The menin inhibitor revumenib in KMT2A-rearranged or NPM1-mutant leukaemia.

Targeting critical epigenetic regulators reverses aberrant transcription in cancer, thereby restoring normal tissue function1-3. The interaction of menin with lysine methyltransferase 2A (KMT2A), an epigenetic regulator, is a dependence in acute leukaemia caused by either rearrangement of KMT2A or mutation of the nucleophosmin 1 gene (NPM1)4-6. KMT2A rearrangements occur in up to 10% of acute leukaemias and have an adverse prognosis, whereas NPM1 mutations occur in up to 30%, forming the most common genetic alteration in acute myeloid leukaemia7,8. Here, we describe the results of the first-in-human phase 1 clinical trial investigating revumenib (SNDX-5613), a potent and selective oral inhibitor of the menin-KMT2A interaction, in patients with relapsed or refractory acute leukaemia (ClinicalTrials.gov, NCT04065399). We show that therapy with revumenib was associated with a low frequency of grade 3 or higher treatment-related adverse events and a 30% rate of complete remission or complete remission with partial haematologic recovery (CR/CRh) in the efficacy analysis population. Asymptomatic prolongation of the QT interval on electrocardiography was identified as the only dose-limiting toxicity. Remissions occurred in leukaemias refractory to multiple previous lines of therapy. We demonstrate clearance of residual disease using sensitive clinical assays and identify hallmarks of differentiation into normal haematopoietic cells, including differentiation syndrome. These data establish menin inhibition as a therapeutic strategy for susceptible acute leukaemia subtypes.

Poverty and relapse risk in children with acute lymphoblastic leukemia: a Children's Oncology Group study AALL03N1 report.

The association between individual-level poverty and relapse in children receiving maintenance treatment for acute lymphoblastic leukemia (ALL) remains unclear. In a secondary analysis of COG-AALL03N1, we used data from US Census Bureau to categorize patients living below year-specific federal poverty thresholds, calculated using self-reported annual household income and size of household. Participants with federal poverty thresholds above 120% of their yearly household income were categorized as living in extreme poverty. Hazard of relapse was estimated using multivariable proportional subdistributional hazards regression for patients living in extreme poverty while receiving ALL maintenance therapy after adjusting for relevant predictors. Among 592 patients in this analysis, 12.3% of the patients were living in extreme poverty. After a median follow-up of 7.9 years, the cumulative incidence of relapse at 3 years from study enrollment among those living in extreme poverty was significantly higher (14.3%) than those not living in extreme poverty (7.6%). Multivariable analysis demonstrated that children living in extreme poverty had a 1.95-fold greater hazard of relapse than those not living in extreme poverty; this association was mitigated after the inclusion of race/ethnicity in the model, likely because of collinearity between race/ethnicity and poverty. A greater proportion of children living in extreme poverty were nonadherent to mercaptopurine (57.1% vs 40.9%); however, poor adherence did not completely explain the association between poverty and relapse risk. Future studies need to understand the mechanisms underlying the association between extreme poverty and relapse risk. This trial was registered at www.clinicaltrials.gov as #NCT00268528.

Body mass index during maintenance therapy and relapse risk in children with acute lymphoblastic leukemia: A Children's Oncology Group report.

