Abstract 5521: Development of a web-based patient registry and DNA repository for pediatric cancer research in individuals with neurofibromatosis type 1

Individuals with hereditary cancer syndromes represent unique study populations to elucidate the genetic, environmental, and clinical factors that influence cancer development and outcome. In this regard, research leveraging these populations has led to landmark discoveries that have advanced our understanding of cancer pathogenesis and prognosis. Neurofibromatosis type 1 (NF1) is one of the most common hereditary cancer syndromes, in which affected individuals are at risk for the development of several benign and malignant cancers. Despite the high frequency of tumorigenesis in this population, factors that predict tumor development and outcomes are poorly defined. To facilitate progress in this area, we have launched the NF1 Patient Registry Initiative (NPRI) and the NF1 Genome Project. The NPRI is a web-based patient-driven registry. Any individual with a NF1 diagnosis is eligible to participate. Participants provide contact information and complete a 30-45 minute questionnaire that captures demographic data, medical history, social history, and inquires whether they are interested in participating in future research studies and providing biological samples. Yearly reminders are sent requesting that participants update their information to allow for longitudinal study of outcomes in this population. From 5/17/2011-11/1/2011, 100 participants have provided contact information, of which 80% have completed the questionnaire. To date, participants include residents of 28 U.S. states and 11 countries spanning 6 continents. The mean age of the participants is 30 years (range 1-77 years), where fifty eight percent are female and 84% are white (race). Approximately half of all participants reported a family history of NF1 (46%). Fourteen pediatric brain cancers (diagnosed <20 years) were reported with a mean diagnosis age of 4 years (range 1-10 years), fifty percent of whom are female. Ninety percent of participants indicated their willingness to be contacted in the future and to provide biological samples for research. The NF1 Genome Project is an initiative developed to collect genomic DNA samples from individuals with NF1 for genome-wide association studies (GWAS). Based on encouraging preliminary GWAS data, future sequencing-based investigations are planned to identify genetic risk modifiers of pediatric tumor susceptibility. To date, a total of 156 participants have provided DNA samples and clinical data. Together, the NPRI and NF1 Genome Project provide unprecedented and viable mechanisms for assembling patients with rare diseases from across the world to discover genomic and non-genomic factors that influence cancer development and progression in a model cancer predisposition syndrome. The insights gained from these studies will not only benefit individuals with NF1, but also serve as foundations for the study of other rare tumor syndromes.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5521. doi:1538-7445.AM2012-5521

Birth characteristics and childhood carcinomas

Background:

Carcinomas in children are rare and have not been well studied.

Methods:

We conducted a population-based case–control study and examined associations between birth characteristics and childhood carcinomas diagnosed from 28 days to 14 years during 1980–2004 using pooled data from five states (NY, WA, MN, TX, and CA) that linked their birth and cancer registries. The pooled data set contained 57 966 controls and 475 carcinoma cases, including 159 thyroid and 126 malignant melanoma cases. We used unconditional logistic regression to calculate odds ratios (ORs) and 95% confidence intervals (CIs).

Results:

White compared with ‘other’ race was positively associated with melanoma (OR=3.22, 95% CI 1.33–8.33). Older maternal age increased the risk for melanoma (OR_{per 5-year age increase}=1.20, 95% CI 1.00–1.44), whereas paternal age increased the risk for any carcinoma (OR=1.10_{per 5-year age increase}, 95% CI 1.01–1.20) and thyroid carcinoma (OR_{per 5-year age increase}=1.16, 95% CI 1.01–1.33). Gestational age <37 vs 37–42 weeks increased the risk for thyroid carcinoma (OR=1.87, 95% CI 1.07–3.27). Plurality, birth weight, and birth order were not significantly associated with childhood carcinomas.

Conclusion:

This exploratory study indicates that some birth characteristics including older parental age and low gestational age may be related to childhood carcinoma aetiology.

