Cancer surveillance series: recent trends in childhood cancer incidence and mortality in the United States

Epidemiologic evidence of relationships between reproductive and child health outcomes and environmental chemical contaminants

This review summarizes the level of epidemiologic evidence for relationships between prenatal and/or early life exposure to environmental chemical contaminants and fetal, child, and adult health. Discussion focuses on fetal loss, intrauterine growth restriction, preterm birth, birth defects, respiratory and other childhood diseases, neuropsychological deficits, premature or delayed sexual maturation, and certain adult cancers linked to fetal or childhood exposures. Environmental exposures considered here include chemical toxicants in air, water, soil/house dust and foods (including human breast milk), and consumer products. Reports reviewed here included original epidemiologic studies (with at least basic descriptions of methods and results), literature reviews, expert group reports, meta-analyses, and pooled analyses. Levels of evidence for causal relationships were categorized as sufficient, limited, or inadequate according to predefined criteria. There was sufficient epidemiological evidence for causal relationships between several adverse pregnancy or child health outcomes and prenatal or childhood exposure to environmental chemical contaminants. These included prenatal high-level methylmercury (CH(3)Hg) exposure (delayed developmental milestones and cognitive, motor, auditory, and visual deficits), high-level prenatal exposure to polychlorinated biphenyls (PCBs), polychlorinated dibenzofurans (PCDFs), and related toxicants (neonatal tooth abnormalities, cognitive and motor deficits), maternal active smoking (delayed conception, preterm birth, fetal growth deficit [FGD] and sudden infant death syndrome [SIDS]) and prenatal environmental tobacco smoke (ETS) exposure (preterm birth), low-level childhood lead exposure (cognitive deficits and renal tubular damage), high-level childhood CH(3)Hg exposure (visual deficits), high-level childhood exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) (chloracne), childhood ETS exposure (SIDS, new-onset asthma, increased asthma severity, lung and middle ear infections, and adult breast and lung cancer), childhood exposure to biomass smoke (lung infections), and childhood exposure to outdoor air pollutants (increased asthma severity). Evidence for some proven relationships came from investigation of relatively small numbers of children with high-dose prenatal or early childhood exposures, e.g., CH(3)Hg poisoning episodes in Japan and Iraq. In contrast, consensus on a causal relationship between incident asthma and ETS exposure came only recently after many studies and prolonged debate. There were many relationships supported by limited epidemiologic evidence, ranging from several studies with fairly consistent findings and evidence of dose-response relationships to those where 20 or more studies provided inconsistent or otherwise less than convincing evidence of an association. The latter included childhood cancer and parental or childhood exposures to pesticides. In most cases, relationships supported by inadequate epidemiologic evidence reflect scarcity of evidence as opposed to strong evidence of no effect. This summary points to three main needs: (1) Where relationships between child health and environmental exposures are supported by sufficient evidence of causal relationships, there is a need for (a) policies and programs to minimize population exposures and (b) population-based biomonitoring to track exposure levels, i.e., through ongoing or periodic surveys with measurements of contaminant levels in blood, urine and other samples. (2) For relationships supported by limited evidence, there is a need for targeted research and policy options ranging from ongoing evaluation of evidence to proactive actions. (3) There is a great need for population-based, multidisciplinary and collaborative research on the many relationships supported by inadequate evidence, as these represent major knowledge gaps. Expert groups faced with evaluating epidemiologic evidence of potential causal relationships repeatedly encounter problems in summarizing the available data. A major driver for undertaking such summaries is the need to compensate for the limited sample sizes of individual epidemiologic studies. Sample size limitations are major obstacles to exploration of prenatal, paternal, and childhood exposures during specific time windows, exposure intensity, exposure-exposure or exposure-gene interactions, and relatively rare health outcomes such as childhood cancer. Such research needs call for investments in research infrastructure, including human resources and methods development (standardized protocols, biomarker research, validated exposure metrics, reference analytic laboratories). These are needed to generate research findings that can be compared and subjected to pooled analyses aimed at knowledge synthesis.

Selective cancer-germline gene expression in pediatric brain tumors

Cancer-germline genes (CGGs) code for immunogenic antigens that are present in various human tumors and can be targeted by immunotherapy. Their expression has been studied in a wide range of human tumors in adults. We measured the expression of 12 CGGs in pediatric brain tumors, to identify targets for therapeutic cancer vaccines. Real Time PCR was used to quantify the expression of genes MAGE-A1, MAGE-A2, MAGE-A3, MAGE-A4, MAGE-A6, MAGE-A10, MAGE-A12, MAGE-C2, NY-ESO-1 and GAGE-1,2,8 in 50 pediatric brain tumors of different histological subtypes. Protein expression was examined with immunohistochemistry. Fifty-five percent of the medulloblastomas (n = 11), 86% of the ependymomas (n = 7), 40% of the choroid plexus tumors (n = 5) and 67% of astrocytic tumors (n = 27) expressed one or more CGGs. Immunohistochemical analysis confirmed qPCR results. With exception of a minority of tumors, the overall level of CGG expression in pediatric brain tumors was low. We observed a high expression of at least one CGG in 32% of the samples. CGG-encoded antigens are therefore suitable targets in a very selected group of pediatric patients with a brain tumor. Interestingly, glioblastomas from adult patients expressed CGGs more often and at significantly higher levels compared to pediatric glioblastomas. This observation is in line with the notion that pediatric and adult glioblastomas develop along different genetic pathways.

