Incidence of childhood leukaemia and non-Hodgkinʼs lymphoma in France: National Registry of Childhood Leukaemia and Lymphoma, 1990–1999

Maintenance Therapy With Interleukin-2 for Childhood AML: Results of ELAM02 Phase III Randomized Trial

Despite significant progress in the treatment of pediatric acute myeloblastic leukemia (AML), relapse remains the commonest cause of death. Randomized ELAM02 trial questioned if maintenance therapy with interleukin-2 (IL2), for 1 year, improves disease-free survival (DFS). Patients aged 0 to 18 years, with newly diagnosed AML (excluding patients with acute promyelocytic leukemia or down syndrome AML) were enrolled. They received 1 course of induction treatment (cytarabine and mitoxantrone) and 3 courses of consolidation treatment (high-dose cytarabine in courses 1 and 3). According to the cytogenetics risk, patients not undergoing hematopoietic stem cell transplantation, still in complete remission (CR) after the third course of consolidation treatment, were eligible for randomization to 1 year of maintenance therapy with monthly courses of IL2 or no maintenance treatment. There were 438 evaluable patients, 154 of whom were randomized to the IL2/no maintenance groups. Relapse occurred in 28 patients from the IL2+ group and 29 patients in the IL2- group. Survival was similar in the 2 groups, with a 4-year DFS of 62% without IL2 and 66% with IL2 (P = 0.75). In the CBF population, 4-year DFS was 55% without IL2 and 78% with IL2 (P = 0.07). No deaths from toxicity or excess of serious adverse events related to IL2 treatment were recorded. Prolonged IL2 for maintenance therapy after intensive chemotherapy is feasible and safe in pediatric AML patients in their first CR. Such treatment did not improve DFS in this study, but a positive trend was observed in favor of IL2 maintenance therapy among core binding factor acute myeloblastic leukemia.

Spatial and temporal variations of childhood cancers: Literature review and contribution of the French national registry

BACKGROUND

Significant increases in childhood cancer incidence since the 1970s have been consistently reported worldwide, but the persistence of the increase on recent periods is discussed. No conclusion can be drawn concerning the spatial variations of childhood cancer, either. This study is an in-depth investigation of the spatial and temporal variations of childhood cancer in France. An extensive review of all the studies published since 2000 on those issues is provided.

METHODS

The study included 25 877 cases of childhood cancer registered nationwide over 2000-2014. The spatial heterogeneity (overdispersion, autocorrelation, overall heterogeneity) was tested, on two geographic scales, and two spatial scan methods were used to detect clusters of cases. The annual average percent change (AAPC) in incidence rate was estimated with Poisson regression models, and joinpoint analyses were considered.

RESULTS

Glioma and non-Hodgkin lymphoma cases exhibited some spatial heterogeneity and two large clusters were detected. Overall, the incidence rate of childhood cancer was stable over 2000-2014 (AAPC = -0.1% [-0.3%; 0.2%]). A log-linear positive trend was significantly evidenced for gliomas other than pilocytic astrocytomas (AAPC = 1.8% [0.9%; 2.7%]), with some suggestion of a leveling-off at the end of the period, while Burkitt lymphoma and germ cell tumor incidence rates decreased (AAPC = -2.2% [-3.8%; -0.5%] and AAPC = -1.9% [-3.4%; -0.3%], respectively). No spatial heterogeneity or significant time variation was evidenced for other cancers.

CONCLUSION

Several types of childhood cancer displayed some spatial heterogeneity and two large clusters were detected, the origins of which are to be investigated and might include differences in case ascertainment. Overall, the results do not support a sustained increase in incidence rates of childhood cancer in recent years.

Pesticides and Child's Health in France

PURPOSE OF REVIEW

The use of pesticides is predominant in agriculture, inducing environmental contamination, and has been extended to the domestic sphere. In France, > 500 pesticides were authorized for use in 2009; given their various toxicological properties, there are legitimate concerns about the possible consequences for child health. This review summarizes the recent French studies of good quality dealing with pesticides and child health.

RECENT FINDINGS

Three cohorts (mother-child, retrospective) and two case-control studies have been conducted in the last decade. Using various instruments for exposure assessment including biomarkers, they have suggested alterations of subclinical health parameters at birth, increased risk of otitis at age 2, and increased risk of several types of childhood cancer. However, there were no adverse neurodevelopmental outcomes at 6 years of age following prenatal exposure to pesticides. Both agricultural and domestic pesticides might be involved in such adverse health outcomes. Similar studies are lacking in Europe. Studies on fungicides and child health are scarce.

Acute Myeloid Leukemia With Central Nervous System Involvement in Children: Experience From the French Protocol Analysis ELAM02

Central nervous system (CNS) involvement at diagnosis of pediatric acute myeloid leukemia (AML) is not considered as an independent prognostic factor. This study describes the prognostic value of pediatric AML with CNS involvement at diagnosis. Pediatric patients were treated for de novo AML in the French multicenter trial ELAM02. Lumbar puncture was carried out in the first week, and the treatment was adapted to the CNS status. No patient received CNS radiotherapy. The patients were classified into 2 groups: CNS+ and CNS-. Of the 438 patients, 16% (n=70) had CNS involvement at diagnosis, and 29% showed clinical signs. The patients with CNS disease were younger (40% were below 2 y old), had a higher white blood cell count (median of 45 vs. 13 G/L), and had M4 and M5 morphologies. The complete remission rate was similar at 92.8% for CNS+ and 88.5% for CNS-. There was no significant difference between the CNS+ and the CNS- group in overall survival (76% and 71%, respectively) and event-free survival (57% and 52%, respectively). Regarding the occurrence of first relapse, the CNS+ group had a higher combined relapse rate of 26.1% compared with 10% for the CNS- group. The results indicate that CNS involvement at diagnosis of pediatric AML is not an independent prognostic factor. Triple intrathecal chemotherapy combined with high-dose intravenous cytarabine should be the first-line treatment for CNS disease.

Residential Exposure to Natural Background Radiation and Risk of Childhood Acute Leukemia in France, 1990-2009

BACKGROUND

Exposures to high-dose ionizing radiation and high-dose rate ionizing radiation are established risk factors for childhood acute leukemia (AL). The risk of AL following exposure to lower doses due to natural background radiation (NBR) has yet to be conclusively determined.

METHODS

AL cases diagnosed over 1990-2009 (9,056 cases) were identified and their municipality of residence at diagnosis collected by the National Registry of Childhood Cancers. The Geocap study, which included the 2,763 cases in 2002-2007 and 30,000 population controls, was used for complementary analyses. NBR exposures were modeled on a fine scale (36,326 municipalities) based on measurement campaigns and geological data. The power to detect an association between AL and dose to the red bone marrow (RBM) fitting UNSCEAR (United Nations Scientific Committee on the Effects of Atomic Radiation) predictions was 92%, 45% and 99% for exposure to natural gamma radiation, radon and total radiation, respectively.