Characterization of the elemental composition of newborn blood spots using sector-field inductively coupled plasma-mass spectrometry

We developed extraction and analysis protocols for element detection in neonatal blood spots (NBSs) using sector-field inductively coupled plasma-mass spectrometry (SF-ICP-MS). A 5% (v/v) nitric acid element extraction protocol was optimized and used to simultaneously measure 28 elements in NBS card filter paper and 150 NBSs. NBS element concentrations were corrected for filter paper background contributions estimated from measurements in samples obtained from either unspotted or spotted NBS cards. A lower 95% uncertainty limit (UL) that accounted for ICP-MS method, filter paper element concentration, and element recovery uncertainties was calculated by standard methods for each individual's NBS element concentration. Filter paper median element levels were highly variable within and between lots for most elements. After accounting for measurement uncertainties, 11 elements (Ca, Cs, Cu, Fe, K, Mg, Na, P, Rb, S, and Zn) had lower 95% ULs>0 ng/spot with estimated concentrations ranging from 0.05 to >50,000 ng/spot in ≥50% of NBS samples in both correction methods. In a NBS sample minority, Li, Cd, Cs, Cr, Ni, Mo, and Pb had estimated concentrations ≥20-fold higher than the respective median level. Taking measurement uncertainties into account, this assay could be used for semiquantitative newborn blood element measurement and for the detection of individuals exposed to supraphysiologic levels of some trace elements. Adequate control of filter paper element contributions remains the primary obstacle to fully quantitative element measurement in newborn blood using NBSs.

Maternal exposure to household chemicals and risk of infant leukemia: a report from the Children's Oncology Group

OBJECTIVE

Utilizing data from the largest study to date, we examined associations between maternal preconception/prenatal exposure to household chemicals and infant acute leukemia.

METHODS

We present data from a Children's Oncology Group case-control study of 443 infants (<1 year of age) diagnosed with acute leukemia [including acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML)] between 1996 and 2006 and 324 population controls. Mothers recalled household chemical use 1 month before and throughout pregnancy. We used unconditional logistic regression adjusted for birth year, maternal age, and race/ethnicity to calculate odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

We did not find evidence for an association between infant leukemia and eight of nine chemical categories. However, exposure to petroleum products during pregnancy was associated with AML (OR = 2.54; 95% CI:1.40-4.62) and leukemia without mixed lineage leukemia (MLL) gene rearrangements ("MLL-") (OR = 2.69; 95% CI: 1.47-4.93). No associations were observed for exposure in the month before pregnancy.

CONCLUSIONS

Gestational exposure to petroleum products was associated with infant leukemia, particularly AML, and MLL- cases. Benzene is implicated as a potential carcinogen within this exposure category, but a clear biological mechanism has yet to be elucidated.

Abstract 812: Maternal folic acid supplementation and risk of medulloblastoma in offspring

Background: Epidemiological studies can give important insights into factors that modulate disease risk. However, the inherent limitations of observational studies make causal relationships difficult to infer. For example, several case-control studies have indicated that prenatal vitamins may protect against childhood brain tumors, including medulloblastoma, and folic acid (FA) is speculated to be the modulating factor. Using a murine model, we are testing whether low maternal dietary FA during the peri-gestational period increases medulloblastoma risk in offspring. We are using a well-defined transgenic mouse model of Gorlin syndrome, which is characterized by an autosomal dominant mutation in the PTCH1 gene. Heterozygous C57BL/6 strain Ptc1+/− mice have a medulloblastoma incidence of ∼40% at one year, making this transgenic model highly suitable for childhood brain cancer etiologic studies.

Methods. A total of 126 female wild-type C57BL/6 mice were randomized to one of three amino acid defined FA diets: 1) 0.3 mg/kg (low), 2) 2.0 mg/kg (control), and 3) 8.0 mg/kg (high), one month prior to mating with Ptc1+/− C57BL/6 males and maintained on their respective diets until weaning of their pups. Red blood cell (RBC) folate measurements were obtained from the dams at weaning and their association with the assigned dietary FA dose was determined using one-way ANOVA. The offspring have been genotyped and weaned heterozygotes are being followed for tumor development for one year. Interim hazard ratios (HRs) and 95% confidence intervals (CIs) were computed using Cox proportional hazards regression to examine the association between the assigned maternal dietary FA dose and offspring tumor incidence.

