Racial and ethnic differences in survival of children with acute lymphoblastic leukemia

Differential inequality trends over time in survival among U.S. children with acute lymphoblastic leukemia by race/ethnicity, age at diagnosis, and sex

BACKGROUND

It is unclear how inequalities in survival among children with acute lymphoblastic leukemia (ALL) have changed over time in different race/ethnicity groups.

METHODS

Children diagnosed with a first primary malignant ALL at ages 0 to 19 years in 1975-2010 in the nine Surveillance, Epidemiology, and End Results cancer registries were included. Cumulative ALL mortalities were compared, and multivariable Cox regression analyses were applied to estimate ALL mortality HRs associated with race/ethnicity, age at diagnosis, and sex, adjusting for each other, within each diagnosis period (1975-1983, 1984-1991, 1992-1999, and 2000-2010).

RESULTS

Compared with non-Hispanic-whites (NH-whites), the HR in non-Hispanic-blacks (NH-blacks) dropped to 1.21 [95% confidence interval (CI), 0.74-1.96] in 2000-2010 from the largest inequality in 1984-1991 (HR, 2.09; 95% CI, 1.57-2.79); the HR in Hispanics increased, however, from 1.28 (95% CI, 0.98-1.66) in 1975-1983 to 1.95 (95% CI, 1.48-2.58) in 2000-2010. Asian/Pacific Islanders (API) and American Indian/Alaska Natives (AIAN) had HRs of 1.39 (95% CI, 0.92-2.11) and 2.31 (95% CI, 1.13-4.74), respectively, in 2000-2010 with nonstatistically significant increases over time. In 2000-2010, compared with NH-white counterparts, NH-blacks and APIs diagnosed at 1-9 years, Hispanics diagnosed at 1-9 and 10-19 years, and AIANs diagnosed at 10-19 years all had about twice the ALL mortality hazard rates; inequality was observed among API boys (HR, 1.61; 95% CI, 1.00-2.60) but not API girls.

CONCLUSIONS

Survival inequalities changed differently across subgroups of children with ALL.

IMPACT

Underlying causes of the differential trends need to be examined, such that targeted interventions can be developed to reduce inequalities.

Participation in pediatric oncology research protocols: Racial/ethnic, language and age-based disparities

BACKGROUND

Survival rates in pediatric oncology have improved dramatically, in part due to high patient participation in clinical trials. Although racial/ethnic inequalities in clinical trial participation have been reported in adults, pediatric data and studies comparing participation rates by socio-demographic characteristics are scarce. The goal of this study was to assess differences in research protocol participation for childhood cancer by age, sex, race/ethnicity, parental language, cancer type, and insurance status.

PROCEDURE

Data on enrollment in any protocol, biospecimen, or therapeutic protocols were collected and analyzed for newly diagnosed pediatric patients with cancer from 2008-2012 at Rady Children's Hospital.

RESULTS

Among the 353 patients included in the analysis, 304 (86.1%) were enrolled in any protocol. Enrollment in biospecimen and therapeutic protocols was 84.2% (261/310) and 81.1% (206/254), respectively. Logistic regression analyzes revealed significant enrollment underrepresentation in any protocol for Hispanics compared to Non-Hispanic whites (81% vs. 91%; Odds Ratio [OR], 0.43; 95% Confidence Interval [CI], 0.21-0.90; P = 0.021) and among children of Spanish-speaking vs. English-speaking parents (78% vs. 89%; OR, 0.45; 95%CI, 0.23-0.87; P = 0.016). Compared to patients aged 0-4 years, significant underrepresentation was also found among patients 15-21 years old (92% vs.72%; OR, 0.21; 95% CI, 0.09-0.48; P < 0.001). Similar trends were observed when analyzing enrollment in biospecimen and therapeutic protocols separately.

CONCLUSIONS

There was significant underrepresentation in protocol participation for Hispanics, children of Spanish-speaking parents, and patients ages 15-21. Research is needed to understand barriers to research participation among these groups underrepresented in pediatric oncology clinical trials.

Association between CEBPE Variant and Childhood Acute Leukemia Risk: Evidence from a Meta-Analysis of 22 Studies

The CCAAT/enhancer binding proteins (CEBPs) have been involved in the etiology of acute leukemia (AL) and investigated in numerous genetic association studies, however, the results were inconclusive. The current meta-analysis was conducted to clarify the effect of CEBPE rs2239633 variant on childhood AL risk. Electronic literature search was performed on August 15, 2014, from databases of Medline, PubMed, Embase, and Web of Science. A total of 22 case-control studies were eligible for the pooled analysis. The results demonstrated that rs2239633 A allele was significantly associated with a decreased risk of childhood AL (A vs G: OR=0.87, 95%CI = 0.80, 0.94, p<0.001), especially in B-cell ALL subgroup (A vs G: OR = 0.79, 95%CI = 0.74, 0.83, p<0.001), but not among T-cell ALL or AML subgroups. In the stratified analysis by ethnicity, the association was observed in Europeans (A vs G: OR = 0.80, 95%CI = 0.76, 0.84, p<0.001) but not in Asian and mixed populations. Moreover, the results of sensitivity and cumulative meta-analysis indicated the robustness of our results. Also, Begg’s and Egger’s tests did not indicate any evidence of obvious asymmetry. In summary, our study provided evidence that CEBPE rs2239633 variant is associated with decreased risk of childhood B-cell ALL in Europeans.

Socioeconomic disparities in survival from childhood leukemia in the United States and globally: a meta-analysis

BACKGROUND

Despite advancements in the treatment of childhood leukemia, socioeconomic status (SES) may potentially affect disease prognosis. This study aims to evaluate whether SES is associated with survival from childhood leukemia.

METHODS

The US National Cancer Institute Surveillance, Epidemiology and End Results Program (SEER) 1973-2010 data were analyzed; thereafter, results were meta-analyzed along with those from survival (cohort) studies examining the association between SES indices and survival from childhood leukemia (end-of-search date: 31 March 2014). Random-effects models were used to calculate pooled effect estimates (relative risks, RRs); meta-regression was also used.

RESULTS

We included 29 studies yielding 28 804 acute lymphoblastic leukemia (ALL), 3208 acute myeloblastic leukemia (AML) and 27 650 'any' leukemia (denoting joint reporting of all subtypes) cases. According to individual-level composite SES indices, children from low SES suffered from nearly twofold higher death rates from ALL (pooled RR: 1.83, 95% confidence interval 1.00-3.34, based on four study arms); likewise, death RRs derived from an array of lower area-level SES indices ranged between 1.17 and 1.33 (based on 11 study arms). Importantly, the survival gap between higher and lower SES seemed wider in the United States, with considerably (by 20%-82%) increased RRs for death from ALL in lower SES. Regarding AML, poorer survival was evident only when area-level SES indices were used. Lastly, remoteness indices were not associated with survival from childhood leukemia.

CONCLUSION

Children with lower SES suffering childhood leukemia do not seem to equally enjoy the impressive recent survival gains. Special health policy strategies and increased awareness of health providers might minimize the effects of socioeconomic disparities.

Health disparities are important determinants of outcome for children with solid tumor malignancies

PURPOSE

The purpose of this study was to identify health disparities in children with non-CNS solid tumor malignancies and examine their impact on disease presentation and outcome.

METHODS

We examined the records of all children (age≤18years) diagnosed with a non-CNS solid tumor malignancy and enrolled in the Texas Cancer Registry between 1995 and 2009 (n=4603). The primary outcome measures were disease stage and overall survival (OS). Covariates included gender, age, race/ethnicity, year of diagnosis, socioeconomic status (SES), and driving distance to the nearest pediatric cancer treatment facility. Statistical analyses included life table methods, logistic, and Cox regression. Statistical significance was defined as p<0.05.