BACKGROUND: Obesity at diagnosis of childhood acute lymphoblastic leukemia (ALL) is associated with greater risk of relapse; whether this association extends to obesity during maintenance is unstudied. METHODS: This study used data from AALL03N1 to calculate median body mass index (BMI) for 676 children over 6 consecutive months during maintenance therapy; BMI percentile (BMI%ile) were operationalized as normal/underweight (<85%ile), overweight/obese (85%-98%ile), and extreme obesity (≥99%ile). Hazard of relapse was estimated using multivariable proportional subdistributional hazards regression after adjusting for all relevant demographic and clinical predictors. RESULTS: Median age at study enrollment was 6 years and median length of follow-up was 7.9 years. Overall, 43.3% of the cohort was underweight/normal weight, 44.8% was overweight/obese, and 11.8% had extreme obesity. Cumulative incidence of relapse at 4 years from study enrollment was higher among those with extreme obesity (13.6% ± 4.5%) compared to those with underweight/normal weight (9.0% ± 2.1%). Multivariable analysis revealed that children with extreme obesity had a 2.4-fold (95% confidence interval [CI], 1.1-5.0; p = .01) greater hazard of relapse compared to those who were underweight/normal weight. Overweight/obese patients were at comparable risk to those who were underweight/normal weight (hazard ratio, 0.8; 95% CI, 0.4-1.6). Erythrocyte thioguanine nucleotide (TGN) levels were significantly lower among children with extreme obesity compared to those with underweight/normal weight (141.6 vs. 168.8 pmol/8 × 108 erythrocytes; p = .0002), however, the difference in TGN levels did not explain the greater hazard of relapse among those with extreme obesity. CONCLUSIONS: Extreme obesity during maintenance therapy is associated with greater hazard of relapse in children with ALL. Underlying mechanisms of this association needs further investigation. LAY SUMMARY: Findings from this study demonstrate that extreme obesity during maintenance therapy is associated with a greater hazard of relapse among children with acute lymphoblastic leukemia. We show that children with obesity have lower levels of erythrocyte thioguanine nucleotides even after adjusting for adherence to oral chemotherapy. However, these lower levels do not explain the greater hazard of relapse, paving the way for future studies to explore this association.

Choice architecture for young adult blood donor recruitment - a feasibility study.

Blood shortages remain an ongoing challenge, ameliorable by increasing blood donations. Choice architecture is an emerging concept in psychology dealing with the targeted presentation of options to encourage a desired decision. A pilot study was designed to test the feasibility of implementing six choice architecture strategies on a Midwest high-school blood drive. These include framing, conformity, mere measurement, availability heuristic, loss aversion and status quo bias. A pre-post interrupted time-series evaluation was performed to evaluate for an immediate impact on blood donations. All six of the intended choice architecture strategies were successfully implemented. The pre-intervention 5-year average number of blood donations per blood drive was 15 (4.3% of age eligible donors) whereas post intervention, the number of blood donors rose to 25 (7.1% of age eligible donors; p-value = .0013). The application of choice architecture to blood donor recruitment strategies is feasible and has the potential to reduce the burden of blood shortages.

Wearable Monitors Facilitate Exercise in Adult and Pediatric Stem Cell Transplant.

Hematopoietic stem cell transplant (HSCT) is a potentially curative treatment for hematopoietic malignancies, complicated by decreased performance status and quality of life. Exercise therapy improves outcomes in HSCT, but several barriers have prevented exercise from becoming routine clinical practice. Based on existing data that wearable technologies facilitate exercise participation in other sedentary and chronic illness populations, we propose the novel hypothesis that wearable technologies are a valuable tool in transcending barriers and developing exercise therapy programs for HSCT patients.

Reducing sedated lumbar punctures in pediatric patients with acute lymphoblastic leukemia.

BACKGROUND: Sedation for lumbar punctures (LPs) in pediatric acute lymphoblastic leukemia (ALL) patients has been the standard for decades to reduce pain and anxiety. Recent studies on the potential long-term neurocognitive effects of cumulative propofol exposure have raised concerns about this practice. The recent pandemic introduced additional burdens to patients, with the requirement of a negative COVID-19 test prior to each sedated procedure. PROCEDURE: These factors prompted a quality improvement intervention at our institution where we aimed to reduce postinduction sedated LPs by 50%. Our intervention included patient and family education, followed by a simulation of the procedure for selected patients. Those converted to unsedated LPs were queried for their preference. Comparative cost, clinical time, and LP success rates were collected for sedated and unsedated LPs. RESULTS: Following the intervention, the percentage of LPs performed with sedation dropped from 100% to 48%. All LPs were successful using both techniques. Most patients who experienced the unsedated LP technique, and their guardians, strongly preferred this approach. Unsedated LPs significantly reduced clinical time (169 vs. 83 minutes) for families, decreased expenditures ($5736 reduction per procedure), and improved institutional opportunity cost due to a decrease in last-minute cancelations. CONCLUSION: We have shown that it is feasible to significantly reduce the use of sedation for LPs in patients with ALL, which has the potential to improve health and patient experience at a lower cost.