Results. In a total of 381 offspring, the overall Ptc1+/− genotype frequency is similar to previous reports with no significant differences between dietary groups (low: 40%, control: 40%, high: 42%). RBC folate concentrations in the dams at weaning increased significantly with increasing FA dose (p&lt;0.0001). Ptc1+/− offspring from each of the dietary groups have been followed for a mean of ∼6 months. To date, 25%, 35%, and 37% of Ptc1+/− offspring have developed tumors in the low, control, and high FA groups, respectively.Compared to the control group, the hazard for tumor development was non-significantly decreased in offspring in the low FA group (HR=0.7; 95% CI 0.3-1.4) and similar in the high FA group (HR=1.0; 95% CI 0.5-1.8).

Conclusions. In contrast to our hypothesis, these preliminary results indicate that higher doses of maternal dietary FA may increase offspring brain tumor incidence. We speculate that higher dietary FA levels during the peri-gestational period may influence brain tumor progression in mice predisposed to tumor development. The implications of these findings with respect to human populations will be discussed. Supported by R03CA141440, T32CA099936, and the Children's Cancer Research Fund, Minneapolis, MN.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 812. doi:10.1158/1538-7445.AM2011-812

Maternal dietary patterns during early pregnancy and the odds of childhood germ cell tumors: A Children's Oncology Group study

Maternal diet during pregnancy may be associated with cancer in offspring. Intake of individual foods, as well as dietary patterns, can be used when examining these relations. Here, the authors examined associations between maternal dietary intake patterns and pediatric germ cell tumors (GCTs) using principal components analysis and logistic regression. Mothers of 222 GCT cases aged less than 15 years who were diagnosed at a Children's Oncology Group institution between 1993 and 2001 and those of 336 frequency-matched controls completed a self-administered food frequency questionnaire of diet during early pregnancy. Four dietary patterns were identified: "Western," "fruits and vegetables," "protein," and "healthful." With adjustment for birth weight, parity, and vitamin use, the fruits and vegetables pattern was significantly associated with a lower odds for GCTs (odds ratio (OR) = 0.83, 95% confidence interval (CI): 0.69, 0.99; 2 sided). Upon stratification, the fruits and vegetables pattern was significantly associated with a lower odds in males (OR = 0.66, 95% CI: 0.47, 0.92) but not females (OR = 0.91, 95% CI: 0.72, 1.14). A quantitative assessment of assumed nondifferential reporting error indicated no notable deviations from unadjusted odds ratio estimates. Results of this exploratory analysis suggest that maternal prenatal dietary patterns could be considered in future studies of GCTs in offspring.

Birth order and risk of childhood cancer: a pooled analysis from five US States

The causes of childhood cancers are largely unknown. Birth order has been used as a proxy for prenatal and postnatal exposures, such as frequency of infections and in utero hormone exposures. We investigated the association between birth order and childhood cancers in a pooled case-control dataset. The subjects were drawn from population-based registries of cancers and births in California, Minnesota, New York, Texas and Washington. We included 17,672 cases <15 years of age who were diagnosed from 1980 to 2004 and 57,966 randomly selected controls born 1970-2004, excluding children with Down syndrome. We calculated odds ratios and 95% confidence intervals using logistic regression, adjusted for sex, birth year, maternal race, maternal age, multiple birth, gestational age and birth weight. Overall, we found an inverse relationship between childhood cancer risk and birth order. For children in the fourth or higher birth order category compared to first-born children, the adjusted OR was 0.87 (95% CI: 0.81, 0.93) for all cancers combined. When we examined risks by cancer type, a decreasing risk with increasing birth order was seen in the central nervous system tumors, neuroblastoma, bilateral retinoblastoma, Wilms tumor and rhabdomyosarcoma. We observed increased risks with increasing birth order for acute myeloid leukemia but a slight decrease in risk for acute lymphoid leukemia. These risk estimates were based on a very large sample size, which allowed us to examine rare cancer types with greater statistical power than in most previous studies, however the biologic mechanisms remain to be elucidated.

Childhood cancer in relation to parental race and ethnicity: a 5-state pooled analysis

BACKGROUND

Children of different racial/ethnic backgrounds have varying risks of cancer. However, to the authors' knowledge, few studies to date have examined cancer occurrence in children of mixed ancestry.

