Single cell RNA-sequencing of Ewing sarcoma tumors demonstrates transcriptional heterogeneity and clonal evolution.

Ewing sarcoma is the second most common bone cancer in children, accounting for 2% of pediatric cancer diagnoses. Patients who present with metastatic disease at the time of diagnosis have a dismal prognosis, compared to the >70% 5-year survival of those with localized disease. Here, we utilized single cell RNA-sequencing to characterize the transcriptional landscape of primary Ewing sarcoma tumors and surrounding tumor microenvironment (TME). Copy-number analysis identified subclonal evolution within patients even prior to treatment. Primary tumor samples demonstrate a heterogenous transcriptional landscape with several conserved gene expression programs, including those composed of genes related to proliferation and EWS targets. We also were able to identify the composition of the TME and molecularly dissect the transcriptional profile of circulating tumor cells in peripheral blood at the time of diagnosis.

Predictors of survival following liver transplantation for pediatric hepatoblastoma and hepatocellular carcinoma: Experience from the Society of Pediatric Liver Transplantation (SPLIT).

Management of unresectable pediatric hepatoblastoma (HB) and hepatocellular carcinoma (HCC) remains challenging. The Society of Pediatric Liver Transplantation (SPLIT) database was used to study survival predictors in pediatric liver transplantation (LT) for HB and HCC. Event-free survival (EFS), associated risk factors, and postoperative complications were studied in children requiring LT for HB/HCC at 16 SPLIT centers. Three-year EFS was 81% for HB (n = 157) and 62% for HCC (n = 18) transplants. Of HB transplants, 6.9% were PRETEXT II and 15.3% were POST-TEXT I/II. Tumor extent did not impact survival (p = NS). Salvage (n = 13) and primary HB transplants had similar 3-year EFS (62% versus 78%, p = NS). Among HCC transplants, 3-year EFS was poorer in older patients (38% in ≥8-year-olds vs 86% <8-year-olds) and those with larger tumors (48% for those beyond versus 83% within Milan criteria, p = NS). Risk of infection (HR 1.5, 95% CI 1.1-2.2, p = .02) and renal injury (HR 2.4, 95% CI 1.7-3.3, p < .001) were higher in malignant versus nonmalignant LT. Survival is favorable for pediatric HB and HCC LT, including outcomes after salvage transplant. Unexpected numbers of LTs occurred in PRE/POST-TEXT I/II tumors. Judicious patient selection is critical to distinguish tumors that are potentially resectable; simultaneously, we must advocate for patients with unresectable malignancies to receive organs.

Circulating Plasma Tumor DNA Is Superior to Plasma Tumor RNA Detection in Ewing Sarcoma Patients: ptDNA and ptRNA in Ewing Sarcoma.

The detection of tumor-specific nucleic acids from blood increasingly is being used as a method of liquid biopsy and minimal residual disease detection. However, achieving high sensitivity and high specificity remains a challenge. Here, we perform a direct comparison of two droplet digital PCR (ddPCR)-based detection methods, circulating plasma tumor RNA and circulating plasma tumor DNA (ptDNA), in blood samples from newly diagnosed Ewing sarcoma patients. First, we developed three specific ddPCR-based assays to detect EWS-FLI1 or EWS-ERG fusion transcripts, which naturally showed superior sensitivity to DNA detection on in vitro control samples. Next, we identified the patient-specific EWS-FLI1 or EWS-ERG breakpoint from five patient tumor samples and designed ddPCR-based, patient-specific ptDNA assays for each patient. These patient-specific assays show that although plasma tumor RNA can be detected in select newly diagnosed patients, positive results are low and statistically unreliable compared with ptDNA assays, which reproducibly detect robust positive results across most patients. Furthermore, the unique disease biology of Ewing sarcoma enabled us to show that most cell-free RNA is not tumor-derived, although cell-free-DNA burden is affected strongly by tumor-derived DNA burden. Here, we conclude that, even with optimized highly sensitive and specific assays, tumor DNA detection is superior to RNA detection in Ewing sarcoma patients.

A Cystic Renal Mass in the Setting of a Pneumothorax: More Than Meets the Eye?