RESULTS

Children with advanced-stage disease were more likely to be male, <10years old, and Hispanic or non-Hispanic Blacks (all p<0.05). Distance to treatment and SES did not impact stage of disease at presentation. However, Hispanic and non-Hispanic Blacks and patients in the lowest SES quartile had the worst 1- and 5-year survival (all p<0.05). The adjusted OS differed by age, race, and stage, but not SES or distance to the nearest treatment facility.

CONCLUSIONS

Race/ethnicity plays an important role in survival for children with non-CNS solid tumor malignancies. Future work should better define these differences to establish mechanisms to decrease their impact.

Advanced stage anaplastic large cell lymphoma in children and adolescents: results of ANHL0131, a randomized phase III trial of APO versus a modified regimen with vinblastine: a report from the children's oncology group

BACKGROUND

Optimal therapy for children and adolescents with advanced stage anaplastic large cell lymphoma (ALCL) is unknown. ANHL0131 examined whether a maintenance regimen including vinblastine compared to the standard APO (doxorubicin, prednisone, vincristine, methotrexate, 6-mercaptopurine) regimen would result in superior event-free survival.

PROCEDURE

One hundred and twenty five eligible patients were enrolled. Induction was identical for both arms. Post induction patients were randomized to receive APO with vincristine every 3 weeks or a regimen that substituted vincristine with weekly vinblastine (APV).

RESULTS

There was no difference between the patients randomized to the APO versus APV arms in either event free survival (EFS) or overall survival (OS) (three year EFS 74% vs. 79%, P = 0.68 and three years OS of 84% vs. 86%, P = 0.87, respectively). Patients in the APV arm required dose reduction secondary to myelosuppression and had a higher incidence of neutropenia as well as infection with neutropenia compared to those in the APO arm (P < 0.001, P = 0.019, respectively).

CONCLUSIONS

Treatment with weekly vinblastine instead of every three week vincristine as part of multi-agent maintenance therapy did not result in improvement in EFS or OS. Weekly vinblastine was associated with increased toxicity. (ClinicalTrials.gov Identifier NCT00059839).

Obesity is associated with residual leukemia following induction therapy for childhood B-precursor acute lymphoblastic leukemia

Obesity is associated with poorer event-free survival (EFS) in pediatric acute lymphoblastic leukemia (ALL). Persistent minimal residual disease (MRD) in the bone marrow as measured by multidimensional flow cytometry (MDF) is a key early prognostic indicator and is strongly associated with EFS. We therefore hypothesized that obesity during induction would be associated with positive end-of-induction MRD (≥0.01%). We analyzed MDF of end-induction bone marrow samples from a historical cohort of 198 children newly diagnosed with B-precursor ALL (BP-ALL) and treated with Children's Oncology Group induction regimens. We assessed the influence of body mass index on risk for positive end-induction MRD in the bone marrow. In our cohort of BP-ALL, 30 children (15.2%) were overweight and 41 (20.7%) were obese at diagnosis. Independent of established predictors of treatment response, obesity during induction was associated with significantly greater risk for persistent MRD (odds ratio, 2.57; 95% confidence interval, 1.19 to 5.54; P = .016). Obesity and overweight were associated with poorer EFS irrespective of end-induction MRD (P = .012). Obese children with newly diagnosed BP-ALL are at increased risk for positive end-induction MRD and poorer EFS.

Cancer-related follow-up care among Hispanic and non-Hispanic childhood cancer survivors: The Project Forward study

BACKGROUND

Follow-up care is critical for childhood cancer survivors (CCS), who are at high risk for comorbidities and late effects of cancer treatments. Understanding the factors associated with maintaining follow-up care is needed, especially for Hispanic CCS, who have been under-represented in previous studies.

METHODS

Risk factors and protective factors for receiving cancer-related follow-up care were examined among 193 Los Angeles County CCS diagnosed between 2000 and 2007 (54% Hispanic; mean ± standard deviation age, 19.9 ± 2.8 years; age at diagnosis, 12.1 ± 3.0 years; time since diagnosis, 7.8 ± 2.0 years). Self-report surveys were used to assess follow-up care, insurance status, demographics, clinical factors, and psychosocial risk (eg, depression) and protective (eg, self-efficacy [SE]) factors. Multivariable logistic regression was used to identify factors associated with the previous receipt of cancer-related follow-up care (in prior 2 years) and the intent to seek future cancer-related follow-up care.

RESULTS

Seventy-three percent of CCS reported a cancer follow-up visit in the previous 2 years, which was positively associated (P < .05) with having health insurance, white ethnicity (vs Hispanic), younger age, and greater treatment intensity. Sixty-nine percent reported an intent to receive follow-up care in the next 2 years, which was positively associated (P < .05) with having health insurance and greater SE.

CONCLUSIONS

Hispanics and older CCS were more likely to lack previous follow-up care. Because health insurance was strongly associated with both previous follow-up care and the intent to seek care, the current results indicate that recent changes in health coverage may improve follow-up among CCS. Interventions targeting improved SE may help increase intent to receive follow-up care for this population.

Characterization of pediatric acute lymphoblastic leukemia survival patterns by age at diagnosis

Age at diagnosis is a key prognostic factor in pediatric acute lymphoblastic leukemia (ALL) survivorship. However, literature providing adequate assessment of the survival variability by age at diagnosis is scarce. The aim of this study is to assess the impact of this prognostic factor in pediatric ALL survival. We estimated incidence rate of mortality, 5-year survival rate, Kaplan-Meier survival function, and hazard ratio using the Surveillance Epidemiology and End Results (SEER) data during 1973–2009. There was significant variability in pediatric ALL survival by age at diagnosis. Survival peaked among children diagnosed at 1–4 years and steadily declined among those diagnosed at older ages. Infants (<1 year) had the lowest survivorship. In a multivariable Cox proportional hazard model stratified by year of diagnosis, those diagnosed in age groups 1–4, 5–9, 10–14, and 15–19 years were 82%, 75%, 57%, and 32% less likely to die compared to children diagnosed in infancy, respectively. Age at diagnosis remained to be a crucial determinant of the survival variability of pediatric ALL patients, after adjusting for sex, race, radiation therapy, primary tumor sites, immunophenotype, and year of diagnosis. Further research is warranted to disentangle the effects of age-dependent biological and environmental processes on this association.

Cultural Influences in Pediatric Cancer

Objective: To review the literature on cultural factors influencing clinical care and family management of pediatric cancer. Methods: A literature review including 72 articles related to cultural issues in pediatric cancer was conducted. Information was organized around several clinically driven themes. Results: Cultural factors influenced many aspects of the cancer experience including illness representations, reaction to diagnosis, illness disclosure patterns, complementary and alternative medicine use, management of medical procedures, coping strategies, and end of life issues. Conclusion: Increased awareness of cultural factors is needed to improve clinical care and reduce health disparities. Specific strategies to approach cultural differences are provided to enhance patient and family care from diagnosis to cure/end of life.