METHODS

This population-based case-control study examined cancer among children aged <15 years using linked cancer and birth registry data from 5 US states from 1978 through 2004. Data were available for 13,249 cancer cases and 36,996 controls selected from birth records. Parental race/ethnicity was determined from birth records. Logistic regression analysis was used to examine the association of cancer with different racial/ethnic groups.

RESULTS

Compared with whites, blacks had a 28% decreased risk of cancer (odds ratio [OR], 0.72; 95% confidence interval [95% CI], 0.65-0.80), whereas both Asians and Hispanics had an approximate 15% decrease. Children of mixed white/black ancestry also were found to be at decreased risk (OR, 0.71; 95% CI, 0.56-0.90), but estimates for mixed white/Asian and white/Hispanic children did not differ from those of whites. Compared with whites: 1) black and mixed white/black children had decreased ORs for acute lymphoblastic leukemia (OR, 0.39 [95% CI, 0.31-0.49] and OR, 0.58 [95% CI, 0.37-0.91], respectively); 2) Asian and mixed white/Asian children had decreased ORs for brain tumors (OR, 0.51 [95% CI, 0.39-0.68] and OR, 0.79 [95% CI, 0.54-1.16], respectively); and 3) Hispanic and mixed white/Hispanic children had decreased ORs for neuroblastoma (OR, 0.51 [95% CI, 0.42-0.61] and OR, 0.67 [95% CI, 0.50-0.90], respectively).

CONCLUSIONS

Children of mixed ancestry tend to have disease risks that are more similar to those of racial/ethnic minority children than the white majority group. This tendency may help formulate etiologic studies designed to study possible genetic and environmental differences more directly.

Infant leukemia and congenital abnormalities: a Children's Oncology Group study

BACKGROUND

Leukemia in infants is rare and has not been well studied apart from leukemia in older children. Differences in survival and the molecular characteristics of leukemia in infants versus older children suggest a distinct etiology, likely involving prenatal factors.

PROCEDURE

We examined the association between eight categories of maternally reported congenital abnormalities (CAs) (cleft lip or palate, spina bifida or other spinal defect, large or multiple birthmarks, other chromosomal abnormalities, small head or microcephaly, rib abnormalities, urogenital abnormalities, and other) and infant leukemia in a case-control study. The study included 443 cases diagnosed at <1 year of age at a Children's Oncology Group Institution in the United States or Canada from 1996 to 2006 and 324 controls. Controls were recruited from the cases' geographic area either by random digit dialing (1999-2002) or through birth certificates (2003-2008) and were frequency-matched to cases on birth year. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated by unconditional logistic regression after adjustment for birth year and a measure of follow-up time to account for differences in the CA observation period.

RESULTS

No statistically significant associations were observed between infant leukemia and any CA (OR = 1.2; 95% CI: 0.8-1.9), birthmarks (OR = 1.4; 95% CI: 0.7-2.5), urogenital abnormalities (OR = 0.7; 95% CI: 0.2-2.0), or other CA (OR = 1.4; 95% CI: 0.7-2.8). Results were similar for acute lymphoblastic and myeloid leukemia cases. Fewer than five subjects were in the remaining CA categories precluding analysis.

CONCLUSIONS

Overall, we did not find evidence to support an association between CAs and infant leukemia.

Parental educational attainment as an indicator of socioeconomic status and risk of childhood cancers

Background:

Little has been reported on socioeconomic (SES) patterns of risk for most forms of childhood cancer.

Methods:

Population-based case–control data from epidemiological studies of childhood cancer conducted in five US states were pooled and associations of maternal, paternal and household educational attainment with childhood cancers were analysed. Odds ratios (ORs) and 95% confidence intervals were estimated using logistic regression, controlling for confounders.

Results:

Although there was no association with parental education for the majority of cancers evaluated, there was an indication of a positive association with lower education for Hodgkin's and Burkitt's lymphoma and Wilm's tumour, with the ORs ranging from 1.5 to >3.0 times that of more educated parents. A possible protective effect was seen for lower parental education and astrocytoma and hepatoblastoma, with ORs reduced by 30 to 40%.

Conclusions:

These study results should be viewed as exploratory because of the broad nature of the SES assessment, but they give some indication that childhood cancer studies might benefit from a more thorough assessment of SES.