Comparison of self-report and electronic monitoring of 6MP intake in childhood ALL: a Children's Oncology Group study.

Adequate exposure to oral 6-mercaptopurine (6MP) during maintenance therapy for childhood acute lymphoblastic leukemia (ALL) is critical for sustaining durable remissions; accuracy of self-reported 6MP intake is unknown. We aimed to directly compare self-report to electronic monitoring (Medication Event Monitoring System [MEMS]) and identify predictors of overreporting in a cohort of 416 children with ALL in first remission over 4 study months (1344 patient-months for the cohort) during maintenance therapy. Patients were classified as "perfect reporters" (self-report agreed with MEMS), "overreporters" (self-report was higher than MEMS by ≥5 days/month for ≥50% of study months), and "others" (not meeting criteria for perfect reporter or overreporter). Multivariable logistic regression examined sociodemographic and clinical characteristics, 6MP dose intensity, TPMT genotype, thioguanine nucleotide levels, and 6MP nonadherence (MEMS-based adherence <95%) associated with the overreporter phenotype; generalized estimating equations compared 6MP intake by self-report and MEMS. Self-reported 6MP intake exceeded MEMS at least some of the time in 84% of patients. Fifty patients (12%) were classified as perfect reporters, 98 (23.6%) as overreporters, 2 (0.5%) as underreporters, and 266 (63.9%) as others. In multivariable analysis, the following variables were associated with the overreporter phenotype: non-white race: Hispanic, odds ratio (OR), 2.4, P = .02; Asian, OR, 3.1, P = .02; African American, P < .001; paternal education less than college (OR, 1.4, P = .05); and 6MP nonadherence (OR, 9.4, P < .001). Self-report of 6MP intake in childhood ALL overestimates true intake, particularly in nonadherent patients, and should be used with caution.

Barriers to Medication Access in Pediatric Oncology in the United States.

Timely medication access in pediatric oncology is important; yet barriers are poorly described. We surveyed pediatric oncology health care providers at National Cancer Institute Community Oncology Research Program sites on their experience with the impact of drug acquisition difficulties, prior authorization (PA) requests, insurance denials, and patient copays leading to deviations or delays from prescribed treatment for their pediatric/adolescent/young adult patients in calendar year 2016. PA requests, the most frequently cited issue, created a deviation or delay from planned chemotherapy and supportive care treatment in at least 61% of respondents. Half of the respondents believed that PA-induced delays had a negative impact on care. Two-thirds of respondents felt that delays in starting therapy due to barriers in medication access created psychologic or emotional distress for the patient or family. Pediatric cancer patients may be receiving inferior care as a result of barriers to medication access.

Medication prior authorization in pediatric hematology and oncology.

BACKGROUND: Medication prior authorization (PA) is a commonly occurring requirement, particularly for medications used for rare conditions. Based on standard definitions, cancer and many blood disorders affecting children are rare. The study aims were to describe the relative frequency of PA requests and their association with payers and medications in order to identify opportunities to improve system efficiency. PROCEDURE: Requests for medication PA were logged prospectively for patients seen at a single institution over a 7-month period. Period prevalence was used to estimate the relative frequency of PA requests. Descriptive statistics summarized the relationship among payers, medications, and approvals relative to the frequency of PA requests. RESULTS: For the study duration of 150 clinic days, there were 5,583 patient visits. A total of 142 medication PA requests were received resulting in a period prevalence rate of 2.5% patient visits. Of the 137 medication PA requests with available outcome data, 135 (98.5%) were ultimately approved with additional provider efforts. The median clinic staff time spent per request was 46 min with an interquartile range of 25-80 min. There was striking process heterogeneity among different payers. CONCLUSION: Virtually no medication PA request in pediatric hematology and oncology (PHO) leads to alterations in care. Medication utilization management strategies in PHO fail to provide benefits reported in other areas of medicine and have unmeasured negative effects on timeliness of care and parenteral psychological/emotional health. There is opportunity for increasing efficiency through payer and provider collaboration on the creation of prescribing standards for PHO patients.