RESULTS

AL risk, irrespective of subtype and age group, was not associated with the exposure of municipalities to radon or gamma radiation in terms of yearly exposure at age reached, cumulative exposure or RBM dose. There was no confounding effect of census-based socio-demographic indicators, or environmental factors (road traffic, high voltage power lines, vicinity of nuclear plants) related to AL in the Geocap study.

CONCLUSIONS

Our findings do not support the hypothesis that residential exposure to NBR increases the risk of AL, despite the large size of the study, fine scale exposure estimates and wide range of exposures over France. However, our results at the time of diagnosis do not rule out a slight association with gamma radiation at the time of birth, which would be more in line with the recent findings in the UK and Switzerland.

Clinical Impact of Overexpression of FOXP3 and WT1 on Disease Outcome in Egyptian Acute Myeloid Leukemia Patients

Background:

In the last decade, it has become clear that change of gene expression may alter the hematopoietic cell quiescent state and consequently play a major role in leukemogenesis. WT1 is known to be a player in acute myeloid leukemia (AML) and FOXP3 has a crucial role in regulating the immune response.

Objectives:

To evaluate the impact of overexpression of WT1and FOXP3 genes on clinical course in adult and pediatric AML patients in Egypt.

Patients and methods:

Bone marrow and peripheral blood samples were obtained from 97 de novo non M3 AML patients (63 adult and 34 pediatric). Real-time quantitative PCR was used to detect overexpression WT1 and FOXP3 genes. Patient follow up ranged from 0.2 to 39.0 months with a median of 5 months.

Results:

In the pediatric group; WT1 was significantly expressed with a high total leukocyte count median 50X109/L (p=0.018). In the adult group, WT1 had an adverse impact on complete remission induction, disease-free survival and overall survival (p=0.02, p=0.035, p=0.019 respectively). FOXP3 overexpression was associated with FAB subtypes AML M0 +M1 vs. M2, M4+M5 (p =0.039) and the presence of hepatomegaly (p=0.005).

Conclusions:

WT1 and FOXP3 overexpression has an adverse impact on clinical presentation, treatment response and survival of pediatric and adult Egyptian AML patients.

Relapsed or Refractory Lymphoblastic Lymphoma in Children: Results and Analysis of 23 Patients in the EORTC 58951 and the LMT96 Protocols

BACKGROUND

The treatment of children with T-cell lymphoblastic lymphoma (T-LBL) and precursor B-cell lymphoblastic lymphoma (pB-LBL) has improved during the last decades. However, patients with relapsed or refractory lymphomas still have a poor prognosis.

METHODS

We report the characteristics and evolution of T-LBL and pB-LBL relapses in two multicenter prospective studies (LMT 96, European Organization for Research and Treatment of Cancer 58951).

RESULTS

From 1997 to 2008, 194 patients were included in these studies (157 T-LBL; 37 pB-LBL); among them, 23 patients underwent relapse or progression (18 T-LBL and 5 pB-LBL). The median age was 7.7 years (range 1.4-16.3). The survival rate at 8 years was 8.7% (21 deaths). The median time from diagnosis to relapse was 9 months [1-69] and 11 months [1-45] for T-LBL and pB-LBL, respectively. Twenty-two patients received a second-line treatment but remission was achieved in only seven patients. In 10 patients, intensification with hematopoietic stem cell transplantation (HSCT) was performed and four of them had a second relapse. Two patients still alive had T-LBL, experienced relapses 15 and 69 months after diagnosis, and received HSCT. Relapse during the intensive phase and second-line treatment without HSCT were identified as risk factors for bad prognosis (P = 0.01).

CONCLUSIONS

The results of second-line treatment, including intensive chemotherapy and HSCT, show that salvage treatment is still disappointing in controlling refractory forms. Early identification of patients at high risk of relapse is mandatory, allowing earlier intensification. Valid prognostic parameters, such as biological markers, are needed. International cooperation is warranted to collect more data on these rare diagnoses.

Residential Proximity to Heavy-Traffic Roads, Benzene Exposure, and Childhood Leukemia-The GEOCAP Study, 2002-2007

Childhood leukemia may be associated with traffic-related environmental exposure to benzene, and additional data are needed. The Géolocalisation des Cancers Pédiatriques (GEOCAP) Study, a nationwide French case-control study, was designed to avoid selection bias due to differential participation and misclassification. The study compared the 2,760 childhood leukemia cases diagnosed in France between 2002 and 2007 (including 2,275 cases of acute lymphoblastic leukemia (ALL) and 418 cases of acute myeloblastic leukemia (AML)) with 30,000 contemporaneous child population controls. The residence addresses were precisely geocoded, and 3 indicators of residential proximity to traffic were considered. Estimates of benzene concentrations were also available for the Île-de-France region (including Paris). A 300-m increase in major road length within 150 m of the geocoded address was significantly associated with AML (odds ratio = 1.2, 95% confidence interval: 1.0, 1.4) but not with ALL (odds ratio = 1.0, 95% confidence interval: 0.9, 1.1), and the association was reinforced in the Île-de-France region when this indicator was combined with benzene estimates. These results, which were free from any participation bias and based on objectively determined indices of exposure, showed an increased incidence of AML associated with heavy-traffic road density near a child's home. The results support a role for traffic-related benzene exposure in the etiology of childhood AML.

ARID5B, IKZF1 and non-genetic factors in the etiology of childhood acute lymphoblastic leukemia: the ESCALE study

Genome-wide association studies (GWAS) have identified that frequent polymorphisms in ARID5B and IKZF1, two genes involved in lymphoid differentiation, increase the risk of childhood acute lymphoblastic leukemia (ALL). These findings markedly modified the current field of research on the etiology of ALL. In this new context, the present exploratory study investigated the possible interactions between these at-risk alleles and the non-genetic suspected ALL risk factors that were of sufficient prevalence in the French ESCALE study: maternal use of home insecticides during pregnancy, preconception paternal smoking, and some proxies for early immune modulation, i.e. breastfeeding, history of common infections before age one year, and birth order. The analyses were based on 434 ALL cases and 442 controls of European origin, drawn from the nationwide population-based case-control study ESCALE. Information on non-genetic factors was obtained by standardized telephone interview. Interactions between rs10740055 in ARID5B or rs4132601 in IKZF1 and each of the suspected non-genetic factors were tested, with the SNPs coded as counts of minor alleles (trend variable). Statistical interactions were observed between rs4132601 and maternal insecticide use (p = 0.012), breastfeeding p = 0.017) and repeated early common infections (p = 0.0070), with allelic odds ratios (OR) which were only increased among the children not exposed to insecticides (OR = 1.8, 95%CI: 1.3, 2.4), those who had been breastfed (OR = 1.8, 95%CI: 1.3, 2.5) and those who had had repeated early common infections (OR = 2.4, 95%CI: 1.5, 3.8). The allelic ORs were close to one among children exposed to insecticides, who had not been breastfed and who had had no or few common infections. Repeated early common infections interacted with rs10740055 (p = 0.018) in the case-only design. Further studies are needed to evaluate whether these observations of a modification of the effect of the at-risk alleles by non-genetic factors are chance findings or reflect true underlying mechanisms.