Postoutbreak disinfection of mobile equipment

Current control strategies for avian influenza virus, exotic Newcastle disease, and other highly contagious poultry diseases include surveillance, quarantine, depopulation, disposal, and decontamination. Skid steer loaders and other mobile equipment are extensively used during depopulation and disposal. Movement of contaminated equipment has been implicated in the spread of disease in previous outbreaks. One approach to equipment decontamination is to power wash the equipment, treat with a liquid disinfectant, change any removable filters, and let it sit idle for several days. In this project, multiple disinfectant strategies were individually evaluated for their effectiveness at inactivating Newcastle disease virus (NDV) on mechanical equipment seeded with the virus. A small gasoline engine was used to simulate typical mechanical equipment. A high titer of LaSota strain, NDV was applied and dried onto a series of metal coupons. The coupons were then placed on both interior and exterior surfaces of the engine. Liquid disinfectants that had been effective in the laboratory were not as effective at disinfecting the engine under field conditions. Indirect thermal fog showed a decrease in overall virus titer or strength. Direct thermal fog was more effective than liquid spray application or indirect thermal fog application.

Comparison of water-based foam and inert-gas mass emergency depopulation methods

Current control strategies for avian influenza (AI) and other highly contagious poultry diseases include surveillance, quarantine, depopulation, disposal, and decontamination. Selection of the best method of emergency mass depopulation involves maximizing human health and safety while minimizing disease spread and animal welfare concerns. Proper selection must ensure that the method is compatible with the species, age, housing type, and disposal options. No one single method is appropriate for all situations. Gassing is one of the accepted methods for euthanatizing poultry. Whole-house, partial-house, or containerized gassing procedures are currently used. The use of water-based foam was developed for emergency mass depopulation and was conditionally approved by the United States Department of Agriculture in 2006. Research has been done comparing these different methods; parameters such as time to brain death, consistency of time to brain death, and pretreatment and posttreatment corticosterone stress levels were considered. In Europe, the use of foam with carbon dioxide is preferred over conventional water-based foam. A recent experiment comparing CO2 gas, foam with CO2 gas, and foam without CO2 gas depopulation methods was conducted with the use of electroencephalometry results. Foam was as consistent as CO2 gassing and more consistent than argon-CO2 gassing. There were no statistically significant differences between foam methods.

Abstract 913: 5,10-Methylenetetrahydrofolate reductase C677T allele frequency and childhood leukemia incidence in predominantly European ancestry countries

5,10-Methylentetrahydrofolate reductase (MTHFR) single nucleotide polymorphisms (SNPs) have been intensely studied as cancer susceptibility alleles. For childhood leukemia, data have indicated that the most commonly studied MTHFR SNP, C677T, is associated with a slightly reduced risk of acute lymphoblastic leukemia (ALL). Both childhood leukemia incidence and MTHFR allele frequencies show variation worldwide. Our objective was to conduct an ecologic study to determine whether the MTHFR C677T allele frequency and childhood leukemia incidence are associated. We used cancer incidence data collected by the International Agency for Cancer Research from 22 registries that captured 19,025 leukemia cases diagnosed between the ages of 0 and 14 years from the United States, Canada, Australia, and 18 European countries; data were restricted to registries with majority European ancestry populations in order to minimize confounding by ancestry. MTHFR allele frequencies were gathered from the literature to match as closely as possible the registry populations. We modeled the association between childhood leukemia incidence and MTHFR C677T allele frequency using Poisson regression to calculate rate ratios (RRs) and 95% confidence intervals (CIs). Estimates of the minor C677T allele frequency ranged from 24% in Finland to 44% in Italy. There was a weak inverse correlation between leukemia incidence and MTHFR C677T allele frequency (r=0.19), that was stronger for ALL (r=0.30). Acute nonlymphoblastic leukemia (ANLL) incidence was positively correlated with MTHFR C677T allele frequency (r=0.36). Poisson regression results from linear models showed that the incidence of childhood leukemia decreased by 5% (95% CI 3%-6%) for every 5% increase in the C677T allele frequency. A similar pattern was observed for ALL with a RR of 0.93 (95% CI=0.92-0.95) but not acute non-lymphoblastic leukemia (ANLL) (RR=1.04, 95% CI=1.00-1.07). The significant inverse associations between the C677T allele frequency and leukemia and ALL incidence were specific to incidence rates for children diagnosed &lt;10 years. These results are consistent with the results of case-control studies of the association between childhood leukemia and MTHFR allele frequency suggesting a modest risk reduction in association with the C677T allele. The strengths and limitations of ecological vs. case control study designs will be discussed in the context of these results to provide insight into the causal relationship between the MTHFR minor allele frequency and childhood leukemia risk.