6MP adherence in a multiracial cohort of children with acute lymphoblastic leukemia: a Children's Oncology Group study.

Durable remissions in children with acute lymphoblastic leukemia (ALL) require a 2-year maintenance phase that includes daily oral 6-mercaptopurine (6MP). Adherence to oral 6MP among Asian-American and African-American children with ALL is unknown. We enrolled 298 children with ALL (71 Asian Americans, 68 African Americans, and 159 non-Hispanic whites) receiving oral 6MP for the maintenance phase. Adherence was measured electronically for 39 803 person-days. Adherence declined from 95.0% (month 1) to 91.8% (month 5, P < .0001). Adherence rates were significantly (P < .0001) lower in Asian Americans (90.0% ± 4.9%) and African Americans (87.1% ± 4.4%), as compared with non-Hispanic whites (95.2% ± 1.3%). Race-specific sociodemographic characteristics helped explain poor adherence (African Americans: low maternal education [less than a college degree: 78.9%, vs at least college degree: 94.6%; P < .0001]; Asian Americans: low-income households [<$50 000: 84.5%, vs ≥$50 000: 96.7%; P = .04]; households without mothers as full-time caregivers [85.6%] vs households with mothers as full-time caregivers [97.2%; P = .05]). Adherence rate below 90% was associated with increased relapse risk (hazard ratio, 3.9; P = .01). Using an adherence rate <90% to define nonadherence, 20.5% of the participants were nonadherers. We identify race-specific determinants of adherence, and define a clinically relevant level of adherence needed to minimize relapse risk in a multiracial cohort of children with ALL. This trial was registered at www.clinicaltrials.gov as #NCT00268528.

Development and Validation of a Ready-to-Talk Measure for Use in Adolescents and Young Adults Living With Advanced Cancer.

BACKGROUND: In the era of evolving and emerging therapies, adolescents and young adults (AYAs) living with advanced cancer experience a high degree of uncertainty, making palliative care and end-of-life (PCEOL) discussions difficult. Clinical conversations determine values/preferences that guide shared decision-making and goals of treatment, including end-of-life care when cancer progresses. Initiating PCEOL conversations is challenging for clinicians. OBJECTIVE: This study describes the development and validation of an instrument that measures AYA readiness to engage in PCEOL clinical conversations. METHODS: A Ready-to-Talk Measure (R-T-M) was developed, guided by the revised conceptual model of readiness across 3 domains (awareness, acceptance, and willingness). Content experts evaluated validity, and 13 AYAs with advanced cancer participated in cognitive interviews. Acceptability (item applicability, clarity, interpretation, sensitivity, missingness) and experiences (benefit, burden) were analyzed. RESULTS: The scale content validity index was ≥0.90 for each domain. Forty-two of the 55 R-T-M items were acceptable without any change. Three items were deleted. Ten items were modified, and 3 were added. Adolescents and young adults wanted more items about friends/siblings and about AYA unique qualities for clinicians to know them better. Adolescents and young adults acknowledged benefit through talking about difficult, relevant topics. CONCLUSION: Ready-to-Talk Measure validity was strengthened by deleting or modifying unclear or misinterpreted items and by adding items. Next steps include psychometric analysis to determine reliability/dimensionality and stakeholder input to make the R-T-M a clinically useful tool. IMPLICATIONS FOR PRACTICE: Ready-to-Talk Measure assessment of readiness to engage in PCEOL conversations while identifying unique preferences of AYAs holds promise for facilitating ongoing discussions.

Adolescents and young adults (AYA) with cancer: the clinical course of COVID-19 infections.