Head and neck presentations of B-NHL and B-AL in children/adolescents: experience of the LMB89 study

PURPOSE

Describe the epidemiology, clinical profiles and outcomes associated with head and neck (H&N) involvement in children/adolescents with B-cell non-Hodgkin lymphoma (B-NHL).

METHODS

Analysis of children/adolescents with H&N B-NHL prospectively enrolled in the SFOP LMB-89 trial (July 1989-June 1996).

RESULTS

One hundred and twelve of 561 patients (20%) had H&N involvement. The mean age of the patients was 8.4 years. Murphy staging differed between the H&N patients and the others (P < 0.0001): 9% versus 5% of the patients presented with stage I disease, 36% versus 11% presented with stage II disease, 12% versus 59% presented with stage III disease, 17% versus 10% with stage IV disease and 27% versus 16% with B-AL. Twenty-nine H&N patients (26%) had CNS involvement at diagnosis versus 8.5% in the group without H&N involvement (P < 0.0001). Patients were treated according to the LMB89 protocol: 3 H&N patients were allocated to group A, 70 to group B and 39 to group C. Ninety-seven percent of H&N patients achieved CR and event-free and overall survival at 4 years was 95.5% (5 deaths in patients with CNS disease). On multivariate analysis, EFS was significantly better in H&N patients than in non-H&N patients (P = 0.021), but not OS (P = 0.11).

CONCLUSION

The H&N site is the second most common location for B-NHL at diagnosis and is more frequently associated with disseminated disease and CNS involvement than other sites. However, outcomes are no worse for these patients than for the rest of the population.

Maternal coffee consumption during pregnancy and risk of childhood acute leukemia: a metaanalysis

OBJECTIVE

This study was undertaken to explore the association between maternal coffee consumption during pregnancy and childhood acute leukemia (AL).

STUDY DESIGN

The PubMed database was used to search studies up to May 5, 2013, and the lists of references of retrieved articles were also screened to identify additional relevant studies. Studies were included if they reported the odds ratio and corresponding 95% confidence interval (CI) of childhood AL, including childhood acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML), with respect to maternal coffee consumption during pregnancy.

RESULTS

Compared with non/lowest drinkers, the combined odds ratio regarding the relationship of maternal coffee consumption during pregnancy and childhood AL was 1.22 (95% CI, 1.04-1.43) for ever drinkers, 1.16 (95% CI, 1.00-1.34) for low to moderate-level drinkers, and 1.72 (95% CI, 1.37-2.16) for high-level drinkers. When analysis was conducted by subtypes of childhood AL, maternal coffee consumption (high-level drinkers vs non/lowest drinkers) was statistically significantly associated with childhood ALL (1.65; 95% CI, 1.28-2.12) and childhood AML (1.58; 95% CI, 1.20-2.08). We observed the linear dose-response relationship of coffee consumption and childhood AL (P for nonlinearity = .68), including childhood ALL and childhood AML; with increased coffee consumption, the risk of childhood AL increased.

CONCLUSION

The findings of the metaanalysis suggest that maternal coffee consumption during pregnancy may increase the risk of childhood AL. Because of limited studies, further prospective studies are urgently needed to explore the adverse effect of coffee consumption on childhood AL.

Potential impacts of radon, terrestrial gamma and cosmic rays on childhood leukemia in France: a quantitative risk assessment

Previous epidemiological studies and quantitative risk assessments (QRA) have suggested that natural background radiation may be a cause of childhood leukemia. The present work uses a QRA approach to predict the excess risk of childhood leukemia in France related to three components of natural radiation: radon, cosmic rays and terrestrial gamma rays, using excess relative and absolute risk models proposed by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). Both models were developed from the Life Span Study (LSS) of Japanese A-bomb survivors. Previous risk assessments were extended by considering uncertainties in radiation-related leukemia risk model parameters as part of this process, within a Bayesian framework. Estimated red bone marrow doses cumulated during childhood by the average French child due to radon, terrestrial gamma and cosmic rays are 4.4, 7.5 and 4.3 mSv, respectively. The excess fractions of cases (expressed as percentages) associated with these sources of natural radiation are 20 % [95 % credible interval (CI) 0-68 %] and 4 % (95 % CI 0-11 %) under the excess relative and excess absolute risk models, respectively. The large CIs, as well as the different point estimates obtained under these two models, highlight the uncertainties in predictions of radiation-related childhood leukemia risks. These results are only valid provided that models developed from the LSS can be transferred to the population of French children and to chronic natural radiation exposures, and must be considered in view of the currently limited knowledge concerning other potential risk factors for childhood leukemia. Last, they emphasize the need for further epidemiological investigations of the effects of natural radiation on childhood leukemia to reduce uncertainties and help refine radiation protection standards.

Childhood leukaemia close to high-voltage power lines--the Geocap study, 2002-2007

Background:

High-voltage overhead power lines (HVOLs) are a source of extremely low-frequency magnetic fields (ELF-MFs), which are classified as possible risk factors for childhood acute leukaemia (AL). The study was carried out to test the hypothesis of an increased AL incidence in children living close to HVOL of 225–400 kV (VHV-HVOL) and 63–150 kV (HV-HVOL).

Methods:

The nationwide Geocap study included all the 2779 cases of childhood AL diagnosed in France over 2002–2007 and 30 000 contemporaneous population controls. The addresses at the time of inclusion were geocoded and precisely located around the whole HVOL network.

Results:

Increased odds ratios (ORs) were observed for AL occurrence and living within 50 m of a VHV-HVOL (OR=1.7 (0.9–3.6)). In contrast, there was no association with living beyond that distance from a VHV-HVOL or within 50 m of a HV-HVOL.

Conclusion:

The present study, free from any participation bias, supports the previous international findings of an increase in AL incidence close to VHV-HVOL. In order to investigate for a potential role of ELF-MF in the results, ELF-MF at the residences close to HVOL are to be estimated, using models based on the annual current loads and local characteristics of the lines.

[Hematopoietic stem cell transplantation in 2012: who? Where? How?]

