malignancy in sub-Saharan Africa. The presentation and outcomes of pediatric KS are not well understood. PROCEDURE: We performed a retrospective cohort analysis of 81 HIV-infected children with KS at the Baylor Children's Clinical Centres of Excellence in Malawi and Botswana from March 2003 to October 2009. RESULTS: Eighty-one children with KS were identified whose median age was 8.0 (inter-quartile range 5.1-11.3) years. KS lesions were presented primarily on the skin (83%), lymph nodes (52%), and oral mucosa (41%). Occasionally disease was limited to the lymph nodes only (10%). Severe immunosuppression (70%), anemia (29%), and thrombocytopenia (17%) were common laboratory findings. Highly active antiretroviral therapy (HAART) was administered to 94% of children, including 77% who received HAART plus chemotherapy. KS immune reconstitution inflammatory syndrome (IRIS) occurred in 22%. Disease status 12 months after KS diagnosis was determined for 69 children: 43% were alive and 57% had died. Severe immunosuppression was independently associated with mortality in multivariate analysis (OR = 4.3; 95% CI 1.3-14.6; P = 0.02). CONCLUSION: KS occurs in a significant number of HIV infected children in sub-Saharan Africa. Pediatric KS is distinct from KS in adults. Lymph node involvement was a common manifestation of KS in children, and severe immunosuppression was associated with the highest mortality risk. Though overall mortality was high in children with KS, patients did achieve clinical remission in settings with limited diagnostic and therapeutic resources.

Diagnosis and management of cutaneous lymphomas and lymphoid proliferations in children, adolescents and young adults (CAYA).

Cutaneous lymphomas and lymphoid proliferations (LPD) in children, adolescents, and young adults (CAYA) are a heterogeneous group of lymphoid neoplasms that present formidable diagnostic challenges to clinicians and pathologists alike. Although rare overall, cutaneous lymphomas/LPD occur in real-world settings and awareness of the differential diagnosis, potential complications, and various therapeutic approaches will help ensure the optimal diagnostic work-up and clinical management. Lymphomas/LPD involving the skin can occur as primary cutaneous disease in a patient that characteristically has lymphoma/LPD confined to the skin, or as secondary involvement in patients with systemic disease. This review will comprehensively summarize both primary cutaneous lymphomas/LPD that occur in the CAYA population as well as those CAYA systemic lymphomas/LPD with propensity for secondary cutaneous involvement. Focus on the most common primary entities occurring in CAYA will include lymphomatoid papulosis, primary cutaneous anaplastic large cell lymphoma, mycosis fungoides, subcutaneous panniculitis-like T-cell lymphoma, and hydroa vacciniforme lymphoproliferative disorder.

Mature B-cell lymphomas in adolescents and young adults.

Pediatric non-Hodgkin lymphoma includes over 30 histologies (many with subtypes), with approximately 800 cases per year in the US, compared to >60,000 cases of adult NHL annually. Improvements in survival in pediatric and adolescent mature B cell NHL over the past 5 decades align with the overall success of the cooperative trial model with dramatic improvements in outcomes through dose escalation of chemotherapy and, more recently, targeted therapy with rituximab. Pediatric dose-intense strategies carry risks of long-term consequences, but treatment failure is nearly universally fatal. By comparison, adult mature B cell lymphoma is typically less aggressive and treated with less intense chemotherapy. Optimizing therapy for adolescents and young adults remains a major challenge that requires creative solutions, including engineering study groups to combine biologically comparable adult and pediatric populations and developing effective salvage strategies that will ultimately be required for investigations of front-line dose reduction. In this review, we discuss challenges and opportunities for improving outcomes for adolescents and young adults with high-grade mature B cell lymphomas, diffuse large B cell lymphoma, and primary mediastinal B cell lymphoma.

Pediatric HIV+ Kaposi sarcoma exhibits clinical, virological, and molecular features different from the adult disease.

BACKGROUNDKaposi sarcoma (KS) is among the most common childhood cancers in Eastern and Central Africa. Pediatric KS has a distinctive clinical presentation compared with adult KS, which includes a tendency for primary lymph node involvement, a considerable proportion of patients lacking cutaneous lesions, and a potential for fulminant disease. The molecular mechanisms or correlates for these disease features are unknown.METHODSThis was a cross-sectional study. All cases were confirmed by IHC for KS-associated herpesvirus (KSHV) LANA protein. Baseline blood samples were profiled for HIV and KSHV genome copy numbers by qPCR and secreted cytokines by ELISA. Biopsies were characterized for viral and human transcription, and KSHV genomes were determined when possible.RESULTSSeventy participants with pediatric KS were enrolled between June 2013 and August 2019 in Malawi and compared with adult patients with KS. They exhibited high KSHV genome copy numbers and IL-6/IL-10 levels. Four biopsies (16%) had a viral transcription pattern consistent with lytic viral replication.CONCLUSIONThe unique features of pediatric KS may contribute to the specific clinical manifestations and may direct future treatment options.FUNDINGUS National Institutes of Health U54-CA-254569, PO1-CA019014, U54-CA254564, RO1-CA23958.