Adolescents and Young Adults (AYAs: 15-39 y) with cancer face unique vulnerabilities, yet remain under-represented on clinical trials, including adult registries of COVID-19 in cancer (AYAs: 8-12%). Thus, we leveraged the Pediatric Oncology COVID-19 Case Report (POCC) to examine the clinical course of COVID-19 among AYAs with cancer. POCC collects de-identified clinical and sociodemographic data regarding 0-39yo with cancer (AYAs = 37%) and COVID-19 from >100 institutions. Between 04/01/2020-11/28/2023, 191 older AYAs [22-39y] and 640 younger AYAs [15-21y] were captured. Older AYAs were less often hospitalized (p < .001), admitted to the intensive care unit (ICU, p = .02), and/or required respiratory support (p = .057). In multivariable analyses, older AYAs faced 80% lower odds of ICU admission but 2.3-times greater odds of changes to cancer-directed therapy. Unvaccinated patients had 5.4-times higher odds of ICU admission. Among AYAs with cancer, the COVID-19 course varies by age. These findings can inform pediatric/adult oncology teams surrounding COVID-19 management and prevention.

Evaluation of the Association Between Congenital Cytomegalovirus Infection and Pediatric Acute Lymphoblastic Leukemia.

Importance: Acute lymphoblastic leukemia (ALL) is the most common form of pediatric cancer, and a leading cause of death in children. Understanding the causes of pediatric ALL is necessary to enable early detection and prevention; congenital cytomegalovirus (cCMV) has recently been identified as a potential moderate-to-strong factor associated with risk for ALL. Objective: To compare the prevalence of cCMV infection between ALL cases and matched controls. Design, Setting, and Participants: In this population-based case-control study of ALL cases and matched controls, cases consisted of children aged 0 to 14 years between 1987 and 2014 with an ALL diagnosis identified through the Michigan Cancer Surveillance Program and born in Michigan on or after October 1, 1987. Cancer-free controls were identified by the Michigan BioTrust for Health and matched on age, sex, and mother's race and ethnicity. Data were analyzed from November to May 2022. Exposures: cCMV infection measured by quantitative polymerase chain reaction in newborn dried blood spots. Main Outcomes and Measures: ALL diagnosed in children aged 0 to 14 years. Results: A total of 1189 ALL cases and 4756 matched controls were included in the study. Bloodspots were collected from participants at birth, and 3425 (57.6%) participants were male. cCMV was detected in 6 ALL cases (0.5%) and 21 controls (0.4%). There was no difference in the odds of cCMV infection comparing ALL cases with controls (odds ratio, 1.30; 95% CI, 0.52-3.24). Immunophenotype was available for 536 cases (45.1%) and cytogenetic data for 127 (27%). When stratified by subtype characteristics, hyperdiploid ALL (74 cases) was associated with 6.26 times greater odds of cCMV infection compared with unmatched controls (95% CI, 1.44-27.19). Conclusions and Relevance: In this case-control study of cCMV and pediatric ALL, cCMV was associated with increased risk of hyperdiploid ALL. These findings encourage continued research.

Intronic Germline DICER1 Variants in Patients With Sertoli-Leydig Cell Tumor.

Germline pathogenic loss-of-function (pLOF) variants in DICER1 are associated with a predisposition for a variety of solid neoplasms, including pleuropulmonary blastoma and Sertoli-Leydig cell tumor (SLCT). The most common DICER1 pLOF variants include small insertions or deletions leading to frameshifts, and base substitutions leading to nonsense codons or altered splice sites. Larger deletions and pathogenic missense variants occur less frequently. Identifying these variants can trigger surveillance algorithms with potential for early detection of DICER1-related cancers and cascade testing of family members. However, some patients with DICER1-associated tumors have no pLOF variants detected by germline or tumor testing. Here, we present two patients with SLCT whose tumor sequencing showed only a somatic missense DICER1 RNase IIIb variant. Conventional exon-directed germline sequencing revealed no pLOF variants. Using a custom capture panel, we discovered novel intronic variants, ENST00000343455.7: c.1752+213A>G and c.1509+16A>G, that appear to interfere with normal splicing. We suggest that when no DICER1 pLOF variants or large deletions are discovered in exonic regions despite strong clinical suspicion, intron sequencing and splicing analysis should be performed.