Allogeneic bone marrow transplantation has dramatically changed over the years since its beginnings. The diseases treated with transplantation (malignant hemopathies, severe benign hemopathies such as congenital or acquired congenital medullary aplasia, hemoglobinopathies, as well as severe immune system deficiencies and certain overload diseases), stem cell sources (bone marrow, peripheral stem cells, placental blood), donor types (intrafamilial, nonrelated, totally or partially compatible), conditioning regimen (immunosuppressors, graft manipulation), and supportive care increasingly vary. Allogeneic stem cell transplantation and more widely cellular therapies now need to be discussed. In this paper, we propose an overview of these therapies in 2012 for pediatric patients.

Fertility treatments, congenital malformations, fetal loss, and childhood acute leukemia: the ESCALE study (SFCE)

BACKGROUND

This study investigated the relationships between childhood acute leukemia (AL) and selective maternal and birth characteristics, including congenital malformations and the use of fertility treatment, for which the literature remains scarce.

PROCEDURE

The national registry-based case-control study ESCALE was carried out in France in 2003-2004. Population controls were frequency matched with cases on age and gender. Data were obtained from structured telephone questionnaires. Odds ratios (OR) and their 95% confidence intervals were estimated using unconditional regression models adjusted for potential confounders.

RESULTS

In all, 764 cases of AL (648 lymphoblastic AL (acute lymphoblastic leukemia, ALL) and 101 myeloblastic AL) and 1,681 controls were included. The AL cases' mothers reported congenital malformations more frequently than the controls' mothers (OR = 1.5 [1.0-2.4]). ALL was significantly associated with the use of fertility treatment for the index pregnancy (OR = 1.9 [1.3-2.8]). In particular, ALL was associated with ovulation induction only (OR = 2.6 [1.6-4.3]), but not with in vitro fertilization (IVF, OR = 1.0 [0.4-2.3]) or artificial insemination (OR = 1.3 [0.5-3.9]). A positive association was also observed for the difficulty of becoming pregnant without fertility treatment (OR = 1.5 [1.0-2.1]). AL was positively associated with a history of voluntary abortion (OR = 1.4 [1.1-1.8]) but not with a history of spontaneous (OR = 0.8 [0.7-1.0]) or therapeutic (OR = 0.7 [0.5-1.1]) abortion.

CONCLUSION

The results suggest that subfertility in itself and ovulation induction may be associated with ALL, and support a positive association with congenital malformations. The links with the various types of fertility drugs and the underlying causes of infertility need to be investigated further.

Immunologic consequences of chemotherapy for acute myeloid leukemia

There are few data characterizing the immunologic consequences of chemotherapy for acute myeloid leukemia (AML) and almost nothing is known about the effects of chemotherapy in a pediatric AML cohort. We identified T-cell subsets, B-cell subsets, and used Enzyme-linked immunosorbent spot analyses to define the function of T cells and B cells in 7 pediatric patients with AML on chemotherapy. The data show that the effects of chemotherapy disproportionately target the B cell and depletion of B cells is associated with impaired responses to the inactivated influenza vaccine. Diminished T-cell numbers were also observed although the magnitude of the effect was less than what was seen for B cells. Furthermore, measures of T-cell function were largely intact. We conclude that humoral immunity is significantly affected by chemotherapy for AML.

Folic acid supplementation, MTHFR and MTRR polymorphisms, and the risk of childhood leukemia: the ESCALE study (SFCE)

PURPOSE

Fetal folate deficiency may increase the risk of subsequent childhood acute leukemia (AL), since folates are required for DNA methylation, synthesis, and repair, but the literature remains scarce. This study tested the hypothesis that maternal folic acid supplementation before or during pregnancy reduces AL risk, accounting for the SNPs rs1801133 (C677T) and rs1801131 (A1298C) in MTHFR and rs1801394 (A66G) and rs1532268 (C524T) in MTRR, assumed to modify folate metabolism.

METHODS

The nationwide registry-based case-control study, ESCALE, carried out in 2003-2004, included 764 AL cases and 1,681 controls frequency matched with the cases on age and gender. Information on folic acid supplementation was obtained by standardized telephone interview. The genotypes were obtained using high-throughput platforms and imputation for untyped polymorphisms. Odds ratios (OR) were estimated using unconditional regression models adjusted for potential confounders.

RESULTS

AL was significantly inversely associated with maternal folic acid supplementation before and during pregnancy (OR = 0.4; 95 % confidence interval: [0.3-0.6]). MTHFR and MTRR genetic polymorphisms were not associated with AL. However, AL was positively associated with homozygosity for any of the MTHFR polymorphisms and carriership of both MTRR variant alleles (OR = 1.6 [0.9-3.1]). No interaction was observed between MTHFR, MTRR, and maternal folate supplementation.

CONCLUSION

The study findings support the hypothesis that maternal folic acid supplementation may reduce the risk of childhood AL. The findings also suggest that the genotype homozygous for any of the MTHFR variants and carrying both MTRR variants could be a risk factor for AL.

Childhood Hodgkin's lymphoma, non-Hodgkin's lymphoma and factors related to the immune system: the Escale Study (SFCE)

The study investigated the role of factors considered related to the early stimulation of the immune system in the aetiology of childhood lymphoma. The national registry-based case-control study, Escale, was carried out in France over the period 2003-2004. Population controls were frequency matched with the cases on age and gender. Data were obtained from structured telephone questionnaires administered to mothers. Odds ratios (ORs) were estimated using unconditional regression models adjusted for potential confounders. Data from 128 cases of Hodgkin's lymphoma (HL) aged 5-14 years, 164 cases of non-Hodgkin's lymphoma (NHL) aged 2-14 years and 1,312 controls were analyzed. Negative associations were observed between HL and day care attendance [OR = 0.5 (0.2-1.2)] and between HL and repeated early common infections among non-breastfed children [OR = 0.3 (.2-0.7), p = 0.003] [OR for breastfed children: 1.0 (.5-2.1)], but not for the other factors investigated. Negative associations were observed between NHL and birth order 3 or more [OR = 0.7 (0.4-1.1)], prolonged breastfeeding [OR = 0.5 (0.3-1.0)], regular contact with farm animals [OR = 0.5 (0.3-1.0)], frequent farm visits in early life [OR = 0.6 (0.4-1.1)] and history of asthma [OR = 0.6 (0.3-1.1)]. In conclusion, the results partly support the hypothesis that an abnormal maturation of the immune system may play a role in childhood HL or NHL, and call for further investigations.

Road traffic and childhood leukemia: the ESCALE study (SFCE)

BACKGROUND

Traffic is a source of environmental exposures, including benzene, which may be related to childhood leukemia.

OBJECTIVES

A national registry-based case-control study [ESCALE (Etude Sur les Cancers et les Leucémies de l'Enfant, Study on Environmental and Genetic Risk Factors of Childhood Cancers and Leukemia)] carried out in France was used to assess the effect of exposure to road traffic exhaust fumes on the risk of childhood leukemia.