Genomic ancestry and somatic alterations correlate with age at diagnosis in Hispanic children with B-cell acute lymphoblastic leukemia

Hispanic children have a higher incidence of acute lymphoblastic leukemia (ALL) than non-Hispanic whites but tend to be diagnosed at older ages. In genome-wide association studies, Native American ancestry and polymorphisms in six genes have been associated with ALL risk. In multivariable regression models, we investigated whether genomic ancestry, inherited risk SNPs, or acquired somatic alterations were associated with differences in age at diagnosis in Hispanic children with B-cell ALL. Genome-wide array data were used to estimate each participant's percent membership in the three Hispanic ancestral populations: Native American, African, and European. Each 20% increase in European ancestry was associated with a six month younger age at diagnosis (95% CI = 0.36-11.6 months, P = 0.037). Correspondingly, each 20% increase in Native American ancestry was associated with a six-month older age at diagnosis (P = 0.037). Both the TEL-AML1 translocation and high-hyperdiploidy were associated with younger age at diagnosis (24.4 months, P = 2.0 x 10(-4) and 12.4 months, P = 0.011, respectively), while CDKN2A and IKZF1 deletions were associated with older age at diagnosis (19.7 months, P = 7.0 x 10(-4) and 18.1 months, P = 0.012, respectively). No associations with age at diagnosis were observed for RAS mutation, PAX5 deletion or for known heritable risk alleles in IKZF1, CDKN2A, PIP4K2A, GATA3, ARID5B, or CEBPE. Because younger age at diagnosis is associated with improved treatment outcomes for children with ALL, the effect of European ancestry on ALL survival may be mediated by its effect on age at diagnosis, or by proxy, its association with more treatable molecular subtypes of ALL.

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.

A meta-analysis of the association between NQO1 C609T variation and acute myeloid leukemia risk

Quinone oxidoreductase (NQO1) C609T polymorphisms have been implicated in acute myeloblastic leukemia (AML) risk, but previously published studies are inconsistent and recent meta-analyses have not been adequate. To derive a more precise estimation of the relationship, a meta-analysis was performed. Medline, PubMed, Embase, and Web of Science were searched. The quality of studies was evaluated by using the Newcastle-Ottawa Scale (NOS). Crude ORs with 95% CIs were used to assess the strength of association between the NQO1 C609T polymorphisms and AML risk. A total of 14 studies including 2,245 cases and 3,310 controls were involved in this meta-analysis. Overall, significantly elevated AML risk was associated with NQO1 C609T variant genotypes when all studies were pooled into the meta-analysis (TT vs. CC: OR = 1.44, 95% CI = 1.15-1.81; dominant model: OR = 1.35, 95% CI = 1.09-1.68). In the subgroup analysis by ethnicity, significantly increased risks were found for Asians (OR = 1.47, 95% CI = 1.13-1.93, P = 0.005, I(2) = 48.4%, P = 0.071 for heterogeneity). When stratified by studies of adults or children, statistically significantly elevated risks were found among adults (OR = 1.37, 95% CI = 1.06-1.76, P = 0.017, I(2) = 42.2%, P = 0.097 for heterogeneity). The accumulated evidence indicates that NQO1 C609T seems to confer a risk factor for AML among Asians and adults. Significant between-study heterogeneity was observed, thus more studies based on larger case-control population are required to further evaluate the role of NQO1 C609T polymorphism in AML.

Impact on survival and toxicity by duration of weight extremes during treatment for pediatric acute lymphoblastic leukemia: A report from the Children's Oncology Group

PURPOSE

Previous studies regarding the influence of weight on event-free survival (EFS) and treatment-related toxicity (TRT) in childhood acute lymphoblastic leukemia (ALL) considered only weight at diagnosis. Inasmuch as weight varies substantially over treatment, we hypothesized its impact on EFS is instead determined by cumulative time spent at an extreme weight during therapy and on TRT by weight at the time of toxicity.

PATIENTS AND METHODS

In a cohort of 2,008 children treated for high-risk ALL in Children's Oncology Group study CCG-1961, we determined the effect on EFS of cumulative time receiving therapy at an extreme weight (either obese or underweight) between end of induction and start of maintenance therapy. We also evaluated the association between weight category and incidence and patterns of TRT during 13,946 treatment courses.

RESULTS

Being obese or underweight at diagnosis and for ≥ 50% of the time between end of induction and start of maintenance therapy resulted in inferior EFS (hazard ratios, 1.43 and 2.30, respectively; global P < .001). Normalization of weight during that period resulted in mitigation of this risk comparable to never being obese or underweight. Obese or underweight status at start of each treatment course was significantly associated with specific patterns of TRT.

CONCLUSION

Influence of weight extremes on EFS and TRT is not set at diagnosis as previously reported but is moderated by subsequent weight status during intensive postinduction treatment phases. These observations suggest that weight is a potentially addressable risk factor to improve EFS and morbidity in pediatric ALL.

Lower frequency of NPM1 and FLT3-ITD mutations in a South African adult de novo AML cohort

INTRODUCTION

Acute myeloid leukemia (AML) is a heterogeneous clonal disorder of hemopoietic progenitor cells diagnosed in individuals of any age, but with a median age of 67 years at presentation in adults. Assessment of the mutation status of nucleophosmin protein-1 (NPM1) and FMS-like tyrosine kinase 3 internal tandem duplication (FLT3-ITD) is essential for the prognosis, and treatment of AML.

METHODS

A total of 160 de novo AML cases, both cytogenetically normal and abnormal, were analyzed for the presence of NPM1 and FLT3-ITD mutations, and the results assessed in conjunction with epidemiological, clinical, and laboratory findings.

RESULTS

Nucleophosmin protein-1 mutations were found in 7.5%, while FLT3-ITD was present in 12% of these cases. Both of these were lower than expected. The median age at diagnosis of AML was 41 years, and for the FLT3-ITD only cases, median age was 33 years; these ages were younger than expected.

CONCLUSION

The lower reported frequencies and younger median age at diagnosis of AML and these specific mutations may be contributed to by a number of factors including effects of race on age of presentation, inclusion of patients diagnosed with de novo AML only, and a generally younger median age of the South African population.

Infectious morbidity by catheter type in neutropenic children with cancer

BACKGROUND

Three central venous catheters types are commonly used in pediatric cancer: totally implantable catheters (ICs; eg, mediports, portacaths), tunneled externalized catheters (eg Broviac® or Hickman® catheters [Bard Medical]) and peripherally inserted central catheters. While previous studies have examined risks for catheter-related infections, this is the first large multicenter study to compare catheter-associated infectious morbidity through patient outcomes and hospital utilization.

METHODS

A historical cohort analysis was conducted using data from the Pediatric Health Information System reporting 1167 hospitalizations of neutropenic patients with childhood cancer and a central venous catheters. Multivariate analyses controlled for age, ethnicity, gender, malignancy category and transplant status. Outcomes included incidence of serious bacterial infection, mortality, duration of hospitalization, time and use of intensive care unit and antibiotic usage.

RESULTS

Neutropenic cancer patients with totally ICs (n = 429) have a statistically significant approximately 50% decrease in length of hospitalization (P < 0.001), risk for requiring an intensive care unit stay (P = 0.002), documented serious bacterial infection (P = 0.001) and days on antibiotics (P < 0.001) when compared with patients with tunneled externalized catheters (n = 463). Similar differences were found comparing hospitalizations of patients with ICs to those with peripherally inserted central catheters (n = 275). No difference in mortality was observed among catheters groups.

CONCLUSIONS

In neutropenic pediatric oncology patients with a central venous catheters, ICs are associated with the least hospital utilization including shortest duration of hospitalization, intensive care unit time and antibiotic therapy when compared with tunneled external catheters and peripherally inserted central catheters. The impact of differences in catheter-associated infectious morbidity on patient outcomes and hospital utilization should be included in clinical decision making.

Low socioeconomic status is associated with worse survival in children with cancer: a systematic review

BACKGROUND

While low socioeconomic status (SES) has been associated with inferior cancer outcome among adults, its impact in pediatric oncology is unclear. Our objective was therefore to conduct a systematic review to determine the impact of SES upon outcome in children with cancer.