DICER1 syndrome is a rare hereditary cancer predisposition syndrome that has relevance to pediatric urology providers due to its association with many various pediatric genitourinary malignancies. We describe the case of a pediatric patient who was eventually diagnosed with a pathogenic DICER1 germline variant after undergoing resection of a cystic nephroma and pleuropulmonary blastoma.

Metastatic NUT Midline Carcinoma Treated With Aggressive Neoadjuvant Chemotherapy, Radiation, and Resection: A Case Report and Review of the Literature.

NUT midline carcinoma, characterized by the rearrangement of the nuclear protein in testis (NUTM1) gene, is a rare and aggressive subtype of squamous cell carcinoma. This disease is rarely cured and there have been no reports of cure in patients with distant metastatic disease. In fact, patients typically succumb to NUT midline carcinoma within 6 to 12 months from diagnosis. The authors report on a single patient who presented widely metastatic disease who has now been in remission for 37 months after multimodal therapy with compressed cycles of vincristine, cyclophosphamide, and doxorubicin alternating with ifosfamide and etoposide, high-dose radiation, and postchemotherapy resection.

Central Nervous System Involvement of Rhabdomyosarcoma: A Single Institution Experience.

The incidence of central nervous system (CNS) involvement in patients with rhabdomyosarcoma (RMS) is low, and the outcome is dismal. We present a single institution analysis of CNS involvement of pediatric RMS. In 59 patients, the prevalence of CNS involvement was 11.9% (7 patients), higher than prior reports. Of the 6 deaths from disease, all had rapid progression, with a median survival of 14 days. The higher incidence could be secondary to treatment modifications or more sensitive detection. These findings are useful for decisions at the time of CNS involvement and could lead to modifications for future RMS clinical trials.

Timing of Radiation Therapy in Pediatric Wilms Tumor: A Report From the National Cancer Database.

PURPOSE: To determine, using the National Cancer Database (NCDB), the impact of the surgery to radiation therapy interval (SRI) on survival in contemporary patients with Wilms tumor (WT). METHODS AND MATERIALS: The NCDB was queried for patients aged ≤25 years diagnosed from 2004 to 2013 with unilateral WT who underwent definitive surgery and radiation therapy. The SRI was calculated for each patient. A stratified analysis was performed based on presence of metastasis using logistic regression to calculate risk factors for prolonged SRI, with a focus on the recommended SRI according to recent Children's Oncology Group trials (by day 14) and National Wilms Tumor Study-5 (by day 9). Cox regression was performed to assess the association of SRI with overall survival. RESULTS: A total of 1488 patients were included; 32.1% had metastasis at diagnosis. Among both metastatic and nonmetastatic groups, older patients were more likely to have prolonged SRI. For those without metastasis, SRI > 14 days was associated with increased risk of mortality (hazard ratio 2.13, P = .013). Analyzing SRI as a continuous variable also demonstrated an increased risk of death with longer SRI (hazard ratio 1.04 per day, P = .006) in this group. In contrast, among patients with metastasis, no significant association between SRI and mortality was found. CONCLUSION: Early initiation of radiation therapy remains a critical component of multimodal treatment for patients with nonmetastatic WT. For nonmetastatic patients, SRI ≤ 14 days correlates with improved overall survival. However, no such association was noted for patients with metastases. These results may inform the development of future WT trials.

Patterns of care and survival outcomes for adolescent and young adult patients with testicular seminoma in the United States: A National Cancer Database analysis.