METHODS

Over the study period, 2003-2004, 763 cases and 1,681 controls < 15 years old were included, and the controls were frequency matched with the cases on age and sex. The ESCALE data were collected by a standardized telephone interview of the mothers. Various indicators of exposure to traffic and pollution were determined using the geocoded addresses at the time of diagnosis for the cases and of interview for the controls. Indicators of the distance from, and density of, main roads and traffic nitrogen dioxide (NO(2)) concentrations derived from traffic emission data were used. Odds ratios (ORs) were estimated using unconditional regression models adjusted for potential confounders.

RESULTS

Acute leukemia (AL) was significantly associated with estimates of traffic NO(2) concentration at the place of residence > 27.7 µg/m(3) compared with NO(2) concentration < 21.9 µg/m(3) [OR=1.2; confidence interval (CI), 1.0-1.5] and with the presence of a heavy-traffic road within 500 m compared with the absence of a heavy-traffic road in the same area (OR=2.0; 95% CI, 1.0-3.6). There was a significant association between AL and a high density of heavy-traffic roads within 500 m compared with the reference category with no heavy-traffic road within 500 m (OR=2.2; 95% CI, 1.1-4.2), with a significant positive linear trend of the association of AL with the total length of heavy-traffic road within 500 m.

CONCLUSION

This study supports the hypothesis that living close to heavy-traffic roads may increase the risk of childhood leukemia.

Population-based incidence of childhood leukaemias and lymphomas in Spain (1993-2002)

The aim of this study was to estimate the incidence of leukaemias and lymphomas in children according to the International Classification of Childhood Cancer third edition (ICCC-3) in the population covered by the Girona, Valencia, and Zaragoza population-based cancer registries and compare it with the incidence rates in other European countries. All haematological malignancies (HMs) registered between 1993 and 2002 in children below 15 years of age were included in the study. Pathological and haematological diagnoses were reviewed, recoded according to International Classification of Diseases for Oncology-3 and reclassified on the basis of ICCC-3. Sex and age-adjusted incidence rates were calculated, using the world population as standard. Five hundred and seventy-one HMs were registered in the Girona, Valencia and Zaragoza Cancer Registries during the study period. According to ICCC-3, precursor cell leukaemias were the most frequent HMs in children and constituted 60% of all HMs (an age-adjusted incidence rate of 42.7 per million children-years). The second most frequent childhood HM was Hodgkin lymphoma (11.2% of all HMs), yielding an age-adjusted standardized incidence rate of 6.3 per million children-years. With regard to myeloid lineage, acute myeloid leukaemias were the most frequent with a rate of 7.9 per million children-years. The standardized incidence rates for lymphoid leukaemia (1.19) and Burkitt lymphoma (3.94) were statistically higher than the rates observed in Europe. Compared with European data, Spain has a high incidence of lymphoid leukaemias and lymphomas. In particular, a high incidence of Burkitt lymphoma was observed. The causes of this geographical variation are still unknown.

Childhood leukemia incidence in Brazil according to different geographical regions

BACKGROUND

Resource-rich countries tend to have a higher incidence of childhood acute lymphoblastic leukemia (ALL), whereas lower rates are seen in more deprived countries. This study describes the incidence of childhood acute leukemia in Brazil, an upper middle-income country, based on data from 16 population-based cancer registries (PBCRs).

PROCEDURE

Data were examined from 16 PBCRs in Brazilian cities located in five geographical regions during the period from 1997 to 2004. Incidence rates were analyzed according to gender, age, and type of leukemia. The Wilcoxon test was performed to evaluate for gender-age based difference between by leukemia type.

RESULTS

The median age-adjusted incidence rate (AAIR) of leukemia in children aged 0-14 years old was 53.3 per million. A different AAIR was found regarding ALL and myeloproliferative disorders (MPD) that ranged from 24.8 to 76.84 per 1,000,000 children. Manaus, although located in a poor area of Brazil, exhibited the highest AAIR (56.6 per million) of ALL. Goiania had the highest AAIR (24.5 per million) of MPD. The median age-specific incidence rate (ASIR) for the 16 Brazilian PBCRs demonstrated a marked peak in incidence of ALL at age 3 years old, in both genders.

CONCLUSIONS

This population-based study of childhood leukemia demonstrates that substantial regional differences exist regarding the incidence of acute leukemia in Brazil, which warrants further ecological study.

Childhood acute leukemia, early common infections, and allergy: The ESCALE Study

This study investigated the role of factors considered related to early stimulation of the immune system in the etiology of childhood acute leukemia. The national registry-based case-control study ESCALE was carried out in France in 2003-2004. Population controls were frequency matched to cases on age and gender. Data were obtained from structured telephone questionnaires administered to mothers. Odds ratios were estimated using unconditional regression models adjusted for potential confounders. Included were 634 acute lymphoblastic leukemia cases, 86 acute myeloblastic leukemia cases, and 1,494 controls aged ≥1 year. Negative associations were observed between acute lymphoblastic leukemia and birth order (P for trend < 0.0001), attendance at a day-care center before age 1 year (odds ratio (OR) = 0.8, 95% confidence interval (CI): 0.6, 1.1), prolonged breastfeeding (OR = 0.7, 95% CI: 0.5, 1.0), repeated early common infections (OR = 0.7, 95% CI: 0.6, 0.9), regular contact with farm animals (OR = 0.6, 95% CI: 0.5, 0.8), frequent farm visits in early life (OR = 0.4, 95% CI: 0.3, 0.6), and history of asthma (OR = 0.7, 95% CI: 0.4, 1.0) or eczema (OR = 0.7, 95% CI: 0.6, 0.9). Results support the hypothesis that repeated early infections and asthma may play a role against childhood acute leukemia.

Methotrexate pharmacokinetics in childhood acute lymphoblastic leukaemia: a prognostic value?

WHAT IS KNOWN AND OBJECTIVE

In industrialized countries, acute lymphoblastic leukaemia (ALL) is the most frequent cancer in children aged less than 15 years. High-dose methotrexate is a common component of many chemotherapeutic protocols for childhood with ALL. Our objective was to retrospectively evaluate the pharmacokinetics and plasma levels of high-dose methotrexate as it relates to event-free survival (EFS) in children with ALL.

METHODS

Relapsed patients and subjects in EFS were compared for MTX serum concentrations 24, 36, 48 and 72 h after the start of 24 h infusion. Clearance (Cl), area under the curve (AUC) and volume of distribution (V(d) ) of the drug were estimated by the NONMEM computer program and also compared between both groups.