METHODS

We searched Ovid Medline, EMBASE and CINAHL from inception to December 2012. Studies for which survival-related outcomes were reported by socioeconomic subgroups were eligible for inclusion. Two reviewers independently assessed articles and extracted data. Given anticipated heterogeneity, no quantitative meta-analyses were planned a priori.

RESULTS

Of 7,737 publications, 527 in ten languages met criteria for full review; 36 studies met final inclusion criteria. In low- and middle-income countries (LMIC), lower SES was uniformly associated with inferior survival, regardless of the measure chosen. The majority of associations were statistically significant. Of 52 associations between socioeconomic variables and outcome among high-income country (HIC) children, 38 (73.1%) found low SES to be associated with worse survival, 15 of which were statistically significant. Of the remaining 14 (no association or high SES associated with worse survival), only one was statistically significant. Both HIC studies examining the effect of insurance found uninsured status to be statistically associated with inferior survival.

CONCLUSIONS

Socioeconomic gradients in which low SES is associated with inferior childhood cancer survival are ubiquitous in LMIC and common in HIC. Future studies should elucidate mechanisms underlying these gradients, allowing the design of interventions mediating socioeconomic effects. Targeting the effect of low SES will allow for further improvements in childhood cancer survival.

The effect of XPD/ERCC2 Lys751Gln polymorphism on acute leukemia risk: a systematic review and meta-analysis

AIMS

Epidemiological studies have assessed the association between xeroderma pigmentosum group D (XPD) Lys751Gln and acute leukemia risk with conflicting results. We performed this meta-analysis to derive a more precise estimation of the relationship. Pooled odds ratio (OR) with 95% confidence interval (95% CI) was used to assess the strength of the association.

RESULTS

Ten published case-control studies including a total of 1494 cases and 2259 controls were identified. Overall, significant risk effects of Lys751Gln genotype was found under the dominant model (OR=1.16; 95% CI=1.01-1.34; P=0.032). When stratified by clinical types, the variant genotype was associated with the acute myeloid leukemia (AML) risk under the heterozygote comparison (OR=1.20; 95% CI=1.00-1.43; P=0.048), the homozygote comparison (OR=1.35; 95% CI=1.05-1.74; P=0.019) and the dominant model (OR=1.23; 95% CI=1.04-1.45; P=0.015), respectively. Furthermore, significantly increased risks were also pronounced in Caucasian AML patients (the homozygote comparison: OR=1.38; 95% CI=1.07-1.78; P=0.013; the dominant model: OR=1.23; 95% CI=1.03-1.46; P=0.020; and the recessive model: OR=1.26; 95% CI=1.00-1.60; P=0.050). No evident heterogeneities were observed for the overall data under all genetic models. In addition, no statistical evidence for publication bias was found using the method of Begg's and Egger's tests.

CONCLUSION

This meta-analysis suggested that XPD Lys751Gln polymorphism might be a risk factor for AML and Caucasian acute leukemia patients.

Genomics of racial and ethnic disparities in childhood acute lymphoblastic leukemia

Although the cure rates of childhood acute lymphoblastic leukemia (ALL) have improved dramatically in the past 40 years, not all children have benefited equally from this impressive progress. Racial and ethnic disparities in the incidence and treatment outcome of childhood ALL persist, with Hispanic children having an elevated risk of developing ALL and one of the lowest survival rates after ALL therapy. A critical barrier to progress is the lack of an understanding of the causes of ALL disparities, particularly racial and ethnic differences in ALL biology. In this review, the authors summarize the current knowledge on population variation in childhood ALL incidence and treatment outcome, discuss the contributing genetic and nongenetic variables, and highlight possible therapeutic interventions to mitigate disparities in ALL.

Clinical characteristics, response to therapy, and survival of African American patients diagnosed with chronic lymphocytic leukemia: joint experience of the MD Anderson Cancer Center and Duke University Medical Center

BACKGROUND

Little is known regarding racial disparities in characteristics and outcomes among patients with chronic lymphocytic leukemia (CLL).

METHODS

The characteristics and outcomes of untreated African American (AA) patients with CLL (n = 84) were analyzed and compared with a reference nonblack (NB) patient population (n = 1571).

RESULTS

At the time of presentation, AA patients had lower median hemoglobin levels (12.9 g/dL vs 13.7 g/dL), higher β2 microglobulin levels (2.7 mg/dL vs 2.4 mg/dL), greater frequency of constitutional symptoms (27% vs 10%), unmutated immunoglobulin heavy-chain variable region (IGHV) mutation status (65% vs 47%), ζ-chain-associated protein kinase 70 (ZAP70) expression (58% vs 32%), and deletion of chromosome 17p or chromosome 11q (28% vs 17%; P ≤ 02 for each comparison). Fifty-one percent of AA patients and 39% of NB patients required first-line therapy and 91% and 88%, respectively, received chemoimmunotherapy. Overall response rates to treatment were 85% for AA patients and 94% for NB patients (P = .06); and the complete response rates were 56% and 58%, respectively (P = .87). The median survival of AA patients was shorter compared with that of NB patients (event-free survival: 36 months vs 61 months; P = .007; overall survival: 152 months vs not reached; P = .0001). AA race was an independent predictor of shorter event-free and overall survival in multivariable regression models.

CONCLUSIONS

The current results indicated that AA patients with CLL have more unfavorable prognostic characteristics and shorter survival compared with their NB counterparts.

XRCC1 Arg399Gln variation and leukemia susceptibility: evidence from 2,647 cases and 5,518 controls

Previous reports implicate XRCC1 Arg399Gln polymorphism as a possible risk factor for several cancers. Increasing studies have been conducted on the association of XRCC1 Arg399Gln polymorphisms with susceptibility to leukemia. However, conflicting results have been generated. The goal of the present study was to derive a more precise estimation of the relationship. Meta-analyses assessing the association of XRCC1 Arg399Gln variation with leukemia were conducted, and subgroup analyses on ethnicity and clinical types were further performed. Eligible studies were identified for the period up to February 2013. Consequently, 16 publications including 17 case-control studies with 2,647 cases and 5,518 controls were selected for analysis. The overall data indicated a significant association of XRCC1 Arg399Gln polymorphism with leukemia risk (Gln/Gln versus Arg/Arg: OR = 1.37, 95% confidence interval (CI) = 1.08-1.74; dominant model: OR = 1.23, 95%CI = 1.03-1.46; recessive model: OR = 1.23, 95%CI = 1.06-1.44). In the subgroup analysis by ethnicity, Gln allele may increase leukemia susceptibility among Asians (Gln/Gln versus Arg/Arg: OR = 1.82, 95%CI = 1.19-2.78; dominant model: OR = 1.53, 95%CI = 1.00-2.33; recessive model: OR = 1.51, 95%CI = 1.11-2.06), but not Caucasians or mixed ethnicities. In the subgroup analysis by clinical types, increased risk was observed in acute lymphocytic leukemia (ALL) subgroup (Gln/Gln versus Arg/Arg: OR = 1.45, 95%CI = 1.09-1.93; recessive model: OR = 1.30, 95%CI = 1.00-1.69), but not in acute myeloid leukemia, chronic lymphocytic leukemia, or chronic myeloid leukemia subgroups, respectively. Collectively, the results of the present study suggest that XRCC1 Arg399Gln polymorphism might be a low-penetrant risk factor for leukemia, particularly among Asians. Homozygous Gln/Gln alleles might have a correlation with increased ALL susceptibility.