This research was supported by NIH grant T32 CA099936.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 913.

Pediatric germ cell tumors and maternal vitamin supplementation: a Children's Oncology Group study

Maternal vitamin supplementation has been linked to a reduced risk of several pediatric malignancies. We examined this relationship in a study of childhood germ cell tumors (GCT). Subjects included 278 GCT cases diagnosed <15 years during 1993 to 2001 at a United States or Canadian Children's Oncology Group Institution and 423 controls that were ascertained through random digit dialing matched to cases on sex, and age within 1 year. Unconditional logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (CI) for the association between GCTs and maternal vitamin use at several time points during and around pregnancy. In models controlling for the child's age, sex, household income, and maternal education, any maternal vitamin use during the 6 months before conception through nursing was associated with a nonsignificant reduced risk of GCTs (OR, 0.7; 95% CI, 0.4-1.2). Inverse associations were observed for both extragonadal (OR, 0.8; 95% CI, 0.4-1.6) and gonadal (OR, 0.6; 95% CI, 0.3-1.1) tumors, and for dysgerminoma/seminoma (OR, 0.6; 95% CI, 0.2-1.3) and teratoma (OR, 0.5; 95% CI, 0.2-0.9) but not yolk sac tumors (OR, 1.1; 95% CI, 0.5-2.3). No consistent patterns were found with respect to vitamin use during the periconceptional period (6 months before pregnancy and first trimester) or first trimester specifically. In conclusion, although our study suggests that maternal vitamin supplementation may reduce the risk or pediatric GCTs in the offspring, the small study size and limitations inherent to observational studies must be considered when interpreting these results.

Parental age and risk of childhood cancer: a pooled analysis

BACKGROUND

Few risk factors for childhood cancer are well-established. We investigated whether advancing parental age increases childhood cancer risk.

METHODS

We assessed the relationship between parental age and childhood cancer in a case-control study using pooled population-based data. Our pooling was based on linked cancer and birth registry records from New York, Washington, Minnesota, Texas, and California. Subjects included 17,672 cancer cases diagnosed at ages 0-14 years during 1980-2004 and 57,966 controls born during 1970-2004. Individuals with Down syndrome were excluded. Odds ratios and 95% confidence intervals were calculated by logistic regression for the association between parental age and childhood cancer after adjustment for sex, birth weight, gestational age, birth order, plurality, maternal race, birth year, and state.

RESULTS

Positive linear trends per 5-year maternal age increase were observed for childhood cancers overall (odds ratio = 1.08 [95% confidence interval = 1.06-1.10]) and 7 of the 10 most frequent diagnostic groups: leukemia (1.08 [1.05-1.11]), lymphoma (1.06 [1.01-1.12]), central nervous system tumors (1.07 [1.03-1.10]), neuroblastoma (1.09 [1.04-1.15]), Wilms' tumor (1.16 [1.09-1.22]), bone tumors (1.10 [1.00-1.20]), and soft tissue sarcomas (1.10 [1.04-1.17]). No maternal age effect was noted for retinoblastoma, germ cell tumors, or hepatoblastoma. Paternal age was not independently associated with most childhood cancers after adjustment for maternal age.

CONCLUSIONS

Our results suggest that older maternal age increases risk for most common childhood cancers. Investigation into possible mechanisms for this association is warranted.

Cancer risk among children with very low birth weights

OBJECTIVE

The risk of hepatoblastoma is strongly increased among children with very low birth weight (<1500 g). Because data on very low birth weight and other childhood cancers are sparse, we examined the risk of malignancy with very low birth weight in a large data set.