Reduced frontal white matter volume in long-term childhood leukemia survivors: a voxel-based morphometry study

BACKGROUND AND PURPOSE

To our knowledge, no published studies have examined whole-brain regional differences to identify more discrete volumetric changes in the brains of childhood leukemia survivors. We used voxel-based morphometry (VBM) to examine regional gray and white matter differences in a group of long-term survivors of acute lymphoblastic leukemia (ALL) compared with a group of healthy controls. Differences in regional white matter volume were expected, given previous reports of white matter changes during treatment for ALL and reduced brain white matter volumes in long-term survivors. Follow-up analyses examined the relationship of regional brain volumes to cognitive function.

MATERIALS AND METHODS

We compared 9 long-term survivors of ALL with 14 healthy controls. Survivors of ALL were treated with systemic and intrathecal chemotherapy only. T1-weighted axial 3D spoiled gradient high-resolution images collected on a 1.5T MR imaging scanner were used for the VBM analysis. Neuropsychological evaluations were conducted within 2 months of the MR imaging to assess cognitive function.

RESULTS

VBM analysis revealed 2 specific regions of reduced white matter in the right frontal lobes of survivors of ALL compared with healthy controls. Survivors of ALL had lower performances on tests of attention, visual-constructional skills, mental flexibility, and math achievement compared with healthy individuals. Decreased performance on neuropsychological measures was associated with decreased regional white matter volumes. No differences were found between the groups with respect to gray matter regions.

CONCLUSION

These findings are consistent with previous literature describing the long-term cognitive, academic, and imaging findings of survivors of ALL and suggest that right frontal white matter is particularly vulnerable to disruption following intensive chemotherapy for ALL. Future studies should focus on further clarifying the white matter changes observed.

Temporal trends in the incidence rate of childhood cancer in Germany 1987-2004

The German Childhood Cancer Registry regularly presents graphs of childhood cancer incidence rates by period, but no systematic analysis. The Automated Childhood Cancer Information System-project found an increasing trend in Europe. Against this background we present the first detailed trend analysis of childhood (aged under 15) malignancies in Germany. We examined incidence rates separately in western Germany 1987-2004 and eastern Germany 1991-2004. We analyzed all malignancies, all main diagnostic groups and relevant subsets using an age-period-cohort model. Additionally we fitted fractional polynomials to assess the linearity of the drift. All malignancies combined (excluding Central Nervous System-tumors and neuroblastoma) show a significant trend: +0.7% in western and +1.1% per year in eastern Germany. The overall trend in Germany is mostly due to the significant increase in lymphoid leukemia, which increased significantly in western Germany (+0.7% per year) and significantly nonlinearly in eastern Germany (+3.3% per year until 1998, +0.8% since 1998), catching up from a level 20% below western Germany. This could be due to life style changes since the reunification in eastern Germany influencing early immune system training. We found no trends for acute non-lymphocytic leukemia and non-Hodgkin lymphoma. Hodgkin's disease shows a cohort effect in western Germany after reunification. Improved registration of CNS tumors led to an increase. Neuroblastoma yielded a period effect in western Germany due to screening. With the exception of germ cell tumors, further observations for solid tumor entities are in agreement with those reported for Europe.

Trends in childhood cancer incidence in the U.S. (1992-2004)

BACKGROUND

The etiology of most pediatric neoplasms remains elusive. Examination of population-based incidence data provides insight regarding etiology among various demographic groups and may result in new hypotheses. The objective of the current study was to present updated information regarding childhood cancer incidence and trends in the U.S. overall and among demographic subgroups, including Asian/Pacific Islanders and Hispanics, for whom to the authors' knowledge trends have not been previously examined.

METHODS

Data obtained by 13 registries of the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) program were evaluated to assess incidence and trends of common primary cancers diagnosed between 1992 and 2004 among children aged birth to 19 years. Frequencies, age-adjusted incidence rates, and joinpoint regression results, including annual percent change (APC) in incidence rates (and 95% confidence intervals [95% CI]), were calculated.