INTRODUCTION: Testicular germ cell tumors (GCTs) are the most common solid tumor among adolescent and young adult (AYA) males. AYA patients with GCTs most typically have non-seminoma compared with seminoma, and accordingly there are fewer data reported on the AYA experience with testicular seminoma. OBJECTIVE: To evaluate national trends in postoperative treatment and overall survival (OS) outcomes in testicular seminoma by age group, specifically comparing AYAs with older adults. STUDY DESIGN: The National Cancer Data Base (NCDB) was queried for patients with testicular seminoma diagnosed between 2004 and 2012, who underwent orchiectomy followed by observation or adjuvant therapy (chemotherapy, radiation (RT), or both). Patients were grouped by age: AYA (15-39 years), adults between 40 and 55 years, and adults >55 years. Overall survival (OS) was presented using Kaplan-Meier curves and groups compared via a log-rank test. Univariate (UVA) and multivariate (MVA) analyses were performed using Cox proportional hazards regression models. Binary multiple logistic regression identified differences in variables by age category. RESULTS: Of the total 22,361 patients the majority were AYAs (12,880, 57.6%), followed by adults 40-55 years (8,022, 35.9%), and >55 years (1,459, 6.5%). Unadjusted 5-year OS was significantly better for AYAs versus adults 40-55 years and >55 years (98.0%, 96.4%, 87.7%; p < 0.001), as was 10-year OS (96.1%, 91.8%, 71.3% respectively; p < 0.001). The Table shows that on a MVA, OS was significantly better for AYAs versus adults 40-55 years and adults >55 years. AYA patients were also more commonly treated at centers with greater clinical volume. Additionally, AYA patients were less likely to present with metastatic disease. Accordingly, AYA patients were less likely to undergo retroperitoneal lymph node dissection (OR 0.81; p = 0.001) and were less often managed with adjuvant therapy including chemotherapy (OR 0.91; p = 0.027), RT (OR 0.93; p = 0.025), or both (OR 0.68; p = 0.020). DISCUSSION: AYA patients with testicular seminoma present with earlier stage disease and in the clinical Stage I setting are more often are managed with active surveillance following orchiectomy when compared with older adults in this population-based analysis. Among AYA patients, OS was modestly better when compared with adults 40-55 years and significantly better when compared with adults >55 years. CONCLUSION: Our objective to describe the patterns of care and survival outcomes for AYA patients with testicular seminoma in the USA was met by reviewing this large national dataset. These results may inform future guidelines for management of AYA seminoma.

Reliability of intraoperative frozen section for the diagnosis of renal tumors suspicious for malignancy in children and adolescents.

BACKGROUND: The ability of intraoperative frozen section (IFS) to reliably diagnose renal tumors in children and adolescents is largely unknown. The objective of our study is to evaluate the ability of IFS to establish a histologic diagnosis for renal tumors in this population. METHODS: We reviewed our experience with patients who underwent IFS at the time of surgery for a renal tumor suspicious for malignancy from 2005 to 2015. The IFS was compared to the final pathology (FP). Data on concordance and reliability were analyzed. RESULTS: One hundred thirty patients underwent surgical interventions for a renal tumor suspicious for malignancy, and 32 (25%) patients underwent IFS. Median turnaround time for IFS was 20 min (range 13-44). The histologic IFS diagnosis correlated with FP in 26 (81.2%) cases was discrepant in three (9.4%) cases, and IFS was deferred to FP in three (9.4%) cases (kappa 0.71, 95% confidence interval [CI]: 0.52-0.899, P < 0.001). The IFS correctly distinguished between Wilms tumor and non-Wilms tumor in 30 (94%) cases (kappa 0.874, 95% CI: 0.705-1, P < 0.001). A total of 17 of 19 (89.5%) Wilms tumors were correctly diagnosed by IFS, yielding a sensitivity of 0.89 (95% CI: 0.67-0.99) and a specificity of 1 (95% CI: 0.75-1). CONCLUSION: IFS is a reliable tool to establish a histologic diagnosis and to differentiate between Wilms and non-Wilms tumors in children and adolescents with renal tumors. The use of IFS should be encouraged in cases in which obtaining a diagnosis will provide guidance for important "real-time" medical decision making, specifically additional adjunctive surgical procedures.

Survival outcomes of adolescent and adult patients with non-seminomatous testicular germ-cell tumors: A population-based study.