Ethnicity and age disparities in Ewing sarcoma outcome

This institutional retrospective review studied Ewing sarcomas from 1987-2011. Among 135 patients, 127 (19 Hispanic and 108 white/non-Hispanic) were analyzed (excluding small sample sized groups) finding 15% Hispanic, 85% non-Hispanic, 27% <18 years, 21% >40 years and 1-272 months follow-up (median 41). Age was significantly associated with overall survival (OS) (p = 0.01), whereby <18 years had a higher probability of 5-year survival (OS 61%) than >40 years (OS 37.6%). Ethnicity was marginally statistically significant (OS, p = 0.065); whereby median survival was clinically significant (white non-Hispanic 63 months and Hispanic 23 months). Hispanic ethnicity and older age are independent poor prognostic factors.

Children's Oncology Group's 2013 blueprint for research: survivorship and outcomes

Improvements in the treatment of childhood cancer have resulted in over 360,000 survivors of childhood cancer in the U.S. There is now a heightened recognition of the need to reduce treatment-related sequelae and optimize the quality of life of children treated for cancer. Survivorship studies conducted in the cooperative group setting have provided us with important information on long-term intellectual function, organ toxicity, reproductive outcomes, second cancers, late mortality, and disparities in outcomes. Ongoing health education initiatives have helped standardize the follow-up care for childhood cancer survivors and facilitate the early transfer of health-related information to patients, families, and healthcare providers.

Anti-CRLF2 Antibody-Armored Biodegradable Nanoparticles for Childhood B-ALL

B-precursor acute lymphoblastic leukemia (B-ALL) lymphoblast (blast) internalization of anti-cytokine receptor-like factor 2 (CRLF2) antibody-armored biodegradable nanoparticles (AbBNPs) are investigated. First, AbBNPsaere synthesized by adsorbing anti-CRLF2 antibodies to poly(D,L-lactide- co -glycolide) (PLGA) nanoparticles of various sizes and antibody surface density (Ab/BNP) ratios. Second, AbBNPs are incubated with CRLF2-overexpressing (CRLF2+) or control blasts. Third, internalization of AbBNPs by blasts is evaluated by multicolor flow cytometry as a function of receptor expression, AbBNP size, and Ab/BNP ratio. Results from these experiments are con-firmed by electron microscopy, fluorescence microscopy, and Western blotting. The optimal size and Ab/BNP for internalization of AbBNPs by CRLF2+ blasts is 50 nm with 10 Ab/BNP and 100 nm with 25 Ab/BNP. These studies show that internalization of AbBNPs in childhood B-ALL blasts is AbBNP size-and Ab/BNP ratio-dependent. All AbBNP combinations are non-cytotoxic. It is also shown that CD47 is very slightly up-regulated by blasts exposed to AbBNPs. CD47 is "the marker of self" overexpressed by blasts to escape phagocytosis, or "cellular devouring", by beneficial macrophages. The results indicate that precise engineering of AbBNPs by size and Ab/BNP ratio may improve the internalization and selectivity of future biodegradable nanoparticles for the treatment of leukemia patients, including drug-resistant minority children and Down's syndrome patients with CRLF2+B-ALL.

Leveraging epidemiology and clinical studies of cancer outcomes: recommendations and opportunities for translational research

As the number of cancer survivors continues to grow, research investigating the factors that affect cancer outcomes, such as disease recurrence, risk of second malignant neoplasms, and the late effects of cancer treatments, becomes ever more important. Numerous epidemiologic studies have investigated factors that affect cancer risk, but far fewer have addressed the extent to which demographic, lifestyle, genomic, clinical, and psychosocial factors influence cancer outcomes. To identify research priorities as well as resources and infrastructure needed to advance the field of cancer outcomes and survivorship research, the National Cancer Institute sponsored a workshop titled "Utilizing Data from Cancer Survivor Cohorts: Understanding the Current State of Knowledge and Developing Future Research Priorities" on November 3, 2011, in Washington, DC. This commentary highlights recent findings presented at the workshop, opportunities to leverage existing data, and recommendations for future research, data, and infrastructure needed to address high priority clinical and research questions. Multidisciplinary teams that include epidemiologists, clinicians, biostatisticians, and bioinformaticists will be essential to facilitate future cancer outcome studies focused on improving clinical care of cancer patients, identifying those at high risk of poor outcomes, and implementing effective interventions to ultimately improve the quality and duration of survival.

Normal karyotype CALLA-positive adult pre-B ALL: dismal outcome with chemotherapy for patients with loss/gain of ABL1 and/or BCR FISH signals

BACKGROUND

Diagnostic karyotype and molecular studies represent the most powerful prognostic indicators in acute myeloid leukemia and provide the framework for risk stratification. Risk stratification in ALL has also a vital role in predicting outcome and identifying patients at higher risk of relapse with multiagent chemotherapy, but the role of diagnostic karyotype and molecular markers in adult ALL is limited to few well recognized cytogenetic abnormalities.

PATIENTS AND METHODS

We report a case series of 6 adult ALL patients with a characteristic molecular abnormality that have done poorly with chemotherapy. Between April 2004 and November 2009, 72 adult ALL patients (Pre-B-cell 61; T-cell 11) were referred to and treated at the Leukemia/BMT Program of BC in Vancouver, Canada. FISH for BCR-ABL fusion was positive in 12 of 61 Pre-B cell ALL patients. An additional 6 patients were negative for this typical fusion but had FISH abnormalities related to BCR and/or ABL1.

RESULTS

In this report, we describe the clinical and hematopathologic characteristics of these 6 patients and their poor outcome. We review the literature where only 2 similar cases with normal karyotype Pre-B ALL and associated FISH BCR/ABL1 numerical abnormalities were found.

CONCLUSION

We recommend screening all adult pre-B ALL patients with normal karyotype for this clonal abnormality and suggest classifying these ALL patients into the high-risk category.

Association between CYP1A1 Ile462Val variation and acute leukemia risk: meta-analyses including 2164 cases and 4160 controls

BACKGROUND

Previously, CYP1A1 Ile462Val polymorphism has been indicated to be a risk factor for several malignancies. Increasing reports have focused on the association of CYP1A1 Ile462Val polymorphisms with susceptibility to acute leukemia and have generated controversial results. The goal of the present study was to derive a more precise estimation of the relationship.

METHODS

Relevant literature has been rigorously searched and screened. Eligible studies were identified for the period up to Apr 2012. Meta-analyses evaluating the association of CYP1A1 Ile462Val variation with acute leukemia were carried out. Subgroup analyses on ethnicity, clinical types and source of controls were further performed.

RESULTS

A total of thirteen publications including fourteen case-control studies with 2164 cases and 4160 controls were selected for analysis. The overall data indicated a significant association of CYP1A1 Ile462Val polymorphism with acute leukemia risk (Val/Val vs Ile/Ile OR = 1.49; 95% CI = 1.11-1.98; dominant model: OR = 1.26; 95% CI = 1.05-1.51; recessive model: OR = 1.38; 95% CI = 1.04-1.83). In subgroup analysis on ethnicity, increased risk was shown among mixed ethnicities (Val/Val vs Ile/Ile: OR = 2.36; 95% CI = 1.46-3.82; dominant model: OR = 1.37; 95% CI = 1.01-1.86; recessive model: OR = 2.20; 95% CI = 1.37-3.53) but not Asians or Caucasians. In subgroup analysis on clinical types, increased risk was observed in the acute lymphocytic leukemia (ALL) subgroup (Val/Val vs Ile/Ile: OR = 2.06; 95% CI = 1.42-3.01; recessive model: OR = 1.91; 95% CI = 1.32-2.76) but not in the acute myeloid leukemia (AML) subgroup.