RESULTS

Between 1992 and 2004, a modest, nonsignificant increase in the average annual incidence rate (APC, 0.4%; 95% CI, -0.1%-0.8%) was observed for all pediatric cancer diagnoses combined. There was a suggestion of an increase in leukemia (APC, 0.7%; 95% CI, -0.1%-1.5%), and acute lymphoblastic leukemia in particular (APC, 0.8%; 95% CI, -0.4%-1.9%), whereas rates for central nervous system tumors overall were stable (APC, -0.1%; 95% CI, -1.1%-1.0%); 2 joinpoints were observed for astrocytoma. Rate increases were noted for hepatoblastoma (APC, 4.3%; 95% CI, 0.2%-8.7%) and melanoma (APC, 2.8%; 95% CI, 0.5%-5.1%). Differences by demographic group (sex, age, and race/ethnicity) are also described.

CONCLUSIONS

The observed trends reinforce an ongoing need for population-based surveillance and further etiologic studies.

Attention and memory in children with brain tumors

The Rey Auditory Verbal Learning Test was utilized to examine attention, learning, and memory abilities in 42 children with cerebellar (N = 18) and third ventricle tumors (N = 24). Children with cerebellar tumors exhibited significant auditory attentional impairments and displayed adequate encoding and retrieval across subsequent learning and memory trials. In contrast, children with third ventricle tumors exhibited average auditory attentional abilities, but they displayed mild encoding deficits across trials 2-5. Furthermore, the third ventricle group's compromised performance on the delayed recall trial and average performance on the delayed recognition trial is suggestive of underlying retrieval deficits.

Early death in children with acute lymphoblastic leukemia: does malnutrition play a role?

The study aim was to correlate malnutrition and early death in children with acute lymphoblastic leukemia (ALL). A study was conducted in 100 consecutive children with ALL. An analysis included clinical and laboratory parameters as well as co-morbidity factors. Forty patients were standard risk and 60 high risk. Multivariate analysis showed variables of statistical importance, including female gender (p 010), ALL high-risk (p 04), and infection (p 036). Malnutrition (p 1.0) and poverty (p 0.5) did not influence. Early mortality was documented in 15/100 (15%) patients. The study shows that high-risk ALL and infection represent the leading causes of early mortality.

Nonrhabdomyosarcoma soft tissue sarcoma (NRSTS)

Nonrhabdmyosarcoma soft tissue sarcoma (NRSTS) is a heterogenous group of tumors analyzed as a unique group because of the rarity of each histopathological subtype. Initial information available has been obtained from adult series or pediatric case studies. Recent reports by several multi-center groups have been published that evaluated prognostic factors and treatment protocols. Established prognostic factors include tumor grade, invasiveness, size, and intergroup rhabdomyosarcoma study (IRS) group. Identification of sarcoma-specific chromosomal translocations has allowed for more accurate definitive diagnosis. Some may have prognostic significance and may offer as potential therapeutic targets. Surgery remained important, as many of the tumors are scarcely chemosensitive. With the development of multimodalities, surgical management has evolved over the years. Patients with localized unresectable disease are managed with surgery +/- radiotherapy with very good results. Localized unresectable disease is intermediate in behavior and prognosis. Patients are treated with neoadjuvant chemotherapy, +/- radiotherapy, followed by delayed surgical resection. Prognosis in patients with metastatic disease has been poor despite combination chemotherapy with surgical resection. The addition of ifosfamide and doxorubicin in the chemotherapy regimes has provided some improvement. With the lack of new active agents, we will depend on advances in molecular techniques to develop novel targeted therapies, better molecular markers and histology-specific trials to evaluate this group of tumors.

Use of complementary and alternative medicine in children with cancer in Occidental, Mexico

PURPOSE

To describe the types of complementary and alternative medicine (CAM) used by pediatric cancer patients attending a tertiary care hospital in Western Mexico.

PATIENTS AND METHODS

In a cross-sectional survey, parents were interviewed and types of CAM employed as well as factors related to their use and their perceived effectiveness were determined.

RESULTS

One hundred ten parents of pediatric cancer patients completed the survey. Seventy-seven patients (70%) received CAM. Of CAM used, herbal remedies (69%) and orally administered products (26%) were most common. Mean number of therapies was 2 +/- 1.1 (95% CI 1.59-2.12). Prior CAM use by the family was associated with use in patients (P = 0.006) (OR 4.6, CI 95% 1.7-12.9). Perceived usefulness was reported in 79% of CAM users.

CONCLUSION

CAM use in Mexican children is common, most frequently with herbal therapies. The majority perceived benefits with its usage but in most cases, the treating physician was not informed about this practice.

Trends in childhood leukemia mortality in Brazil and correlation with social inequalities

BACKGROUND

Mortality from childhood leukemia has declined substantially in developed countries but less markedly in the developing world. This study was designed to describe mortality trends in childhood leukemia and the impact of social inequalities on these trends in Brazil from 1980 to 2002.

METHODS

Cancer mortality data by cause and estimates of resident population stratified by age and sex were obtained from the Brazilian Mortality Information System (SIM) for the years 1980 to 2002. Age-standardized (ages 0-19 years) mortality rates were calculated by the direct method using the 1960 world standard population. Trends were modeled using linear regression with 3-year moving average rates as the dependent variable and with the midpoint of the calendar year interval (1991) as the independent variable. The Index of Social Exclusion was used to classify the 27 Brazilian states. Pearson correlation was used to describe the correlation between social exclusion and variations in mortality in each state.