BACKGROUND: In adolescents, approximately 90% of testicular germ cell tumors (T-GCTs) are non-seminomas (NS T-GCTs). Few studies have evaluated the impact of age, specifically in adolescence, on outcomes of NS T-GCTs. OBJECTIVE: The purpose of this study was to review all patients diagnosed with NS T-GCTs in the Surveillance, Epidemiology, and End Results (SEER) database to evaluate the association between age (adolescents vs. adults) and survival outcomes. METHOD: The SEER database was queried for individuals ≥13 years old diagnosed with NS T-GCTs from 1995 to 2012. Patients were categorized into adolescent (13-19 years) and adult (≥20 years) cohorts. A Cox proportional hazards model was used for multivariate analysis (MVA). RESULTS: A total of 13,963 patients (1496 adolescents, 12,467 adults) was included. Median follow-up was 71 months (range 1-215). Five-year overall survival (OS) for adolescent and adult patients was 94% and 92%, respectively (p = 0.007); 5-year cancer-specific survival (CSS) was 95% and 94%, respectively (p = 0.139). Under MVA, adolescent patients had improved OS (HR 0.61; 95% CI 0.50-0.75; p < 0.001) and CSS (HR 0.65; 95% CI 0.51-0.82; p < 0.001), when compared with adults (Table). In a logistic regression analysis adjusting for demographics, adolescent patients were more likely to present with regional or distant metastatic disease (OR 1.16; 95% CI 1.01-1.35; p = 0.039), undergo an orchiectomy (OR 2.44; 95% CI 1.50-4.00; p < 0.001) or tumor excision (OR 2.43; 95% CI 1.57-3.77; p < 0.001), and receive other adjuvant surgery (OR 5.87; 95% CI 2.25-15.30; p < 0.001). CONCLUSIONS: To our knowledge, this is the largest population-based comparative analysis in NS T-GCTs comparing outcomes between these two age groups. Adolescent patients with NS T-GCTs had slightly improved survival compared with adults, despite presenting with more advanced disease. While adolescent patients present at more advanced stage, they achieve excellent survival outcomes possibly at the cost of a greater therapeutic burden.

Cardiac Mortality in Children and Adolescents with Hodgkin's Lymphoma: A Surveillance, Epidemiology and End Results Analysis.

PURPOSE: The purpose of this study was to evaluate the risk of cardiac death in pediatric Hodgkin's lymphoma (HL) survivors and identify high-risk groups that may need additional surveillance. METHODS: The Surveillance, Epidemiology and End Results program database was queried to analyze the rates of radiation therapy (RT) use and cardiac-specific mortality (CSM) in HL patients, aged 0-21 years, treated from 1973 to 2007. Primary endpoint was cardiac mortality. RESULTS: A total of 6552 patients were included. Median follow-up was 12 years (range, 0-40). Median age at diagnosis was 17 years (range, 0-21). The majority were white (85.5%), from western states (41.2%), had nodular sclerosis HL (73.2%), presented with stage I or II disease (51.5%), and received RT (56.1%). Death from cardiac disease occurred in 114 patients (9.2% of all deaths). CSM for the entire cohort at 10-, 20-, and 30-year time points was 0.3%, 1.6%, and 5.0%, respectively. Median age at the time of cardiac death was 39 years (range, 18-58 years). Under multivariate analysis (MVA), adolescent patients (ages 13-21) had higher rates of CSM (hazard ratio [HR], 3.05; p = 0.005). Female gender (HR, 0.43; p < 0.001), patients treated from 1998 to 2007 (HR, 0.19; p = 0.018), and those with lymphocyte-rich histology (HR, 0.14; p = 0.047) had significantly lower rates of CSM. Use of RT was not associated with CSM under MVA (HR, 1.18, p = 0.452). CONCLUSION: The cumulative incidence of CSM in this population analysis of pediatric HL was 9.2%, with a steady decline over the past several decades. Adolescent patients at diagnosis and males were more likely to die of cardiac-related causes.

Development of a Primary Care-Based Clinic to Support Adults With a History of Childhood Cancer: The Tactic Clinic.

PURPOSE: Describe the development and evolution of a primary-care-based, multidisciplinary clinic to support the ongoing care of adult survivors of childhood cancer. METHODS: A consultative clinic for adult survivors of childhood cancer has been developed that is located in an adult, academic internal medicine setting and is based on a long-term follow-up clinic model available at Children's Hospital Colorado. RESULTS: The clinic opened in July 2008. One hundred thirty-five patients have been seen as of April 2014. Referrals and clinic capacity have gradually increased over time, and a template has been developed in the electronic medical record to help facilitate completion of individualized care plan letters. CONCLUSIONS: A primary care-based, multidisciplinary consultative clinic for adults with a history of childhood cancer survivor is feasible and actively engages adult primary care resources to provide risk-based care for long-term pediatric cancer survivors. This model of care planning can help support adult survivors of pediatric cancer and their primary care providers in non-academic, community settings as well.

Non-Rhabdomyosarcoma Soft Tissue Sarcomas in Children: A Surveillance, Epidemiology, and End Results Analysis Validating COG Risk Stratifications.