CONCLUSION

The results of the present study suggest that CYP1A1 Ile462Val polymorphism might be a low-penetrant risk factor for acute leukemia. Subgroup analyses suggest that homozygous Val/Val alleles might modify the susceptibility to ALL.

Pharmacogenetic analysis of pediatric patients with acute lymphoblastic leukemia: a possible association between survival rate and ITPA polymorphism

Genetic polymorphisms are important factors in the effects and toxicity of chemotherapeutics. To analyze the pharmacogenetic and ethnic differences in chemotherapeutics, major genes implicated in the treatment of acute lymphoblastic leukemia (ALL) were analyzed. Eighteen loci of 16 genes in 100 patients with ALL were analyzed. The distribution of variant alleles were CYP3A4*1B (0%), CYP3A5*3 (0%), GSTM1 (21%), GSTP1 (21%), GSTT1 (16%), MDR1 exon 21 (77%), MDR1 exon 26 (61%), MTHFR 677 (63%), MTHFR 1298 (29%), NR3C1 1088 (0%), RFC1 80 (68%), TPMT combined genotype (7%), VDR intron 8 (11%), VDR FokI (83%), TYMS enhancer repeat (22%) and ITPA 94 (30%). The frequencies of single nucleotide polymorphisms (SNPs) of 10 loci were statistically different from those in Western Caucasians. Dose percents (actual/planned dose) or toxicity of mercaptopurine and methotrexate were not related to any SNPs. Event free survival (EFS) rate was lower in ITPA variants, and ITPA 94 AC/AA variant genotypes were the only independent risk factor for lower EFS in multivariate analysis, which was a different pharmacogenetic implication from Western studies. This study is the first pharmacogenetic study in Korean pediatric ALL. Our result suggests that there are other possible pharmacogenetic factors besides TPMT or ITPA polymorphisms which influence the metabolism of mercaptopurine in Asian populations.

Understanding disparities in leukemia: a national study

PURPOSE

Disparities in solid tumors have been well studied. However, disparities in hematologic malignancies have been relatively unexplored on population-based levels. The purpose of this study is to examine the relationship between race/ethnicity and acute leukemia mortality.

METHODS

All patients with acute leukemia [acute lymphoblastic leukemia (ALL) and acute myelogenous leukemia (AML)] were identified in the Surveillance Epidemiology and End Results database, 1999-2008. Kaplan-Meier curves were generated to reflect survival probabilities by race/ethnicity. Multivariable Cox proportional hazard models estimated hazard of mortality by race with adjustment for individual (age, gender, year of diagnosis) and select genetic factors.

RESULTS

A total of 39,002 patients with acute leukemia were included in the study. Overall, there was a mortality disparity in acute leukemia for blacks (HR 1.17, p < 0.0001) and Hispanics (HR 1.13, p < 0.0001) compared with non-Hispanic whites. In stratified analysis, disparities in ALL were greater than AML; blacks (HR[ALL]1.45, p < 0.0001; HR[AML]1.12, p < 0.0011); Hispanics (HR[ALL]1.46, p < 0.0001; HR[AML]1.06, p < 0.0001). Adjustment for individual patient and select genetic factors did not explain disparities.

CONCLUSIONS

Blacks and Hispanics suffer decreased survival in acute leukemia as compared to others. Further investigation is needed to understand the drivers of poor cancer outcomes in these populations.

MDM2 SNP309 variation contributes to leukemia risk: meta-analyses based on 7259 subjects

Evidence implicates MDM2 (murine double minute-2) T309G polymorphism as a risk factor for several cancers. Increasing numbers of studies have been carried out on the association of MDM2 T309G polymorphism with susceptibility to leukemia and have generated conflicting results. The aim of the present study was to derive a more precise estimation of the relationship. Meta-analyses assessing the association of MDM2 T309G variation with leukemia were conducted. Separate analyses on ethnicity and clinical types were also performed. Eligible studies were identified for the period up to February 2012. Consequently, seven publications including eight case-control studies with 1777 cases and 5482 controls were selected for analysis. The overall data indicated a significant association of the MDM2 T309G polymorphism with leukemia risk (GG vs. TT: odds ratio [OR] = 1.62; 95% confidence interval [CI] = 1.14-2.29; dominant model: OR = 1.20; 95% CI = 1.06-1.36; recessive model: OR = 1.47; 95% CI = 1.07-2.03). In subgroup analysis by ethnicity, the G allele may increase leukemia susceptibility among Asians (GG vs. TT: OR = 3.06; 95% CI = 2.05-4.56; dominant model: OR = 1.82; 95% CI = 1.31-2.51; recessive model: OR = 2.32; 95% CI = 1.69-3.19) but not Caucasians. In subgroup analysis by clinical types, data suggested increased risk for acute myeloid leukemia (AML) and chronic myeloid leukemia (CML) under additive and recessive models, respectively. Similarly, elevated risk for chronic lymphocytic leukemia (CLL) was shown under the dominant model. Collectively, the results of the present study suggest that MDM2 T309G polymorphism might be a low-penetrant risk factor for leukemia among Asians but not Caucasians. The G allele might increase CLL susceptibility and homozygous GG might elevate AML and CML risk.

Nonadherence to oral mercaptopurine and risk of relapse in Hispanic and non-Hispanic white children with acute lymphoblastic leukemia: a report from the children's oncology group

PURPOSE

Systemic exposure to mercaptopurine (MP) is critical for durable remissions in children with acute lymphoblastic leukemia (ALL). Nonadherence to oral MP could increase relapse risk and also contribute to inferior outcome in Hispanics. This study identified determinants of adherence and described impact of adherence on relapse, both overall and by ethnicity.

PATIENTS AND METHODS

A total of 327 children with ALL (169 Hispanic; 158 non-Hispanic white) participated. Medication event-monitoring system caps recorded date and time of MP bottle openings. Adherence rate, calculated monthly, was defined as ratio of days of MP bottle opening to days when MP was prescribed.

RESULTS

After 53,394 person-days of monitoring, adherence declined from 94.7% (month 1) to 90.2% (month 6; P < .001). Mean adherence over 6 months was significantly lower among Hispanics (88.4% v 94.8%; P < .001), patients age ≥ 12 years (85.8% v 93.1%; P < .001), and patients from single-mother households (80.6% v 93.1%; P = .001). A progressive increase in relapse was observed with decreasing adherence (reference: adherence ≥ 95%; 94.9% to 90%: hazard ratio [HR], 4.1; 95% CI,1.2 to 13.5; P = .02; 89.9% to 85%: HR, 4.0; 95% CI, 1.0 to 15.5; P = .04; < 85%: HR. 5.7; 95% CI, 1.9 to 16.8; P = .002). Cumulative incidence of relapse (± standard deviation) was higher among Hispanics (16.5% ± 4.0% v 6.3% ± 2.2%; P = .02). Association between Hispanic ethnicity and relapse (HR, 2.6; 95% CI, 1.1 to 6.1; P = .02) became nonsignificant (HR, 1.8; 95% CI, 0.6 to 5.2; P = .26) after adjusting for adherence and socioeconomic status. At adherence rates ≥ 90%, Hispanics continued to demonstrate higher relapse, whereas at rates < 90%, relapse risk was comparable to that of non-Hispanic whites.

CONCLUSION

Lower adherence to oral MP increases relapse risk. Ethnic difference in relapse risk differs by level of adherence-an observation currently under investigation.