RESULTS

Age-standardized mortality rates for boys decreased from 2.05 per 100,000 habitants in 1984 to 1.44 100,000 habitants in 1995, whereas the observed corresponding decline among girls was from 1.60 per 100,000 habitants in 1986 to 1.14 per 100,000 habitants in 1995. Statistically significant declining trends in mortality rates were observed for boys (adjusted correlation coefficient [r(2)] = 0.68; P < .001) and girls (adjusted r(2) = 0.62; P < .001). Significant negative correlations between social inequality and changes in mortality were noted for boys (r = -0.66; P = .001) and for girls (r = -0.78; P < .001).

CONCLUSIONS

A consistent decrease in mortality rates from childhood leukemia was noted in Brazil. Higher decreases in mortality were observed in more developed states, possibly reflecting better health care.

Childhood cancer in Ireland: a population-based study

BACKGROUND

Population-based studies of childhood cancer incidence, survival and mortality make an important contribution to monitoring the successful implementation of new treatment guidelines and to understanding the epidemiology of these diseases.

METHODS

We analysed incidence and survival data for cancers diagnosed in children under 15 years of age in the Republic of Ireland during 1994-2000 (the first 7 years of National Cancer Registry coverage), and longer term mortality trends.

RESULTS

World age-standardised incidence rates in Ireland averaged 142 cases per million children per year, slightly higher than the European average and slightly lower than the US average, although differences varied by diagnostic group. Observed 5-year survival in Ireland (79% overall) was slightly higher than European and US averages, and was significantly higher for acute non-lymphocytic leukaemia (67%) and (compared with the USA) significantly lower for Hodgkin lymphoma (83%). No significant increases in incidence rates were evident from the available 7 years' data, either overall or for particular diagnostic groups. Rates of childhood cancer mortality have declined markedly since the 1950s.

CONCLUSIONS

Data presented here are in line with other developed countries and suggest major improvements in treatment and consequent survival.

Presentation of childhood CNS tumours: a systematic review and meta-analysis

BACKGROUND

Suspicion of a CNS tumour is classically raised by symptoms of raised intracranial pressure, focal deficits (including seizures), or papilloedema. Development of guidelines is needed for the identification and referral of children who might have a CNS tumour. We did a systematic literature review and meta-analysis to identify the clinical presentation of childhood CNS tumours to provide evidence to support the development of guidelines to assist with the identification and referral for imaging of children who might have a central nervous system tumour.

METHODS

Medline, Embase, and PubMed were searched for cohort studies and case series in children, published between January, 1991, and August, 2005, detailing the symptoms and signs at diagnosis of a CNS tumour.

FINDINGS

74 papers (n=4171) met the inclusion criteria. 56 symptoms and signs at diagnosis were identified, ranked by frequency, and clustered according to age, anatomical criteria, and genetic criteria. The most frequent symptoms and signs at diagnosis were: headache (33%), nausea and vomiting (32%), abnormalities of gait and coordination (27%), and papilloedema (13%) for intracranial tumours; macrocephaly (41%), nausea and vomiting (30%), irritability (24%), and lethargy (21%) for children aged under 4 years with intracranial tumours; reduced visual acuity (41%), exophthalmia (16%), and optic atrophy (15%) for children with an intracranial tumour and neurofibromatosis; nausea and vomiting (75%), headache (67%), abnormal gait and coordination (60%), and papilloedema (34%) for posterior fossa tumours; unspecified symptoms and signs of raised intracranial pressure (47%), seizures (38%), and papilloedema (21%) for supratentorial tumours; headache (49%), abnormal eye movements (21%), squint (21%), and nausea and vomiting (19%) for central brain tumours; abnormal gait and coordination (78%), cranial nerve palsies (52%), pyramidal signs (33%), headache (23%), and squint (19%) for brainstem tumours; and back pain (67%), abnormalities of gait and coordination (42%), spinal deformity (39%), focal weakness (21%), and sphincter disturbance (20%) for spinal-cord tumours. Other features noted were weight loss, growth failure, and precocious puberty. Symptoms of raised intracranial pressure were absent in more than half of children with brain tumours. Other neurological features were heterogeneous and related to tumour location.

INTERPRETATION

Apart from raised intracranial pressure, motor and visual system abnormalities, weight loss, macrocephaly, growth failure, and precocious puberty also suggest presence of an intracranial tumour. Children with signs and symptoms that could result from a CNS tumour need a thorough visual and motor system examination and an assessment of growth and pubertal status. Occurrence of multiple symptoms and signs should alert clinicians to possible CNS tumours.