PURPOSE: Non-rhabdomyosarcoma soft tissue sarcomas (NRSTS) are a heterogeneous group of sarcomas that encompass over 35 histologies. With an incidence of ∼500 cases per year in the United States in those <20 years of age, NRSTS are rare and therefore difficult to study in pediatric populations. We used the large Surveillance, Epidemiology, and End Results (SEER) database to validate the prognostic ability of the Children's Oncology Group (COG) risk classification system and to define patient, tumor, and treatment characteristics. METHODS AND MATERIALS: From SEER data from 1988 to 2007, we identified patients ≤18 years of age with NRSTS. Data for age, sex, year of diagnosis, race, registry, histology, grade, primary size, primary site, stage, radiation therapy, and survival outcomes were analyzed. Patients with nonmetastatic grossly resected low-grade tumors of any size or high-grade tumors ≤5 cm were considered low risk. Cases of nonmetastatic tumors that were high grade, >5 cm, or unresectable were considered intermediate risk. Patients with nodal or distant metastases were considered high risk. RESULTS: A total of 941 patients met the review criteria. On univariate analysis, black race, malignant peripheral nerve sheath (MPNST) histology, tumors >5 cm, nonextremity primary, lymph node involvement, radiation therapy, and higher risk group were associated with significantly worse overall survival (OS) and cancer-specific survival (CSS). On multivariate analysis, MPNST histology, chemotherapy-resistant histology, and higher risk group were significantly poor prognostic factors for OS and CSS. Compared to low-risk patients, intermediate patients showed poorer OS (hazard ratio [HR]: 6.08, 95% confidence interval [CI]: 3.53-10.47, P<.001) and CSS (HR: 6.27; 95% CI: 3.44-11.43, P<.001), and high-risk patients had the worst OS (HR: 13.35, 95% CI: 8.18-21.76, P<.001) and CSS (HR: 14.65, 95% CI: 8.49-25.28, P<.001). CONCLUSIONS: The current COG risk group stratification for children with NRSTS has been validated with a large number of children in the SEER database.

Dual ALK and MYC rearrangements leading to an aggressive variant of anaplastic large cell lymphoma.

Anaplastic lymphoma kinase (ALK) and MYC are oncogenes often dysregulated in pediatric lymphomas. NPM-ALK/t(2;5)(p23;q35) is a genetic hallmark of ALK anaplastic large cell lymphoma (ALCL). MYC gene translocations are frequently detected in high-grade B-cell lymphomas. ALKALCL cases with concurrent MYC translocation are exceedingly rare and are more aggressive and chemoresistent compared with other ALKALCL. We report a patient who presented with ALKALCL possessing coexistent MYC rearrangement, massive tumor dissemination, and early widespread relapse. This case underscores the importance of recognition of close correlation between dual ALK and MYC rearrangements and the characteristic clinical features in this unusual ALCL variant.

Successful pulmonary artery embolectomy in a patient with a saddle Wilms tumor embolus.

Denys-Drash syndrome is a genetic disorder characterized by ambiguous genitalia, cryptorchidism, nephrotic syndrome, and a high predilection for Wilms tumor with intravascular invasion. We report a 5-year-old male with Denys-Drash syndrome who rapidly developed Wilms tumor with vascular invasion, subsequent saddle tumor embolus, and required emergent embolectomy. This case illustrates the rapid emergence of Wilms tumor in a patient with Denys-Drash syndrome and the importance of considering embolectomy over thrombolytic therapy for PE in this population, given a high likelihood of tumor embolus.

Local control of metastatic sites with radiation therapy in metastatic Ewing sarcoma and rhabdomyosarcoma.

Approximately 20% of children with Ewing sarcoma (EWS) and rhabdomyosarcoma (RMS) present with metastatic disease at initial diagnosis. Overall, the outcome is poor, with an event-free survival of < 20%. Local control at metastatic sites has not been previously reported. We reviewed control of metastatic sites in children with EWS and RMS that received curative intent radiation therapy to each metastatic site. In 13 children, at a median follow-up of 18 months, a single local failure was seen. Toxicity was minimal. Our data suggest that radiation therapy is effective and tolerable in children with metastatic EWS and RMS.

