Molecular diagnosis and risk-adjusted therapy in pediatric hematologic malignancies: a primer for pediatricians

Comprehensive Prognostication in Critically Ill Pediatric Hematopoietic Cell Transplant Patients: Results from Merging the Center for International Blood and Marrow Transplant Research (CIBMTR) and Virtual Pediatric Systems (VPS) Registries

Critically ill pediatric allogeneic hematopoietic cell transplant (HCT) patients may benefit from early and aggressive interventions aimed at reversing the progression of multiorgan dysfunction. Therefore, we evaluated 25 early risk factors for pediatric intensive care unit (PICU) mortality to improve mortality prognostication. We merged the Virtual Pediatric Systems and Center for International Blood and Marrow Transplant Research databases and analyzed 936 critically ill patients ≤21 years of age who had undergone allogeneic HCT and subsequently required PICU admission between January 1, 2009, and December 31, 2014. Of 1532 PICU admissions, the overall PICU mortality rate was 17.4% (95% confidence interval [CI], 15.6% to 19.4%) but was significantly higher for patients requiring mechanical ventilation (44.0%), renal replacement therapy (56.1%), or extracorporeal life support (77.8%). Mortality estimates increased significantly the longer that patients remained in the PICU. Of 25 HCT- and PICU-specific characteristics available at or near the time of PICU admission, moderate/severe pre-HCT renal injury, pre-HCT recipient cytomegalovirus seropositivity, <100-day interval between HCT and PICU admission, HCT for underlying acute myeloid leukemia, and greater admission organ dysfunction as approximated by the Pediatric Risk of Mortality 3 score were each independently associated with PICU mortality. A multivariable model using these components identified that patients in the top quartile of risk had 3 times greater mortality than other patients (35.1% versus 11.5%, P < .001, classification accuracy 75.2%; 95% CI, 73.0% to 77.4%). These data improve our working knowledge of the factors influencing the progression of critical illness in pediatric allogeneic HCT patients. Future investigation aimed at mitigating the effect of these risk factors is warranted.

Hematological malignancies and molecular targeting therapy

Recent genetic analysis using next-generation sequencing (NGS) vastly improved the understanding of molecular mechanism of hematological malignancies. Many molecular targeting drugs have since been used in the clinic, which is timely as clinical outcomes using conventional chemotherapy and hematopoietic stem cell transplantation (HSCT) reached a plateau. The first memorable success in this field was imatinib, a first-generation tyrosine kinase inhibitor (TKI), which has been applied in chronic myeloid leukemia (CML) since 2001. Imatinib drastically changed CML treatment and many CML patients no longer require HSCT. Recently, the second generation TKIs, dasatinib, nilotinib, and ponatinib, have also been available for CML patients. Acute lymphoblastic leukemia (ALL) is sub-categorized based on cytogenetic or molecular genetic abnormalities. Chemotherapy and HSCT combined with TKI improved the event-free survival rate from 20% to 80% in Philadelphia (Ph) chromosome-positive ALL. Reportedly, another Ph-like ALL subgroup with poor prognosis can also be treated by TKIs; additionally, cell therapies that include bispecific T-cell engagers or chimeric antigen receptor (CAR)-T therapy are emerging. Acute myeloid leukemia (AML) is a heterogenous disease and FMS-like related tyrosine kinase-3 (FLT3)-internal tandem duplication, is the most robust marker for poor prognosis. Several first-generation TKIs have been studied for clinical use. Notably, chemotherapy plus midostaurin improved survival compared with chemotherapy alone. Therefore, midostaurin was approved to treat adult AML patients with FLT3-ITD in 2017. Gemtuzumab ozogamicin, a selective anti-CD33 antibody-calicheamicin conjugate, is approved for clinical practice. Many molecular targeting agents are now being used for hematological malignancies.

Global characteristics of childhood acute promyelocytic leukemia

Acute promyelocytic leukemia (APL) comprises approximately 5-10% of childhood acute myeloid leukemia (AML) cases in the US. While variation in this percentage among other populations was noted previously, global patterns of childhood APL have not been thoroughly characterized. In this comprehensive review of childhood APL, we examined its geographic pattern and the potential contribution of environmental factors to observed variation. In 142 studies (spanning >60 countries) identified, variation was apparent-de novo APL represented from 2% (Switzerland) to >50% (Nicaragua) of childhood AML in different geographic regions. Because a limited number of previous studies addressed specific environmental exposures that potentially underlie childhood APL development, we gathered 28 childhood cases of therapy-related APL, which exemplified associations between prior exposures to chemotherapeutic drugs/radiation and APL diagnosis. Future population-based studies examining childhood APL patterns and the potential association with specific environmental exposures and other risk factors are needed.

Pediatric cancer type predicts infection rate, need for critical care intervention, and mortality in the pediatric intensive care unit

PURPOSE

Up to 38 % of children with cancer require pediatric intensive care unit (PICU) admission within 3 years of diagnosis, with reported PICU mortality of 13-27 % far exceeding that of the general PICU population. PICU outcomes data for individual cancer types are lacking and may help identify patients at risk for poor clinical outcomes.