Using germline genomics to individualize pediatric cancer treatments

The amazing successes in cure rates for children with cancer over the last century have come in large part from identifying clinical, genetic, and molecular variables associated with response to therapy in large cooperative clinical trials and stratifying therapies according to the predicted risk of relapse. There is an expanding interest in identifying germline genomic variants, as opposed to genetic variants within the tumor, that are associated with susceptibility to toxicity and for risk of relapse. This review highlights the most important germline pharmacogenetic and pharmacogenomic studies in pediatric oncology. Incorporating germline genomics into risk-adapted therapies will likely lead to safer and more effective treatments for children with cancer.

Racial and ethnic disparities in survival of US children with acute lymphoblastic leukemia: evidence from the SEER database 1988-2008

PURPOSE

Prior studies have shown poorer survival from childhood acute lymphoblastic leukemia (ALL) among some minorities compared to non-Hispanic whites (NHW). Here, we examine whether these survival disparities have persisted and to see whether they also exist for Asian and Hispanic subgroups.

METHODS

Using data from the US National Cancer Institute's Surveillance, Epidemiology and End Results program from 1988 to 2008, we compared all natural-cause survival for children aged 19 years or under diagnosed with ALL using Cox proportional hazards models adjusted for age, diagnosis year, gender and disease immunophenotype.

RESULTS

Black, Hispanic and Native American children continue to have significantly poorer survival than NHW. Unlike previous studies, we found that Asian Americans also had significantly worse survival. Among Asian subgroups, Vietnamese (relative risk [RR] = 2.44, 95 % CI = 1.50-3.97) and Filipinos (RR = 1.64, 95 % CI = (1.13-2.38) had significantly poorer survival, while other East Asian groups, except Chinese, had non-significantly worse survival. Most Hispanic subgroups had RRs around 2.

CONCLUSION

Previously observed poorer prognosis for childhood ALL for some minority groups appears to be shared by most Asians as well. Further research is needed to find explanations for the poorer survival of minority children with ALL and possible treatment implications.

ARID5B genetic polymorphisms contribute to racial disparities in the incidence and treatment outcome of childhood acute lymphoblastic leukemia

PURPOSE

Recent genome-wide screens have identified genetic variations in ARID5B associated with susceptibility to childhood acute lymphoblastic leukemia (ALL). We sought to determine the contribution of ARID5B single nucleotide polymorphisms (SNPs) to racial disparities in ALL susceptibility and treatment outcome.

PATIENTS AND METHODS

We compared the association between ARID5B SNP genotype and ALL susceptibility in whites (> 95% European genetic ancestry; 978 cases and 1,046 controls) versus in Hispanics (> 10% Native American ancestry; 330 cases and 541 controls). We determined the relationships between ARID5B SNP genotype and ALL relapse risk in 1,605 children treated on the Children's Oncology Group (COG) P9904/9905 clinical trials.

RESULTS

Among 49 ARID5B SNPs interrogated, 10 were significantly associated with ALL susceptibility in both whites and Hispanics (P < .05), with risk alleles consistently more frequent in Hispanics than in whites. rs10821936 exhibited the most significant association in both races (P = 8.4 × 10(-20) in whites; P = 1 × 10(-6) in Hispanics), and genotype at this SNP was highly correlated with local Native American genetic ancestry (P = 1.8 × 10(-8)). Multivariate analyses in Hispanics identified an additional SNP associated with ALL susceptibility independent of rs10821936. Eight ARID5B SNPs were associated with both ALL susceptibility and relapse hazard; the alleles related to higher ALL incidence were always linked to poorer treatment outcome and were more frequent in Hispanics.

CONCLUSION

ARID5B polymorphisms are important determinants of childhood ALL susceptibility and treatment outcome, and they contribute to racial disparities in this disease.

A grounded theory of the process of adherence to oral chemotherapy in Hispanic and caucasian children and adolescents with acute lymphoblastic leukemia

Children and adolescents with acute lymphoblastic leukemia (ALL) receive treatment that relies on daily self- or parent/caregiver-administered oral chemotherapy for approximately 2 years. Despite the fact that pediatric ALL is uniformly fatal without adequate treatment, nonadherence to oral chemotherapy has been observed in up to one third of patients. Little is known about the reasons for nonadherence in these patients. This study used Straussian grounded theory methodology to develop and validate a model to explain the process of adherence to oral chemotherapy in children and adolescents with ALL. Thirty-eight semistructured interviews (with 17 patients and 21 parents/caregivers) and 4 focused group discussions were conducted. Three stages were identified in the process of adherence: (a) Recognizing the Threat, (b) Taking Control, and (c) Managing for the Duration. Doing Our Part was identified as the core theme explaining the process of adherence and involves the parent (or patient) taking responsibility for assuring that medications are taken as prescribed. Understanding the association between taking oral chemotherapy and control/cure of leukemia (Making the Connection) appeared to mediate adherence behaviors.

Disparities in cancer outcomes: lessons learned from children with cancer

Disparities in cancer burden by race/ethnicity have been reported, primarily in adults with cancer. However, there appear to be gaps in the pediatric oncology literature with regards to a comprehensive overview on this topic. Extant literature is used to highlight the results of studies focusing on racial and ethnic disparities in outcome observed in selected childhood cancers. A comprehensive approach is utilized to understand possible underlying causes of disparities in cancer outcomes, and to highlight the gaps that currently exist. This review helps define areas of future research that could help develop targeted, disease-specific approaches to eliminate the disparities.

Ancestry and pharmacogenomics of relapse in acute lymphoblastic leukemia

Although five-year survival rates for childhood acute lymphoblastic leukemia (ALL) are now over 80% in most industrialized countries, not all children have benefited equally from this progress. Ethnic differences in survival after childhood ALL have been reported in many clinical studies, with poorer survival observed among African Americans or those with Hispanic ethnicity when compared with European Americans or Asians. The causes of ethnic differences remain uncertain, although both genetic and non-genetic factors are likely important. Interrogating genome-wide germline SNP genotypes in an unselected large cohort of children with ALL, we observed that the component of genomic variation that co-segregated with Native American ancestry was associated with risk of relapse (P = 0.0029) even after adjusting for known prognostic factors (P = 0.017). Ancestry-related differences in relapse risk were abrogated by the addition of a single extra phase of chemotherapy, indicating that modifications to therapy can mitigate the ancestry-related risk of relapse.

Racial differences in the incidence of mesenchymal tumors associated with EWSR1 translocation

BACKGROUND

The incidence of Ewing sarcoma varies by race, with very low rates among persons of African and East Asian ancestry. The incidence by race of other mesenchymal tumors that also harbor EWSR1 translocations has not been studied.

METHODS

The SEER database was queried to find cases of mesenchymal tumors associated with EWSR1 translocations: Ewing sarcoma; clear cell sarcoma; extraskeletal myxoid chondrosarcoma; myxoid liposarcoma; desmoplastic small round cell tumor; and myoepithelial tumor. Age-adjusted incidence rates were calculated for white, African American, and Asian/Native American populations and compared statistically.

RESULTS

Ewing sarcoma was significantly less common in the African American and Asian/Native American populations compared with the white population, with incidence rate ratios of 0.12 (95% CI, 0.08-0.20; P<0.001) and 0.54 (95% CI, 0.41-0.69; P<0.001), respectively. Desmoplastic small round cell tumor was significantly more common in the African American population compared with the white population (incidence rate ratio=3.0; 95% CI, 1.62-5.49; P<0.001). Myxoid liposarcoma was significantly less common in the Asian/Native American population compared with the white population (incidence rate ratio=0.72; 95% CI, 0.56-0.92; P=0.006). The incidence rates for extraskeletal myxoid chondrosarcoma, myoepithelial tumors, and clear cell sarcoma did not differ significantly by race.