Gray zone lymphomas in pediatric patients.

Gray zone lymphomas are defined as lymphoid malignancies that cannot be reliably classified into a single distinct disease entity after all available morphologic, immunophenotypic, and molecular investigations have been performed. The 2008 World Health Organization Classification proposed 2 gray zone lesions: (1) B-cell lymphoma, unclassifiable, with features intermediate between diffuse large B-cell lymphoma and Burkitt lymphoma and (2) B-cell lymphoma, unclassifiable, with features intermediate between diffuse large B-cell lymphoma and classical Hodgkin lymphoma. These gray zone lesions are rare, especially in pediatric patients, and create a great challenge to both pathologists and oncologists because this differential diagnosis has direct implications for management strategies. In this manuscript, we report 2 cases of pediatric patients with gray zone lymphoma and review clinicopathologic features, treatment options, and outcomes of this uncommon tumor.

Acute tumor lysis syndrome in a 7-month-old with hepatoblastoma.

Acute tumor lysis syndrome (TLS) is characterized by the triad of hyperuricemia, hyperkalemia, and hyperphosphatemia and is caused by the death of tumor cells and release of intracellular contents into the circulation. This syndrome is most frequently associated with hematopoietic malignancies with a high growth fraction, including acute leukemias and lymphomas, but can be encountered in patients with nonhematopoietic solid tumors. Acute tumor lysis is typically precipitated by chemotherapy leading to rapid cell death, but may also occur spontaneously prior to treatment. In severe cases, the metabolic abnormalities of TLS can cause renal failure, cardiac arrhythmias, and death. Standard therapies include intravenous hydration, alkalinization of the urine to increase the solubility of uric acid, and administration of allopurinol to block production of uric acid. Recombinant urate oxidase (rasburicase) is a newer agent that directly cleaves uric acid. It is important for the clinician to maintain a high level of clinical suspicion for TLS when initiating therapy in children newly diagnosed with cancer, including those with solid tumors, and to know how to prevent and treat this potentially deadly metabolic complication.

Precursor natural killer cell leukemia.

Natural killer (NK) cell tumors are a rare and heterogeneous group of disorders. Immature NK cell tumors are less common, and are less recognized and defined than mature NK cell tumors. There is insufficient experience of diagnosis and treatment with immature NK cell tumors, especially in pediatric patients. Here we describe a pediatric patient with precursor NK cell leukemia and review the literature of the previously reported cases in children to further help characterize the diagnosis, treatment, and outcome.

Upfront window trial of topotecan in previously untreated children and adolescents with poor prognosis metastatic osteosarcoma: children's Cancer Group (CCG) 7943.

BACKGROUND: Patients with metastatic osteosarcoma have a poor prognosis. The objectives of the study were to determine the antitumor activity and toxicity of topotecan (daily x5) in newly diagnosed patients with metastatic osteosarcoma followed by chemotherapy (ifosfamide, carboplatin, etoposide [ICE], alternating with cisplatin and doxorubicin [CD]). METHODS: Newly diagnosed patients (< or =30 years of age) with extensive metastatic disease (primary and > or =5 pulmonary nodules and/or bone metastases) with normal hepatic, renal, and cardiac function were eligible. Patients were eligible to receive further topotecan after standard chemotherapy if they exhibited a response. Twenty-eight patients were enrolled. Seventeen had metastases to the lung only and 11 had metastases to the bone or multiple sites. Of 28 patients enrolled, 27 could be evaluated for response. A limited dose escalation was incorporated. RESULTS: No responses were seen in the 11 patients treated at 3 mg/m(2)/day. One partial response (PR) and 1 clinical response (CLR) were reported among 15 patients who received topotecan at 3.5 mg/m(2)/day. No dose-limiting toxicity was observed. Principal nondose-limiting toxicities were hematologic and gastrointestinal. The 2- and 5-year event-free survival rates were low, 7% and 4%, respectively, but the 2- and 5-year overall survival rates were 44% and 22%, respectively. CONCLUSIONS: Topotecan at dose of 3.5 mg/m(2)/day can be safely administered upfront to newly diagnosed patients without excessive toxicity. Insufficient activity was seen with topotecan in this schedule to warrant further studies in osteosarcoma. The combination of ICE and CD was tolerable when delivered after initial topotecan therapy.