RESULTS AND DISCUSSION

Among 69 children included, 54 (78·3%) were still in EFS, whereas 15 (21·7%) relapsed. The difference between relapsed and EFS patients for the pharmacokinetic parameters studied was not significant. On the contrary, the cohort studied was representative and known prognostic factors for relapse in ALL were significantly associated with relapse.

WHAT IS NEW AND CONCLUSION

Serum concentrations and pharmacokinetic parameters of MTX are not associated with outcome in ALL. Prognoses based on single-drug pharmacokinetic estimates within a complex multiple-agent protocol appear to be unreliable. However, therapeutic drug monitoring of high-dose methotrexate remains a useful tool for early detection of impaired elimination and for avoiding systemic toxicity.

[Is there a risk of steroid-induced adrenal deficit after induction treatment of acute lymphoblastic leukemia?]

The occurrence of eight cases of adrenal deficit in children hospitalized for acute lymphoblastic leukemia (ALL) led us to conduct a prospective study from May 2006 to May 2007 to better characterize this corticoid-induced adrenal deficit. Forty of the 48 patients hospitalized for ALL were given a low-dose Synacthen test (1 μg), a mean 7 days after the induction phase. An adrenal deficit was diagnosed in 27 patients (67.5%). No significant clinical or hematological difference was identified between the "with deficit" (n = 27) and "without deficit" (n = 13) groups. The diagnosis of adrenal deficit was not more common for children who had received dexamethasone (13/19) or prednisone (14/21), or for those who had (19/29) or had not (8/11) experienced corticoid toxicity during induction. The clinical signs suggesting adrenal deficit were identical in the two groups and none of the children presented an acute episode. In biological terms, only hypoprotidemia was significantly more common in patients with adrenal deficit (p = 0.0004). Of 13 patients with a deficit at the end of the induction who had received a 2nd low-dose Synacthène(®) test before intensification no. 1, 3 weeks on average after the end of corticotherapy, only two still had a deficit. Thus, corticoid-induced adrenal deficit is a common complication in children treated for ALL, although it is not highly symptomatic. Most of these children recover normal adrenal function before intensification no. 1, but it does not eliminate the risk of a secondary deficit after other courses of corticotherapy. Systematic repeated Synacthène(®) tests in common practice among children treated for ALL does not seem justified. However, the results of this study encouraged us to propose a hydrocortisone substitution to children treated for ALL in the event of stress.

Myeloid leukaemia in children with Down syndrome: report of the registry-based French experience between 1990 and 2003

AIM

To determine the epidemiology of myeloid leukaemia (ML) in children with Down syndrome (DS) and the efficacy of two approaches, low-dose cytarabine-based regimen (LDC) and standard-dose intensive chemotherapy (SD).

PROCEDURE

All children with Down syndrome aged from 2 months to 15 years with ML/myelodysplasia registered in the French registry between January 1990 and December 2003 were included.

RESULTS

Forty-four patients were included. The median age was 1.75 years. The French-America-British subtypes were as follows: M7: 24, M0: 6, M2: 5, M6: 2. Forty-three patients were treated with curative prospect, 20 patients with LDC regimen and 22 according to SD protocols, 1 was given the LDC regimen plus autologous stem-cell transplantation. The event-free survival (EFS) and overall survival (OS) at 5 years were 64.4% and 76.8%. At 5 years, OS in LDC and SD groups were 65% and 85.9% (P = 0.08). EFS were 45% and 80.3% respectively (P < 0.01).

CONCLUSION

Children with DS can adequately tolerate SD chemotherapy with a significant superiority of EFS relative to LDC. We suggest that higher levels of cure can be obtained in DS-ML with SD chemotherapy including cytarabine and anthracyclines.

Acute myeloid leukemia

Acute myeloid leukemia (AML) is a heterogeneous group of leukemias that result from clonal transformation of hematopoietic precursors through the acquisition of chromosomal rearrangements and multiple gene mutations. As a result of highly collaborative clinical research by pediatric cooperative cancer groups worldwide, disease-free survival has improved significantly during the past 3 decades. Further improvements in outcomes of children who have AML probably will reflect continued progress in understanding the biology of AML and the concomitant development of new molecularly targeted agents for use in combination with conventional chemotherapy drugs.

Childhood hematopoietic malignancies and parental use of tobacco and alcohol: the ESCALE study (SFCE)

OBJECTIVES

Investigating the role of parental smoking and maternal alcohol consumption in the etiology of childhood hematopoietic malignancies.

METHODS

The national registry-based case-control study ESCALE was carried out in France over the period 2003-2004. Population controls were frequency matched with the cases on age and gender. Maternal smoking and alcohol consumption during pregnancy and paternal smoking since before conception were reported by the mothers in a structured telephone questionnaire. Odds ratios (OR) were estimated using unconditional regression models closely adjusted for potential confounders.

RESULTS

A total of 765 cases of acute leukemia (AL), 130 of Hodgkin's lymphoma (HL), 165 of non-Hodgkin's lymphoma (NHL) and 1681 controls were included. Paternal smoking was significantly associated with childhood ALL (OR = 1.4 [1.1-1.7]), AML (OR = 1.5 [1.0-2.3]), Burkitt (OR = 2.0 [1.2-3.2]), and anaplastic large cell (OR = 3.2 [1.2-9.1]) NHL. For the four diseases, the ORs significantly increased with the number of cigarettes smoked. No association with HL or with other types of NHL was observed. The associations with maternal alcohol consumption and cigarette smoking during pregnancy were less consistent.

CONCLUSION

The results support the hypothesis that only paternal smoking, and not maternal alcohol consumption or cigarette smoking, plays a role in childhood hematopoietic malignancies.

Parental smoking, maternal alcohol, coffee and tea consumption during pregnancy and childhood malignant central nervous system tumours: the ESCALE study (SFCE)

Parental smoking and maternal alcohol and caffeinated beverage consumption are prevalent exposures which may play a role, either directly or through their influence on metabolism, in the aetiology of childhood malignant central nervous system (CNS) tumours. The hypothesis was investigated in the Epidemiological Study on childhood Cancer and Leukemia ESCALE study, a national population-based case-control study carried out in France in 2003-2004. The study included 209 incident cases of CNS tumours and 1681 population-based controls, frequency matched with the cases by age and sex. The data were collected through a standardized telephone interview of the biological mothers. No association between maternal smoking during pregnancy and CNS tumours [odds ratio (OR): 1.1 (0.8-1.6)] was observed. Paternal smoking during the year before birth was associated with CNS tumours (P for trend=0.04), particularly astrocytomas [OR: 3.1 (1.3-7.6)]. Maternal alcohol consumption during pregnancy was not associated with CNS tumours. Associations between ependymomas and the highest consumption of coffee [OR: 2.7 (0.9-8.1)] and tea [OR: 2.5 (1.1-5.9)] were observed. A strong association between CNS tumours and the highest maternal consumption of both coffee and tea during pregnancy was observed [OR: 4.4 (1.5-13)]. The results constitute additional evidence for a role of paternal smoking and suggest that maternal coffee and tea consumption during pregnancy may also increase the risk of CNS tumours. The study does not suggest an increased risk of CNS tumours related to alcohol consumption during pregnancy.