METHODS

We combined case-control data sets created by linking the cancer and birth registries of California, Minnesota, New York, Texas, and Washington states, which included 17672 children diagnosed as having cancer at 0 to 14 years of age and 57966 randomly selected control subjects. Unconditional logistic regression analysis was used to examine the association of cancer with very low birth weight and moderately low birth weight (1500-1999 g and 2000-2499 g, respectively), compared with moderate/high birth weight (>or=2500 g), with adjustment for gender, gestational age, birth order, plurality, maternal age, maternal race, state, and year of birth.

RESULTS

Most childhood cancers were not associated with low birth weights. However, retinoblastomas and gliomas other than astrocytomas and ependymomas were possibly associated with very low birth weight. The risk of other gliomas was also increased among children weighing 1500 to 1999 g at birth.

CONCLUSIONS

These data suggested no association between most cancers and very low birth weight, with the exception of the known association of hepatoblastoma and possibly moderately increased risks of other gliomas and retinoblastoma, which may warrant confirmation.

Childhood cancer among twins and higher order multiples

Although several studies have found no change or a decreased risk of childhood cancer in twins, few have controlled for potential confounders such as birth weight. We examined the association of birth plurality and childhood cancer in pooled data from five U.S. states (California, Minnesota, New York, Texas, and Washington) using linked birth-cancer registry data. The data, excluding children with Down syndrome or who died before 28 days of life, included 17,672 cases diagnosed from 1980 to 2004 at ages 28 days to 14 years and 57,966 controls with all cases and controls born from 1970 to 2004. Analyses were restricted to children weighing Collapse

Key Words

• childhood cancer
• twins
• multiple birth
• case-control
• pooled data

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MESH Headings

• Adolescent
• Case-Control Studies
• Child
• Child, Preschool
• Diseases in Twins/epidemiology
• Female
• Humans
• Infant
• Infant, Newborn
• Kidney Neoplasms/epidemiology
• Logistic Models
• Male
• Multiple Birth Offspring
• Neoplasms/epidemiology
• Registries
• Retinal Neoplasms/epidemiology
• Retinoblastoma/epidemiology
• Risk Factors
• United States/epidemiology
• Wilms Tumor/epidemiology

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Grants

• R01CA717450 NCI NIH HHS
• R01 CA092670-04 NCI NIH HHS
• U58 DP000783 NCCDPHP CDC HHS
• R01CA92670 NCI NIH HHS
• R01 CA092670 NCI NIH HHS
• T32 CA099936-04 NCI NIH HHS
• N01 CN005230 NCI NIH HHS
• R01 CA071745-04 NCI NIH HHS
• T32 CA099936 NCI NIH HHS

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Childhood cancer in the offspring born in 1921-1984 to US radiologic technologists

We examined the risk of childhood cancer (<20 years) among 105 950 offspring born in 1921-1984 to US radiologic technologist (USRT) cohort members. Parental occupational in utero and preconception ionising radiation (IR) testis or ovary doses were estimated from work history data, badge dose data, and literature doses (the latter doses before 1960). Female and male RTs reported a total of 111 and 34 haematopoietic malignancies and 115 and 34 solid tumours, respectively, in their offspring. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated using Cox proportional hazards regression. Leukaemia (n=63) and solid tumours (n=115) in offspring were not associated with maternal in utero or preconception radiation exposure. Risks for lymphoma (n=44) in those with estimated doses of <0.2, 0.2-1.0, and >1.0 mGy vs no exposure were non-significantly elevated with HRs of 2.3, 1.8, and 2.7. Paternal preconception exposure to estimated cumulative doses above the 95th percentile (82 mGy, n=6 cases) was associated with a non-significant risk of childhood cancer of 1.8 (95% CI 0.7-4.6). In conclusion, we found no convincing evidence of an increased risk of childhood cancer in the offspring of RTs in association with parental occupational radiation exposure.