Barriers to Pediatric Oncologist Enrollment of Adolescents and Young Adults on a Cross-Network National Clinical Trials Network Supportive Care Cancer Clinical Trial.

Few studies have explored interventions to improve adolescent and young adult (AYA) cancer care delivery. While many AYAs receive cancer care at NCI Community Oncology Research Program (NCORP) sites, few enroll on clinical trials. Barriers and facilitators to pediatric oncologist activation of and enrollment on an AYA cross-network National Clinical Trials Network (NCTN) supportive care trial were assessed using a survey that was administered to 162 stakeholders representing all 47 children's oncology group (COG) institutions affiliated to an NCORP. Fifty-eight stakeholders participated representing 62% of all sites surveyed. Approximately half of participants (45%) were unaware of the trial. Seven sites had the study open and one enrolled a patient. Reasons for not opening and enrolling on the trial included limited research staff and resources, low anticipated accrual, and lower prioritization of the trial. Enrollment facilitators included having a local "AYA champion," improving communication between pediatric and medical oncology, and having site education on available AYA trials. Interventions focused on increasing site and provider awareness of AYA trials and decreasing local barriers to AYA enrollment are needed.

SARS-CoV-2 in Childhood Cancer in 2020: A Disease of Disparities.

PURPOSE: The Pediatric Oncology COVID-19 Case Report registry supplies pediatric oncologists with data surrounding the clinical course and outcomes in children with cancer and SARS-CoV-2. METHODS: This observational study captured clinical and sociodemographic characteristics for children (≤ 21 years) receiving cancer therapy and infected with SARS-CoV-2 from the pandemic onset through February 19, 2021. The demographic and clinical characteristics of the cohort were compared with population-level pediatric oncology data (SEER). Multivariable binomial regression models evaluated patient characteristics associated with hospitalization, intensive care unit (ICU) admission, and changes in cancer therapy. RESULTS: Ninety-four institutions contributed details on 917 children with cancer and SARS-CoV-2. Median age at SARS-CoV-2 infection was 11 years (range, 0-21 years). Compared with SEER, there was an over-representation of Hispanics (43.6% v 29.7%, P < .01), publicly insured (59.3% v 33.5%, P < .01), and patients with hematologic malignancies (65.8% v 38.3%, P < .01) in our cohort. The majority (64.1%) were symptomatic; 31.2% were hospitalized, 10.9% required respiratory support, 9.2% were admitted to the ICU, and 1.6% died because of SARS-CoV-2. Cancer therapy was modified in 44.9%. Hispanic ethnicity was associated with changes in cancer-directed therapy (adjusted risk ratio [aRR] = 1.3; 95% CI, 1.1 to 1.6]). Presence of comorbidities was associated with hospitalization (aRR = 1.3; 95% CI, 1.1 to 1.6) and ICU admission (aRR = 2.3; 95% CI, 1.5 to 3.6). Hematologic malignancies were associated with hospitalization (aRR = 1.6; 95% CI, 1.3 to 2.1). CONCLUSION: These findings provide critical information for decision making among pediatric oncologists, including inpatient versus outpatient management, cancer therapy modifications, consideration of monoclonal antibody therapy, and counseling families on infection risks in the setting of the SARS-CoV-2 pandemic. The over-representation of Hispanic and publicly insured patients in this national cohort suggests disparities that require attention.

Comparing pediatric deaths with and without hospice support.