Descriptive epidemiology of childhood Langerhans cell histiocytosis in France, 2000-2004

INTRODUCTION

Childhood Langerhans cell histiocytosis (LCH) is a rare and poorly understood multisystemic disease. The French National Registry of Childhood Hematopoietic Malignancies (NRCH) has recorded LCH cases of all subtypes since 2000. The present study describes the data on LCH collected on a national scale over a 5-year period.

MATERIALS AND METHODS

The cases were children aged less than 15 years, diagnosed with LCH of any type between 2000 and 2004, and residing in mainland France at the time of diagnosis. Completeness was evaluated by capture-recapture after cross-checking against the database compiled by the French Langerhans Cell Histiocytosis Study Group.

RESULTS

Two hundred fifty-eight cases of LCH were registered. The completeness of the NRCH was estimated to be 97%. The annual incidence rate was 4.6/10(6) children aged less than 15 years and the sex ratio was 1.2. Bone and skin were the most commonly involved organs at diagnosis. The incidence rate decreased with age from 15.3/10(6) before 1 year to 2.0/10(6) after 10 years. The disease was mainly unifocal (2.6/10(6)) and rarely disseminated (0.6/10(6)), but disseminated forms predominated in infants. The overall 2-year survival rate was 99% (95%CI: [97; 100]). About 30% of the LCH cases were enrolled in a clinical trial at first onset. No case was treated by radiotherapy.

CONCLUSION

This study evidenced the main features of LCH incidence in the overall population and was consistent with previous studies. The NRCH thus appears to be a very promising tool for further elucidation of LCH.

Birth-related characteristics, congenital malformation, maternal reproductive history and neuroblastoma: the ESCALE study (SFCE)

Since neuroblastoma occurs very early in children's lives, it has been hypothesized that pre- and perinatal factors may play a role in its etiology. This study investigated the role of birth characteristics, congenital malformation and maternal reproductive history in neuroblastoma. The data used were generated by the national population-based case-control study, ESCALE, conducted in France in 2003-2004. The mothers of 191 neuroblastoma cases and 1,681 controls, frequency-matched by age and gender, were interviewed by telephone, using a standardized questionnaire, on several factors including pregnancy, medical history, lifestyle, childhood medical conditions and exposures. A positive association between congenital malformation and all neuroblastoma cases was observed [Odds ratio (OR) = 2.2, 95% confidence interval (95% CI): 1.1-4.5]. Congenital malformations were highly associated to neuroblastoma in children aged less than 1 year (OR = 16.8, 95% CI: 3.1-90), while no association was observed in children aged 1 year or more (OR = 1.0, 95% CI: 0.3-2.9). A negative association with a maternal history of spontaneous abortions was also found (OR = 0.6, 95% CI: 0.4-0.9). The results strongly support the hypothesis that congenital anomalies may be associated with neuroblastoma, particularly in infant (less than 1 year of age).

Hematological malignancies diagnosed by bone marrow examination in a tertiary hospital at Uttarakhand, India

INTRODUCTION

Hematological malignancies are quite common and affect all ages and genders. The diagnosis involves a multiparameter approach. The geographical distribution of various types of hematological malignancies has been provided by various authors but no such data have been published regarding the State of Uttarakhand in India.

AIM

To study the hematological malignancies at Uttarakhand in India based on age, sex and the type of malignancy with further sub typing wherever possible.

SETTINGS AND DESIGN

A total of 220 cases of hematological malignancies were worked up from the Reference Laboratory of Himalayan Institute of Medical Sciences over an eight year period (1998-2005).

MATERIALS AND METHODS

Diagnosis was mainly based on morphological examination of peripheral blood and bone marrow smears stained by Leishman's stain and MPO, Sudan Black and PAS stain as and where required. Distribution of cases was studied based on age, sex and the type of malignancy with further sub typing wherever possible.

RESULTS

The most common hematological malignancy was found to be Leukemia 129/220 (58%) followed b Lymphoma 33/220 (14.8%), Multiple Myeloma 55/220 (24.7%) and Metastatic Lesions 3/220 (1.3%). These malignancies were seen to be distributed throughout all ages with a peak at 11-20 years age group 39/220 (17.5%) and another peak at 51-60 years age group 41/220 (18.4%). We found an overall male preponderance with a M:F ratio of 2.3:1.

CONCLUSIONS

The commonest haematological malignancy in our series was Leukemia. Other diagnoses were Multiple Myeloma, Lymphoma and Secondaries. Multiple Myeloma which turned out to be the second most common diagnosis was an unusual finding.

Acute myeloid leukemia

Acute myeloid leukemia (AML) is a heterogeneous group of leukemias that result from clonal transformation of hematopoietic precursors through the acquisition of chromosomal rearrangements and multiple gene mutations. As a result of highly collaborative clinical research by pediatric cooperative cancer groups worldwide, disease-free survival has improved significantly during the past 3 decades. Further improvements in outcomes of children who have AML probably will reflect continued progress in understanding the biology of AML and the concomitant development of new molecularly targeted agents for use in combination with conventional chemotherapy drugs.

Trends in childhood acute lymphoblastic leukemia in Western Australia, 1960-2006

Increases in the incidence of childhood acute lymphoblastic leukemia (ALL) have been reported in some countries, while other reports from similar geographical regions have indicated stable rates. The reasons for the discrepancies have been debated in the literature, with the focus on whether the observed increases are "real" or an artifact resulting from improvements in diagnosis, case ascertainment and population coverage over time. We used population-based data from Western Australia to investigate trends in the incidence of childhood ALL between 1960 and 2006. Age-standardized incidence rates (ASRs) and rate ratios (indicating annual percent change) were estimated using Poisson regression. Between 1960 and 2006, the ASR was 3.7 per 100,000 person-years, with an annual percent increase of 0.40% (95% CI: -0.20, 1.00). Between 1982 and 2006, the ASR was 3.8, with an annual percent increase of 0.80% (95% CI = -0.70 to 2.30). This increased to 1.42% (95% CI: -0.30, 3.0) when a sensitivity analysis was undertaken to assess the effect of excluding the final 2 years of data. Annual increases of 3.7% (95% CI: -0.50, 8.00) among children aged 5-14 years, and of 3.10% (95% CI: 0.50, 5.70) in girls, were observed for this latter period. These results were supported by national Australian incidence data available for 1982-2003. There may have been a small increase in the incidence of ALL since 1982 among girls and older children, but an overall increase appears unlikely. No impact of folate supplementation or fortification is apparent.

