Racial and ethnic disparities in pediatric cancer incidence among children and young adults in the United States by single year of age.

BACKGROUND: Incidence rates of pediatric cancers in the United States are typically reported in 5-year age groups, obscuring variation by single year of age. Additionally, racial and ethnic variation in incidence is typically presented in broad categories rather than by narrow age ranges. METHODS: The Surveillance, Epidemiology, and End Results (SEER) 18 data (2000-2017) were examined to calculate frequencies and age-adjusted incidence rates among individuals aged birth to 39 years. Incidence rate ratios (IRRs) and 95% confidence intervals (95% CIs) were estimated as the measure of association for rate comparisons by race and Hispanic origin overall and by single year of age. RESULTS: Several histologic types showed substantial variation in race/ethnicity-specific and overall rates by single year of age. Overall, Black children and young adults experienced substantially decreased incidence of acute lymphoid leukemia (IRR, 0.52; 95% CI, 0.49-0.55) compared to Whites, and this decreased incidence was strongest at ages 1 through 7 years and 16 through 20 years. Hispanic individuals experienced decreased overall incidence of Hodgkin lymphoma (IRR, 0.50; 95% CI, 0.48-0.52) and astrocytoma (IRR, 0.54; 95% CI, 0.52-0.56) and increased risk of acute lymphoblastic leukemia (IRR, 1.46; 95% CI, 1.42-1.51) compared to non-Hispanic Whites, and the increased risk was strongest at ages 10 through 23 years. Substantial decreased risk across many tumor types was also observed for Asian/Pacific Islanders and American Indian/Alaska Natives. CONCLUSIONS: Examination of incidence rates for pediatric cancers by narrow age groups may provide insights regarding etiological differences in subgroups. Additionally, variation in age-specific incidence rates by race and ethnicity may enable hypothesis generation on drivers of disparities observed.

Factors predicting early mortality after new diagnosis of myelodysplastic syndrome: A population-based study.

OBJECTIVE: Little prospective data regarding factors determining patient outcomes in myelodysplastic syndromes (MDS) are available. To establish features of early mortality in MDS, we compare characteristics of patients dying within 1 year of diagnosis with those surviving longer. METHODS: We prospectively enrolled adults with a new MDS diagnosis in a population-based case-control study. Logistic regression was used to calculate odds ratios and 95% confidence intervals for potential predictors of early mortality. Subgroup analyses were conducted within the following groups: high-/very-high-risk IPSS-R; very-low-/low-/intermediate-risk IPSS-R; treated patients; and supportive care only patients. RESULTS: We observed early mortality in those with abnormal cytogenetics (OR: 3.36, 95% CI: 1.52-7.46), three or greater cytogenetic abnormalities (OR: 3.48, 95% CI: 1.51-7.99), treatment at a community medical center (versus academic) (OR: 2.55, 95% CI: 1.18-5.47), and with 2-3 concurrent medical comorbidities (OR: 2.14, 95% CI: 1.08-4.22). Similarly, in subgroup analyses, abnormal cytogenetics remained the main predictor of early mortality. CONCLUSION: Complex cytogenetics and prognostic risk category have been associated with early mortality without intervention. Our data confirm these associations in a large, prospectively followed cohort and highlight the significance of cytogenetic abnormalities and complexity regardless of IPSS-R risk categorization or treatment.

Family history of cancer and risk of pediatric and adolescent Hodgkin lymphoma: A Children's Oncology Group study.

Family history of lymphoid neoplasm (LN) is a strong and consistently observed Hodgkin lymphoma (HL) risk factor, although it has been only marginally examined in pediatric/adolescent patients. Here, healthy control children identified by random digit dialing were matched on sex, race/ethnicity and age to HL cases diagnosed at 0-14 years at Children's Oncology Group institutions in 1989-2003. Detailed histories were captured by structured telephone interviews with parents of 517 cases and 783 controls. Epstein-Barr virus (EBV) RNA detection was performed for 355 available case tumors. Two analytic strategies were applied to estimate associations between family cancer history and pediatric/adolescent HL. In a standard case-control approach, multivariate conditional logistic regression was used to calculate odds ratios and 95% confidence intervals (CIs). In a reconstructed cohort approach, each relative was included as a separate observation, and multivariate proportional hazards regression was used to produce hazard ratios (HRs) and 95% CIs. Using the latter, pediatric/adolescent HL was associated with a positive family history (HR = 1.20, 95% CI: 1.06-1.36), particularly early-onset cancers (HR = 1.30, 95% CI: 1.06-1.59) and those in the paternal lineage (HR = 1.38, 95% CI: 1.16-1.65), with a suggested association for LN in first-degree relatives (HR = 3.61, 95% CI: 0.87-15.01). There were no discernable patterns for EBV+ versus EBV- HL. The clustering of LN within pedigrees may signal shared genetic susceptibility or common environmental exposures. Heritable genetic risk variants have only recently begun to be discovered, however. These results are consistent with other studies and provide a compelling rationale for family-based studies to garner information about genetic susceptibility to HL.

Cesarean Delivery and Risk of Infant Leukemia: A Report from the Children's Oncology Group.

Background: Studies have reported increased risks of pediatric acute lymphoblastic leukemia (ALL) among children born by cesarean delivery (CD). However, no previous study has examined the impact of CD on risk of infant leukemia specifically.Methods: In this study, 443 infants diagnosed with acute leukemia, including both ALL and acute myelogenous leukemia (AML), were identified at Children's Oncology Group institutions between January 1996 and December 2006; 324 controls frequency matched by year of birth were identified though random digit dialing and random selection from U.S. birth registries. Using interview data and, for a subset of participants, medical record data, we analyzed CD overall and by indications that likely resulted in pre-labor CD (PLCD) or emergency CD (ECD). Odds ratios (ORs) and 95% confidence intervals (CIs) for risk of ALL and AML were estimated using multivariable unconditional logistic regression models, adjusted for year of birth, birth weight, and maternal race.Results: We observed an increased point estimate for the association between CD and ALL (OR, 1.52 and 95% CI, 1.02-2.25). We did not observe an association between CD and AML (OR, 1.02 and 95% CI, 0.64-1.62). In analyses of indication for CD, we observed elevated effect estimates for the associations of both PLCD and ECD and infant ALL.Conclusions: Our analysis suggests an increased risk of infant ALL following CD, including both PLCD and ECD. Altered microbiota colonization may be involved in development of leukemia in infants, but clear biological mechanisms have yet to be determined.Impact: This study provides the first in-depth examination of CD and infant leukemia. Cancer Epidemiol Biomarkers Prev; 27(4); 473-8. ©2018 AACR.