1 alpha-Hydroxyvitamin D2 inhibits growth of human neuroblastoma

Neuroblastoma is the most common extracranial solid tumor in childhood. The poor outcomes of patients with high-risk neuroblastoma have encouraged the search for new therapies. In the current study, the effect of the vitamin D analog 1alpha-hydroxyvitamin D2 (1alpha-OH-D2, doxercalciferol) was assessed in a mouse xenograft model of human neuroblastoma. Vitamin D receptor (VDR) expression levels in seven neuroblastoma cell lines were compared using real-time PCR. SK-N-AS cells, which express relatively high levels of VDR, were injected into the flanks of 60 mice. The mice were treated daily via oral gavage for 5 weeks with vehicle (control), 0.15 microg, or 0.3 microg of 1alpha-OH-D2. The animals were then euthanized, and tumors, sera, and kidneys were collected and analyzed. End tumor volumes were significantly smaller in both the 0.15 microg group (712.07 mm3, P = 0.0121) and 0.3 microg group (772.97 mm3, P = 0.0209) when compared to controls (1,681.75 mm3). In terms of toxicity, serum calcium levels were increased but mortality was minimal in both treatment groups. These results were similar to those previously described in the transgenic (LHbeta-Tag) and human xenograft (Y-79) models of retinoblastoma, a related tumor. In vitro cell viability studies of SK-N-AS and NGP cells, which represent two major human neuroblastoma subtypes that differ in their genetic abnormalities as well as their VDR expression levels, show that both are sensitive to calcitriol, the active metabolite of vitamin D3. In conclusion, the present study shows that 1alpha-OH-D2 can inhibit human neuroblastoma growth in vivo with relatively low toxicity. The safety of 1alpha-OH-D2 has been extensively studied; the drug is FDA-approved for the treatment of adult kidney patients, and Phase I/II trials have been conducted in adult oncology patients. There should not be major obstacles to starting Phase I and II clinical trials with this drug in pediatric patients with high-risk neuroblastoma.

Understanding Parents’ Approaches to Care and Treatment of Children With Cancer When Standard Therapy Has Failed

Purpose

To examine US and United Kingdom (UK) parents’ approaches to care and treatment when standard therapy has failed and consider implications for clinical practice.

Methods

We conducted a prospective, ethnographic study of parents, patients, and staff, including participant-observation; open-ended, semistructured interviews; and review of medical records at a US and UK pediatric oncology center. Thirty-four children (n = 17 US, 17 UK), whose disease had recurred with less than 30% chance of cure, were enrolled between March 2001 and June 2002 and followed until death (n = 11 US, 14 UK) or close of study in December 2005 (n = 6 US, 3 UK).

Results

There were no major differences between parents’ approaches in the US and UK despite differences in health care systems, institutions, and parents’ religion or ethnicity. All parents continued to have or request meetings with the oncologist and investigative procedures. No parent initiated discontinuation of cancer- or symptom-directed interventions. In 28 of 34 cases (13 US, 15 UK), parents continued to pursue cancer-directed therapies; in 16 of 28 cases (seven US, nine UK), parents initiated inquires beyond what was offered.

Conclusion

Understanding parents’ behavior requires attention to the reason and emotion they bring to decision making and their children's care, their unique responsibilities as parents, and what they learn throughout the illness. Parents do not see cancer-directed therapy and symptom-directed care as mutually exclusive, alternative approaches. Parents will not be constrained by what the oncologist offers. Physicians and parents discuss and negotiate care and treatment throughout the illness. Our findings suggest developing integrative care models incorporating cancer-directed, symptom-directed, and supportive care throughout the illness; they are most consistent with parents’ approaches and advances in pediatric oncology.

Epidemiology, Management and Treatment Outcome of Medulloblastoma in Singapore

Introduction: Medulloblastoma/primitive neuroectodermal tumour is the most common type of malignant brain tumour in children. Long-term survival rates have improved over the years with a combination of surgical, radiotherapeutic and chemotherapeutic treatment modalities in the developed world. This paper aims to analyse the epidemiology and outcome of medulloblastoma in Singapore and compare our results with those reported in the literature. Materials and Methods: A 9-year retrospective study was done using data reported to the Singapore Children’s Cancer Registry from June 1997 to June 2005. Only 39 children up to the age of 15 years diagnosed histologically with medulloblastoma or primitive neuroectodermal tumour arising from the cerebellum were included in the study. Follow-up data were collected up to June 2006 and analysed using SPSS v 13.0 software. Results: Medulloblastoma/primitive neuroectodermal tumour was the most common type of brain tumour, accounting for 40.7% of all brain tumours diagnosed in children in Singapore. The 5-year event-free survival rate was 44.5%, while the 5year overall survival rate was 51.5%. Nearly half (41%) of our patients had spinal metastasis at presentation and this was associated with a worse event-free survival (6.3% vs 71.9%, P = 0). Children under 36 months of age had a significantly poorer overall survival (28.8% vs 52.2%, P = 0.041). Conclusions: The outcome of medulloblastoma in Singapore was inferior to reported figures in the literature. We need to close identified gaps in care, like standardising assessment and treatment protocols, in order to improve our results. Research into molecular and genetic characteristics may also throw light on whether the disease is inherently more aggressive in our population. Key words: Medulloblastoma, Outcome, Singapore

Incidence of cancer in children residing in ten jurisdictions of the Mexican Republic: importance of the Cancer registry (a population-based study)

BACKGROUND

In 1996, Mexico started to register cases of childhood cancer. Here, we describe the incidence of cancer in children, residing in ten Mexican jurisdictions, who were treated by the Instituto Mexicano del Seguro Social (IMSS).