Epidemiological studies of leukaemia in children and young adults around nuclear facilities: a critical review

The existence of an increased risk of childhood leukaemia near nuclear installations is a recurrent issue. A review of the related epidemiological literature is presented here. Results for 198 nuclear sites throughout 10 countries were included in the review. In addition to local studies, 25 multi-site studies have been published for eight countries. A large variability was noticed in the quality of the data as well as in the definition of the study population and in the methods of analysis. Many studies present important limits that make the results difficult to interpret. The review confirms that some clusters of childhood leukaemia cases exist locally. However, results based on multi-site studies around nuclear installations do not indicate an increased risk globally. Many studies were launched to investigate possible origins of the observed clusters around specific sites, but up to now, none of the proposed hypotheses have explained them.

Incidence of childhood cancer in Switzerland: the Swiss Childhood Cancer Registry

BACKGROUND

This report describes the incidence of childhood cancer in Switzerland, based on the data from the Swiss Childhood Cancer Registry (SCCR), a national hospital-based cancer registry with very high coverage, founded in 1976 by the Swiss Paediatric Oncology Group (SPOG).

PROCEDURE

Malignancies were coded according to the International Classification of Childhood Cancer (ICCC-3). Incidence rates per 100,000 person-years were calculated for all malignancies and groups of malignancies in Swiss residents less than 15 years of age for the decade 1995-2004.

RESULTS

The SCCR annually registered on average 174 new cases of cancer in Swiss residents aged <15 years, with a median age at diagnosis of 5.6 years. The crude incidence of childhood cancer in children aged <15 years was 13.5, higher for boys (15.0 per 100,000) than for girls (12.1 per 100,000), and was nearly twice as high in the first 5 years of life (19.3 per 100,000) than in the age group 5 to 14 years (10.8 per 100,000).

CONCLUSION

Incidence of childhood cancers in the SCCR was similar to neighbouring countries and to data published by regional cancer registries in Switzerland for the same period, suggesting good completeness of registration. This makes the SCCR a valuable resource for national and international research on childhood cancer.

Childhood leukaemia and population movements in France, 1990-2003

In a national study, we investigated the incidence of childhood leukaemia (CL) over a 14-year period in France in relation to several measures based on the proportion of individuals who changed address between the last two national censuses. A positive association was found with the proportion of migrants who came from a distant place. The further the migrants came, the higher was the incidence of leukaemia, particularly among children aged 0-4 years in 'isolated' communes at the time of diagnosis (RR=1.4, 95% CI: 1.1,1.8 in the highest category of migration distance). Although the role of the population density was less obvious, a more marked association was found above a certain threshold. No association with the proportion of commuters was observed.

Household exposure to pesticides and risk of childhood hematopoietic malignancies: The ESCALE study (SFCE)

OBJECTIVES

We investigated the role of household exposure to pesticides in the etiology of childhood hematopoietic malignancies.

METHODS

The national registry-based case-control study ESCALE (Etude sur les cancers de l'enfant) was carried out in France over the period 2003-2004. Population controls were frequency matched with the cases on age and sex. Maternal household use of pesticides during pregnancy and paternal use during pregnancy or childhood were reported by the mothers in a structured telephone questionnaire. Insecticides (used at home, on pets, or for garden crops), herbicides, and fungicides were distinguished. We estimated odds ratios (ORs) using unconditional regression models closely adjusting for age, sex, degree of urbanization, and type of housing (flat or house).

RESULTS

We included a total of 764 cases of acute leukemia (AL), 130 of Hodgkin lymphoma (HL), 166 of non-Hodgkin lymphoma (NHL), and 1,681 controls. Insecticide use during pregnancy was significantly associated with childhood AL [OR = 2.1; 95% confidence interval (CI), 1.7-2.5], both lymphoblastic and myeloblastic, NHL (OR = 1.8; 95% CI, 1.3-2.6), mainly for Burkitt lymphoma (OR = 2.7; 95% CI, 1.6-4.5), and mixed-cell HL (OR = 4.1; 95% CI, 1.4-11.8), but not nodular sclerosis HL (OR = 1.1; 95% CI, 0.6-1.9). Paternal household use of pesticides was also related to AL (OR = 1.5; 95% CI, 1.2-1.8) and NHL (OR = 1.7; 95% CI, 1.2-2.6); but for AL the relationships did not remain after adjustment for maternal pesticide use during pregnancy.

CONCLUSION

The study findings strengthen the hypothesis that domestic use of pesticides may play a role in the etiology of childhood hematopoietic malignancies. The consistency of the findings with those of previous studies on AL raises the question of the advisability of preventing pesticide use by pregnant women.

Familial history of cancer and childhood acute leukemia: a French population-based case-control study

A case-control study was conducted to investigate the role of a familial history of cancer in the etiology of childhood acute leukemia. The history of cancer in the relatives of 472 cases was compared with that of 567 population-based controls. Recruitment was frequency matched on age, sex and region. The familial history of cancer in each child's relatives was reported by the mother in response to a standardized self-administered questionnaire. A familial history of solid tumor in first or second-degree relatives was associated with an increased risk of acute lymphoblastic leukemia (odds ratio (OR)=1.6 [95% confidence interval, 1.2-2.1]), while a familial history of hematopoietic malignancies in first or second-degree relatives was associated with an increased risk of acute myeloid leukemia (OR=4.3 [1.4-13]). The ORs for the histories of cancer increased with the number of relatives with cancer (OR=1.5 [1.1-2.0] for one relative and OR=2.3 [1.3-3.8] for two relatives or more; Ptrend<0.0001). Significant associations between childhood acute leukemia and familial history of genital cancers and brain tumor were also observed (OR=2.7 [1.2-5.8] and OR=10.7 [1.3-86], respectively). This study supports the hypothesis that a familial history of cancer may play a role in the etiology of childhood acute leukemia. It also evidences some specific associations that require further investigation.

Robustness of the BYM model in absence of spatial variation in the residuals

Background

In the context of ecological studies, the Bayesian hierarchical Poisson model is of prime interest when studying the association between environmental exposure and rare diseases. However, adding spatially structured extra-variability in the model fitted to the data when such extra-variability does not exist conditionally on the covariates included in the model (over-fitting) may bias the estimation of the ecological association between covariates and relative risks toward the null. In order to investigate that possibility, a simulation study of the impact of introducing unnecessary residual spatial structure in the estimation model was conducted.

Results

In the case where no underlying extra-variability from the Poisson process exists, the simulation results show that models accounting for structured and unstructured residuals do not underestimate the ecological association, unless covariates have a very strong autocorrelation structure, i.e., 0.98 at 100 km on a territory of diameter 1000 km."