CONCLUSIONS

Tumors associated with EWSR1 translocation are not uniformly more common in people of European ancestry.

IMPACT

The relationship between race and EWSR1 somatic translocation is complex. Future studies investigating the genetic epidemiology of EWSR1 translocated tumors are required.

Racial and ethnic disparities in risk and survival in children with neuroblastoma: a Children's Oncology Group study

PURPOSE

Although health disparities are well-described for many cancers, little is known about racial and ethnic disparities in neuroblastoma. To evaluate differences in disease presentation and survival by race and ethnicity, data from the Children's Oncology Group (COG) were analyzed.

PATIENTS AND METHODS

The racial/ethnic differences in clinical and biologic risk factors, and outcome of patients with neuroblastoma enrolled on COG ANBL00B1 between 2001 and 2009 were investigated.

RESULTS

A total of 3,539 patients (white, 72%; black, 12%; Hispanic, 12%; Asian, 4%; and Native American, < 1%) with neuroblastoma were included. The 5-year event-free survival (EFS) rates were 67% for whites (95% CI, 65% to 69%), 69% for Hispanics (95% CI, 63% to 74%), 62% for Asians (95% CI, 51% to 71%), 56% for blacks (95% CI, 50% to 62%), and 37% for Native American (95% CI, 17% to 58%). Blacks (P < .001) and Native Americans (P = .04) had a higher prevalence of high-risk disease than whites, and significantly worse EFS (P = .01 and P = .002, respectively). Adjustment for risk group abrogated these differences. However, closer examination of the EFS among high-risk patients who remained event free for 2 years or longer, revealed a higher prevalence of late-occurring events among blacks compared with whites (hazard ratio, 1.5; 95% CI, 1.0 to 2.3; P = .04).

CONCLUSION

Black and Native American patients with neuroblastoma have a higher prevalence of high-risk disease, accounting for their worse EFS when compared with whites. The higher prevalence of late-occurring events among blacks with high-risk disease suggests that this population may be more resistant to chemotherapy. Studies focused on delineating the genetic basis for the racial disparities observed in this study are planned.

Frequencies of ETV6-RUNX1 fusion and hyperdiploidy in pediatric acute lymphoblastic leukemia are lower in far east than west

BACKGROUND

Both ETV6-RUNX1 (TEL-AML1) fusion and hyperdiploidy (>50 chromosomes) in transformed lymphoblasts are favorable genetic features in childhood acute lymphoblastic leukemia (ALL).

PROCEDURE

Among 433 Taiwanese children with ALL diagnosed at our hospitals between 1997 and 2007, the ETV6-RUNX1 fusion was found in 15.8%, and hyperdiploidy (>50 chromosomes) in 14.1% of the patients. These frequencies were lower than those reported in the West, leading us to conduct a meta-analysis of ETV6-RUNX1 fusion and hyperdiploidy frequencies in childhood ALL based on published reports.

RESULTS

The frequency of ETV6-RUNX1 fusion in the Far East (Japan, Korea, China, Hong Kong, Chinese in Singapore, and Taiwan) was 13.4% (177/1,321, range: 9-23%, median 13%), significantly lower than the 22.8% (1,664/7,291, range: 19-26%, median 23%) in the West (West Europe and the United States) (P < 0.001, odds ratio = 2.0, 95% CI: 1.7-2.4). Similarly, the frequency of hyperdiploidy in Japan and Taiwan was 14.3% (333/2,334, range: 12-20%, median 16%), significantly lower than the 25.2% in the West (5,173/20,510, range: 18-34%, median 23.5%; P < 0.001, odds ratio = 2.0, 95% CI: 1.8-2.3).

CONCLUSIONS

This meta-analysis demonstrates lower frequencies of ETV6-RUNX1 fusion and hyperdiploidy among leukemia patients in the Far East compared with the West. The integral relationship of these genetic features with a favorable outcome in childhood ALL warrants further study of potentially important epidemiologic factors, including placental exposure to leukemogenic agents, and host pharmacogenetics.

Identification of novel cluster groups in pediatric high-risk B-precursor acute lymphoblastic leukemia with gene expression profiling: correlation with genome-wide DNA copy number alterations, clinical characteristics, and outcome

To resolve the genetic heterogeneity within pediatric high-risk B-precursor acute lymphoblastic leukemia (ALL), a clinically defined poor-risk group with few known recurring cytogenetic abnormalities, we performed gene expression profiling in a cohort of 207 uniformly treated children with high-risk ALL. Expression profiles were correlated with genome-wide DNA copy number abnormalities and clinical and outcome features. Unsupervised clustering of gene expression profiling data revealed 8 unique cluster groups within these high-risk ALL patients, 2 of which were associated with known chromosomal translocations (t(1;19)(TCF3-PBX1) or MLL), and 6 of which lacked any previously known cytogenetic lesion. One unique cluster was characterized by high expression of distinct outlier genes AGAP1, CCNJ, CHST2/7, CLEC12A/B, and PTPRM; ERG DNA deletions; and 4-year relapse-free survival of 94.7% ± 5.1%, compared with 63.5% ± 3.7% for the cohort (P = .01). A second cluster, characterized by high expression of BMPR1B, CRLF2, GPR110, and MUC4; frequent deletion of EBF1, IKZF1, RAG1-2, and IL3RA-CSF2RA; JAK mutations and CRLF2 rearrangements (P < .0001); and Hispanic ethnicity (P < .001) had a very poor 4-year relapse-free survival (21.0% ± 9.5%; P < .001). These studies reveal striking clinical and genetic heterogeneity in high-risk ALL and point to novel genes that may serve as new targets for diagnosis, risk classification, and therapy.

Geographic and ethnic differences in childhood leukaemia and lymphoma survival: comparisons of Philippine residents, Asian Americans and Caucasians in the United States

Background:

Childhood cancer survival estimates from developing nations are rare.

Methods:

Using the US SEER and the Manila and Rizal Cancer Registry databases in the Philippines, 5-year survival for childhood leukaemia and lymphoma in 2001–2005 among Asian Americans were compared with both Filipinos and Caucasians in the United States. Estimates for patients in the United States in earlier time periods were compared with that of Philippine residents to estimate delay in achievements of comparable levels of survival.

Results:

Childhood leukaemia and lymphoma relative survival was much lower in Filipinos living in the Philippines (32.9 and 47.7%) than in Asian Americans (80.1 and 90.5%) and Caucasians (81.9 and 87%). Achievement of comparable survival rates of Philippine residents lagged behind by 20 to >30 years compared with patients in the United States.

Conclusions:

The large differences in survival estimates of US populations and Philippine residents highlight the deficiencies of paediatric cancer care delivery in the Philippines. The long survival lag underlines the need for major improvements in access to diagnostic and treatment facilities.

Vincristine and intestinal pseudo-obstruction in children: report of 5 cases, literature review, and suggested management

Intestinal pseudo-obstruction is a rare complication resulting from a variety of disorders. Symptoms include abdominal pain, nausea, vomiting, diarrhea, constipation, and malnutrition. Vincristine-related pseudo-obstruction has been reported in the literature, but its description in children and recommendations for management are lacking. A review of the literature revealed 21 reported pediatric cases of vincristine-related pseudo-obstruction. Most have, however, been attributed to a drug interaction with itraconazole, accidental vincristine overdose, or liver failure. Potential genetic causes are rarely addressed. We present here 5 cases of pseudo-obstruction related to vincristine without any identifiable predisposing factors, and a suggested algorithm for management.