Birth characteristics and Wilms tumor in Minnesota

Wilms tumor (WT) is a childhood kidney cancer with the highest rate of occurrence before the age of 2. Since it is rare, previous research has been limited and few risk factors have been established. We used a case-cohort design to examine the influence of birth characteristics on occurrence of WT in Minnesota. A total of 2,188 cases of cancer diagnosed in children aged 28 days to 14 years from 1988 to 2004 were identified using the Minnesota Cancer Surveillance System (MCSS). For each case, 4 children were randomly selected from Minnesota birth records during 1976-2004, frequency matched on birth year. Thus, a total of 8,752 children comprised the subcohort for the study, who in this analysis, served as comparison to the 138 cases of WT. Study variables included parental demographics, maternal pregnancy history and conditions and health and conditions of the child at birth. Associations with WT were assessed using hazard ratios (HR) and 95% confidence intervals (CI) calculated from stratified Cox regression models. We found an increased risk of WT for children who were large for gestational age compared to those average for gestational age and for children with congenital abnormalities. There was also an increased risk for children with a birth weight > 4,000 g compared to those with a birth weight between 2,500 and 4,000 g. All other factors examined showed no association with WT. This study contributes to the mounting evidence that children with large size at birth have an increased risk of WT.

Parental and infant characteristics and childhood leukemia in Minnesota

BACKGROUND

Leukemia is the most common childhood cancer. With the exception of Down syndrome, prenatal radiation exposure, and higher birth weight, particularly for acute lymphoid leukemia (ALL), few risk factors have been firmly established. Translocations present in neonatal blood spots and the young age peak of diagnosis suggest that early-life factors are involved in childhood leukemia etiology.

METHODS

We investigated the association between birth characteristics and childhood leukemia through linkage of the Minnesota birth and cancer registries using a case-cohort study design. Cases included 560 children with ALL and 87 with acute myeloid leukemia (AML) diagnoses from 28 days to 14 years. The comparison group was comprised of 8,750 individuals selected through random sampling of the birth cohort from 1976-2004. Cox proportional hazards regression specific for case-cohort studies was used to compute hazard ratios (HR) and 95% confidence intervals (CIs).

RESULTS

Male sex (HR = 1.41, 95% CI 1.16-1.70), white race (HR = 2.32, 95% CI 1.13-4.76), and maternal birth interval > or = 3 years (HR = 1.31, 95% CI 1.01-1.70) increased ALL risk, while maternal age increased AML risk (HR = 1.21/5 year age increase, 95% CI 1.0-1.47). Higher birth weights (>3798 grams) (HRALL = 1.46, 1.08-1.98; HRAML = 1.97, 95% CI 1.07-3.65), and one minute Apgar scores < or = 7 (HRALL = 1.30, 95% CI 1.05-1.61; HRAML = 1.62, 95% CI 1.01-2.60) increased risk for both types of leukemia. Sex was not a significant modifier of the association between ALL and other covariates, with the exception of maternal education.

CONCLUSION

We confirmed known risk factors for ALL: male sex, high birth weight, and white race. We have also provided data that supports an increased risk for AML following higher birth weights, and demonstrated an association with low Apgar scores.

Childhood cancer and birthmarks in the Collaborative Perinatal Project

OBJECTIVE

Three previous retrospective studies noted a positive association between birthmarks and childhood cancer. The objective of this study was to determine whether the incidence of cancer is increased in children with birthmarks relative to those without birthmarks using data from the Collaborative Perinatal Project cohort, a large, prospective study.

METHODS

Our study population comprised 49,503 US children who were born between 1959 and 1968. Birthmarks were documented as definite or suspected during the first year through history or medical examinations and included hemangiomas (port-wine, strawberry, or cavernous), pigmented nevi, lymphangiomas, and café-au-lait spots. The association between birthmarks and childhood cancer was determined using Cox proportional hazards regression.

RESULTS

In the Collaborative Perinatal Project, 2505 individuals had a documented definite or suspected birthmark, including 7 of 47 children who developed cancer. Birthmarks were associated with a significant increase in the risk for cancer. There was a slight attenuation of the risk estimate when cases that were diagnosed in the first year of life were excluded. No specific childhood malignancies were notably affected by birthmarks.

CONCLUSIONS

Although this study was based on a small number of cases, we found birthmarks to be in excess in children who received a diagnosis of cancer using prospective data. These findings provide additional support for the possibility of a shared etiology between birthmarks and childhood cancer that could offer insight into the pathogenesis of pediatric malignancy.