BACKGROUND: Although pediatric hospice care is commonly accepted as a beneficial intervention, the incremental advantage over end-of-life care delivered without engaging hospice remains unknown. The primary objective of this study was to describe differences in pediatric end-of-life care when delivered with and without hospice support, as perceived by the medical provider. PROCEDURE: A retrospective survey of medical providers was conducted in 2005 over a 2-month period at a single institution, the Helen DeVos Children's Hospital (HDVCH). Medical providers with self-determined experience in pediatric end-of-life care were asked to separately provide positive and negative comments about their experience with hospice. Additionally they were asked to describe differences between children under their supervision who died with and without hospice care. Medical provider comments and comparisons of experiences in caring for children dying with and without hospice involvement are described. RESULTS: Out of 157 responders, 43 reported positive comments about the hospice intervention. Non-medical support and location of death were the most frequently cited benefits. Nineteen responders provided negative comments about hospice; all involving feelings of lost hope, intrusion, or distrust. When asked to directly compare deaths with and without hospice support, 44 of 51 (86%) responders favored hospice. The most cited reason for preferring hospice involvement was better provision of non-medical services. CONCLUSIONS: The majority of pediatric providers in this survey observed an advantage to utilizing hospice care for dying children as compared to providing end-of-life care without hospice involvement.

Understanding the Barriers to Pediatric Oncologist Engagement and Accrual to Clinical Trials in National Cancer Institute-Designated Community Oncology Research Programs.

PURPOSE: Clinical trial participation leads to progress in cancer care. Principal investigators (PIs) and clinical research associates (CRAs) play key roles in the provision and maintenance of clinical trial portfolios at their sites. Previous studies have evaluated the educational and resource needs of adult oncology providers, but nothing to date has focused on providers of pediatric oncology care. We aimed to identify the educational needs and clinical trial participation barriers at National Cancer Institute Community Oncology Research Program (NCORP) Children's Oncology Group (COG) sites to improve the quality of site investigator engagement. METHODS: Quality improvement surveys of pediatric clinical research staff at NCORP sites were performed. The first was a web-based inquiry of NCORP COG PIs and lead CRAs to assess their general understanding of NCORP organizational structure and needs. The second survey of COG PIs was conducted by one-on-one telephone interviews aimed at identifying specific barriers to physician engagement and patient enrollment in clinical trial research. RESULTS: The majority of NCORP COG PIs and CRAs (63%) reported an incomplete understanding of NCORP structure, with approximately half expressing interest in developing stronger collaborations and engagement. Most NCORP COG PIs reported at least one shared barrier to clinical trial enrollment (78%), with inadequate protected time and research support (39% each) being the most frequently cited barriers. CONCLUSIONS: Contributions to pediatric cancer clinical research at COG NCORP sites could be enhanced through improved education, resources, and time allocation.

Therapeutic strategies for targeting mononuclear phagocytes in cancer.

The initiation and progression of cancer is dependent on factors both intrinsic and extrinsic to the malignant cells. Stromal, vascular endothelial, and inflammatory cells are the principal normal populations that support tumors by supplying factors and nutrients. The mononuclear phagocyte lineage, which includes monocytes, macrophages, and dendritic cells is of particular clinical interest because lineage members can enhance tumor angiogenesis and metastasis, or alternately contribute to tumor destruction. Thus therapies that regulate these cells represent an innovative approach for improving patient survival in childhood cancer.

New roles for mononuclear phagocytes in cancer biology.

The primary focus in the pathogenesis and treatment of human malignancies has been the tumor cell. However, the biologic properties of a malignancy are not all intrinsically determined. Interactions between heterogeneous cell populations influence the growth and survival of both normal and malignant cells. Studies defining the origin of endothelial cells involved in tumor angiogenesis first demonstrated the contributions of normal cellular environment. Recently, the mononuclear phagocyte lineage has been found to have biologically and clinically significant tumor enhancing and tumor suppressive effects. This article reviews the multiple roles of mononuclear phagocytes in cancer biology. A companion manuscript (J Pediatr Hematol Oncol. 2008, in press) describes the targeting of these cells for therapeutic benefit. Incorporating these strategies into future childhood cancer protocols could be an innovative approach for improving patient outcome.