METHODS

We performed a retrospective multicenter analysis of 10,365 PICU admissions of cancer patients no greater than 21 years old among 112 PICUs between 1 January 2009 and 30 June 2012. We evaluated the effect of cancer type, age, gender, genetic syndrome, stem cell transplantation, PRISM3 score, infections, and critical care interventions on PICU mortality.

RESULTS

After excluding scheduled perioperative admissions, cancer patients represented 4.2 % of all PICU admissions (10,365/246,346), had overall mortality of 6.8 % (708/10,365) vs. 2.4 % (5,485/230,548) in the general PICU population (RR = 2.9, 95 % CI 2.7-3.1, p < 0.001), and accounted for 11.4 % of all PICU deaths (708/6,215). Hematologic cancer patients had greater median PRISM3 score (8 vs 2, p < 0.001), rates of sepsis (27 vs 9 %, RR = 2.9, 95 % CI 2.6-3.1, p < 0.001), and mortality (9.6 vs 4.5 %, RR = 2.1, 95 % CI 1.8-2.5, p < 0.001) compared to solid cancer patients. Among hematologic cancer patients, stem cell transplantation, diagnosis of acute myeloid leukemia, PRISM3 score, and infection were all independently associated with PICU mortality.

CONCLUSIONS

Children with cancer account for 4.2 % of PICU admissions and 11.4 % of PICU deaths. Hematologic cancer patients have significantly higher admission illness severity, rates of infections, and PICU mortality than solid cancer patients. These data may be useful in risk stratification for closer monitoring and patient counseling.

Malignancies in children and young adults on etanercept: summary of cases from clinical trials and post marketing reports

BACKGROUND

Malignancy risk may be increased in chronic inflammatory conditions that are mediated by tumor necrosis factor (TNF), such as juvenile idiopathic arthritis (JIA), but the role of TNF in human cancer biology is unclear. In response to a 2011 United States Food & Drug Administration requirement of TNF blocker manufacturers, we evaluated reporting rates of all malignancies in patients =30 years old who received the TNF blocker etanercept.

METHODS

All malignancies in etanercept-exposed patients aged =30 years from the Amgen clinical trial database (CTD) and postmarketing global safety database (PMD) were reviewed. PMD reporting rates were generated using exposure information based on commercial sources. Age-specific incidence rates of malignancy for the general US population were generated from the Surveillance Epidemiology and End Results (SEER) database v7.0.9.

RESULTS

There were 2 malignancies in the CTD: 1 each in etanercept and placebo/comparator arms (both in patients 18-30 years old). Postmarketing etanercept exposure was 231,404 patient-years (62,379 patient-years in patients 0-17 years; 168,485 patient-years in patients 18-30 years). Reporting rates of malignancy per 100,000 patient-years in the PMD and incidence rates in SEER were 32.0 and 15.9, respectively, for patients 0-17 years and 46.9 and 42.1 for patients 18-30 years old. Reporting rates were higher than SEER incidence rates for Hodgkin lymphoma in the 0-17 years age group. PMD reporting rates per 100,000 patient-years and SEER incidence rates per 100,000 person-years for Hodgkin lymphoma were 9.54 and 0.9, respectively, for patients 0-17 years and 1.8 and 4.2 for patients 18-30 years old. There were =5 cases of leukemia, lymphoma, melanoma, thyroid, and cervical cancers. Leukemia, non-Hodgkin lymphoma, melanoma, thyroid cancer, and cervical cancer rates were similar in the PMD and SEER.

CONCLUSIONS

Overall PMD malignancy reporting rates in etanercept-treated patients 0-17 years appeared higher than incidence rates in SEER, attributable to rates of Hodgkin lymphoma. Comparison to patients with similar burden of disease cannot be made; JIA, particularly very active disease, may be a risk factor for lymphoma. No increased malignancy reporting rate in the PMD relative to SEER was observed in the young-adult age group.

Pediatric oncology for the general pediatrician: introduction to the Educational series

Since its establishment as a pediatric subspecialty oncology has become the near exclusive domain of specialized tertiary centers. This has greatly aided progress in the field with formation of exemplary and highly focused international consortia that have continued to streamline clinical research efforts. Recently, the rate of progress in terms of further improvements in overall outcome has paradoxically slowed. Novel strategies are therefore needed to assure continued advances. On the one hand, international and global consortia of subspecialists will continue to focus on the development of much needed improved therapies for those disease groups that have not yet seen their prognosis brighten, and on the other hand, there is a trend to invest in the development of joint-care initiatives that assure cost-effective access to standard therapy for all. This will require closer involvement of the general pediatrician in certain aspects of cancer care in its broadest sense. We hope the upcoming series will aid this process by highlighting selected topics in pediatric oncology that are likely to gain even more relevance for the general pediatrician in the years to come. They include: screening strategies for cancer predisposition syndromes; molecular diagnosis and risk-adjustment of therapy for acute leukemia in childhood; an overview of new agents in clinical development; and the impact of cancer treatment on fertility and available preservation options.