METHODS

New cases of childhood cancer, which were registered prospectively in nine principal Medical Centers of IMSS during the periods 1998-2000 (five jurisdictions) and 1996-2002 (five jurisdictions), were analyzed. Personnel were specifically trained to register, capture, and encode information. For each of these jurisdictions, the frequency, average annual age-standardized incidence (AAS) and average annual incidence per period by sex and, age, were calculated (rates per 1,000,000 children/years).

RESULTS

In total 2,615 new cases of cancer were registered, with the male/female ratio generally >1, but in some tumors there were more cases in females (retinoblastoma, germ cells tumors). The principal groups of neoplasms in seven jurisdictions were leukemias, central nervous system tumors (CNS tumors), and lymphomas, and the combined frequency for these three groups was 62.6 to 77.2%. Most frequently found (five jurisdictions) was the North American-European pattern (leukemias-CNS tumors-lymphomas). Eight jurisdictions had AAS within the range reported in the world literature. The highest incidence was found for children underless than five year of age. In eight jurisdictions, leukemia had high incidence (>50). The AAS of lymphomas was between 1.9 to 28.6. Chiapas and Guerrero had the highest AAS of CNS tumors (31.9 and 30.3, respectively). The frequency and incidence of neuroblastoma was low. Chiapas had the highest incidence of retinoblastoma (21.8). Germ-cell tumors had high incidence.

CONCLUSION

The North American-European pattern of cancers was the principal one found; the overall incidence was within the range reported worldwide. In general but particularly in two jurisdictions (Yucatán and Chiapas), it will be necessary to carry out studies concerning the causes of cancer in children. Due to the little that is known about the incidence of cancer in Mexican children, it will be necessary to develop a national program to establish a cancer registry for the whole of the country.

Trends in childhood cancer incidence: review of environmental linkages

Cancer in children is rare and accounts for about 1% of all malignancies. In the developed world, however, it is the commonest cause of disease-related deaths in childhood, carrying with it a great economic and emotional cost. Cancers are assumed to be multivariate, multifactorial diseases that occur when a complex and prolonged process involving genetic and environmental factors interact in a multistage sequence. This article explores the available evidence for this process, primarily from the environmental linkages perspective but including some evidence of the genetic factors.

Damage and recovery of the bone growth mechanism in young rats following 5-fluorouracil acute chemotherapy

Chemotherapy-induced bone growth arrest and osteoporosis are significant problems in paediatric cancer patients, and yet how chemotherapy affects bone growth remains unclear. This study characterised development and resolution of damage caused by acute chemotherapy with antimetabolite 5-fluorouracil (5-FU) in young rats in the growth plate cartilage and metaphyseal bone, two important tissues responsible for bone lengthening. In metaphysis, 5-FU induced apoptosis among osteoblasts and preosteoblasts on days 1-2. In growth plate, chondrocyte apoptosis appeared on days 5-10. Interestingly, Bax was induced prior to apoptosis and Bcl-2 was upregulated during recovery. 5-FU also suppressed cell proliferation on days 1-2. While proliferation returned to normal by day 3 in metaphysis, it recovered partially on day 3, overshot on days 5-7 and normalised by day 10 in growth plate. Histologically, growth plate heights decreased by days 4-5 and returned normal by day 10. In metaphysis, primary spongiosa height was also reduced, mirroring changes in growth plate thickness. In metaphyseal secondary spongiosa, a reduced bone volume was observed on days 7-10 as there were fewer but more separated trabeculae. Starting from day 4, expression of some cartilage/bone matrix proteins and growth factors (TGF-beta1 and IGF-I) was increased. By day 14, cellular activity, histological structure and gene expression had returned normal in both tissues. Therefore, 5-FU chemotherapy affects bone growth directly by inducing apoptosis and inhibiting proliferation at growth plate cartilage and metaphyseal bone; after the acute damage, bone growth mechanism can recover, which is associated with upregulated expression of matrix proteins and growth factors.

Induction of cytolytic T lymphocytes against pediatric solid tumors in vitro using autologous dendritic cells pulsed with necrotic primary tumor

PURPOSE

Effective and generally applicable methods for generating cancer vaccines in children have not been defined. Dendritic cells (DCs) are the most potent professional antigen-presenting cells capable of activating primary cytolytic T cells. We tested the ability of DCs generated from pediatric patients' peripheral blood monocytes and pulsed with a necrotic tumor to activate autologous tumor-specific cytolytic T cells.

METHODS

Tumor and peripheral blood cells were obtained from pediatric patients undergoing biopsy or resection for advanced solid tumors according to an institutional research board-approved protocol and after acquiring informed consent from them. To generate DCs, we treated peripheral blood monocytes with granulocyte-macrophage colony stimulating factor and interleukin (IL)-4. Maturation was induced with a cytokine cocktail (CC) containing tumor necrosis factor-alpha, IL-6, IL-1beta, and prostaglandin E2. The DC phenotype was assayed using flow cytometry. Tumor necrosis was induced by exposure to UV-B irradiation (1000 mJ). Dendritic cells pulsed with a UV-B-treated primary tumor and matured with CC were used to stimulate autologous peripheral blood lymphocytes weekly. Tumor-specific cytolytic activity was assayed using 4-hour 51Cr release.

RESULTS

Peripheral blood monocytes isolated from pediatric patients differentiated into immature DCs (CD14-, MHCII+ [major histocompatibility complex], CD80(low), CD86(low)) in the presence of granulocyte-macrophage colony stimulating factor and IL-4. Cytokine cocktail induced maturation of DCs, as characterized by increased expressions of MHCII, CD83, CD80, and CD86. Patients' peripheral blood lymphocytes stimulated in vitro with DCs loaded with a necrotic primary tumor and matured with CC specifically lysed autologous neuroblastoma in 7 of 9 patients.

CONCLUSION

Dendritic cells generated from the peripheral blood of children with advanced solid tumors and pulsed with a necrotic primary tumor undergo maturation and effectively stimulate autologous tumor-specific cytolytic T cells in vitro. We describe a simple method for generating a vaccine capable of activating cytotoxic T cells against pediatric solid tumors that does not require the genetic identification of tumor-associated antigens.

Peripheral neuroblastic tumours in eastern Denmark 1972?2002

The peripheral neuroblastic tumour group includes neuroblastoma, ganglioneuroblastoma and ganglioneuroma. Neuroblastoma is the most common extracranial solid tumour of childhood. We have evaluated the histological presentation, MYCN gene status, and clinical course of peripheral neuroblastic tumours diagnosed and treated in eastern Denmark from 1972-2002. 125 patients were diagnosed with peripheral neuroblastic tumour during this 30-year period. The histological material was reviewed and classified into three categories in accordance with the Shimada system: unfavourable histology, favourable histology, and benign tumours. MYCN status was determined by fluorescent in situ hybridization (FISH) on paraffin sections from the primary tumour. Clinical information was obtained from hospital records. Diagnostic likelihood ratios in the two groups were calculated to compare the ability of MYCN status and histological classification to predict 5-year outcome. 41 tumours showed unfavourable histology, 30 tumours showed favourable histology, 11 were benign, and 43 were unclassifiable due to limited amounts of primary tumour, bad preservation or inaccessibility of the primary tumour necessitating metastatic tumour biopsy for diagnosis. Unfavourable histology was associated with widespread disease (p<0.001). The overall 5-year survival rate was 45%, which correlates well with the European survival rate reported for this time period. The 5-year survival rate in the unfavourable group was 30% as compared to 100% in the favourable histology group (p<0.001). The survival rate in the unclassifiable group was 13%. 26% of the neuroblastomas were MYCN amplified. MYCN amplification was associated with undifferentiated histology, a histological subtype of the unfavourable histology group (p<0.001). For unfavourable histology the positive diagnostic likelihood ratio was 2.9 as compared to 4.7 for MYCN amplification. The study has confirmed the prognostic significance of the Shimada system in the peripheral neuroblastic tumour group in a retrospective material, and has also demonstrated the prognostic superiority of MYCN compared to histological classification, thus reducing the necessary amounts of tumour tissue.

Production of the first offspring from oocytes derived from fresh and cryopreserved pre-antral follicles of adult mice

Although mammalian ovaries contain hundreds of thousands of pre-antral follicles, fewer than 1% of these reach maturity and ovulation. Obtaining immature eggs from the pre-antral follicles of ovarian tissue could increase the possibility of preserving fertility in women undergoing anti-cancer treatment, and in women who wish to delay pregnancy and child raising until they are older. This study reports the birth of 10 healthy mouse pups derived from oocytes obtained from pre-antral follicles after adult ovary tissue cryopreservation and allotransplantation. High in-vitro maturation (55.1%), fertilization (76.3%) and cleavage (98.3%) rates were achieved using these oocytes, and there was no significant difference between the vitrified and control samples except in maturation rate (55.1 versus 72.8%, P < 0.05). After an ultra-rapid vitrification procedure, the warmed tissue fragments were transplanted beneath the kidney capsule of severe combined immunodeficient mice for onward in-vivo culture. Within 10 days of culture, 138 full size oocytes developed from the 456 transplanted pre-antral follicles. In-vivo growth of follicles was followed by in-vitro oocyte maturation, in-vitro fertilization and subsequent embryo transfer, leading to the birth of 10 healthy pups. These results may lead to increasing the possibility of preserving fertility by cryopreservation of ovarian tissue.

Risk factors for acute leukemia in children: a review

Although overall incidence is rare, leukemia is the most common type of childhood cancer. It accounts for 30% of all cancers diagnosed in children younger than 15 years. Within this population, acute lymphocytic leukemia (ALL) occurs approximately five times more frequently than acute myelogenous leukemia (AML) and accounts for approximately 78% of all childhood leukemia diagnoses. Epidemiologic studies of acute leukemias in children have examined possible risk factors, including genetic, infectious, and environmental, in an attempt to determine etiology. Only one environmental risk factor (ionizing radiation) has been significantly linked to ALL or AML. Most environmental risk factors have been found to be weakly and inconsistently associated with either form of acute childhood leukemia. Our review focuses on the demographics of childhood leukemia and the risk factors that have been associated with the development of childhood ALL or AML. The environmental risk factors discussed include ionizing radiation, non-ionizing radiation, hydrocarbons, pesticides, alcohol use, cigarette smoking, and illicit drug use. Knowledge of these particular risk factors can be used to support measures to reduce potentially harmful exposures and decrease the risk of disease. We also review genetic and infectious risk factors and other variables, including maternal reproductive history and birth characteristics.

Investigating childhood leukemia in Churchill County, Nevada

BACKGROUND

Sixteen children diagnosed with acute leukemia between 1997 and 2002 lived in Churchill County, Nevada, at the time of or before their illness. Considering the county population and statewide cancer rate, fewer than two cases would be expected.

OBJECTIVES

In March 2001, the Centers for Disease Control and Prevention led federal, state, and local agencies in a cross-sectional, case-comparison study to determine if ongoing environmental exposures posed a health risk to residents and to compare levels of contaminants in environmental and biologic samples collected from participating families.

METHODS

Surveys with more than 500 variables were administered to 205 people in 69 families. Blood, urine, and cheek cell samples were collected and analyzed for 139 chemicals, eight viral markers, and several genetic polymorphisms. Air, water, soil, and dust samples were collected from almost 80 homes to measure more than 200 chemicals.

RESULTS

The scope of this cancer cluster investigation exceeded any previous study of pediatric leukemia. Nonetheless, no exposure consistent with leukemia risk was identified. Overall, tungsten and arsenic levels in urine and water samples were significantly higher than national comparison values; however, levels were similar among case and comparison groups.

CONCLUSIONS

Although the cases in this cancer cluster may in fact have a common etiology, their small number and the length of time between diagnosis and our exposure assessment lessen the ability to find an association between leukemia and environmental exposures. Given the limitations of individual cancer cluster investigations, it may prove more efficient to pool laboratory and questionnaire data from similar leukemia clusters.

Childhood soft tissue sarcomas incidence and survival in European children (1978-1997): report from the Automated Childhood Cancer Information System project

This population-based study is based on 5802 cases of soft tissue sarcomas (STS) in children aged 0-14 years extracted from the database of the Automated Childhood Cancer Information System (ACCIS) and registered in population-based cancer registries in Europe for the period 1978-1997. STS represent almost 8% of neoplasms in children, almost half of whom are less than 5 years at diagnosis. Rhabdomyosarcoma is the most frequent childhood STS (50%). During 1988-1997 the age-standardised incidence of STS in Europe was 9.1 per million children, lowest in the West and East and highest in the North. The incidence of STS increased almost 2% per year over the period 1978-1997, attributable mostly to increase in genito-urinary rhabdomyosarcoma. Prognosis of children with STS was related to age and site of tumour. Five-year survival of children with STS increased from 46% in 1978-1977 to 66% in 1993-1997, reaching 74% in the North for those diagnosed in 1993-1997. This improvement is ascribed to therapy advances.

Today's epidemics in children: possible relations to environmental pollution and suggested preventive measures

BACKGROUND

Facts and hypotheses on the relationship between some children's diseases or disorders and external stressors during the developmental stage of a child, both prenatally and postnatally are described in literature. In this paper the following changes in patterns and causes of the main childhood illnesses are summarized and recommendations for actions are made. Prematurity. Intra-uterine growth restriction. Testicular dysgenesis syndrome. Type I and Type II diabetes. Asthma, atopy and hay fever. Autism. Attention deficit hyperactivity disorder (ADHD). Learning disabilities. Cancer. Obesity. Hearing problems.

RESULTS

Literature provides a growing amount of information on changing patterns in childhood diseases.

CONCLUSIONS

The following recommendations for action are formulated: Immediate research on endocrine disrupters in relation to prematurity. Diabetes: avoid Maillard Compounds in liquid baby food and in food in general: promote breastfeeding. Asthma: avoid exposure to smoking, the use of chemical household products, dioxin and dioxin-like chemicals, and avoid air pollution with high levels of particulate matter, especially around conception, during pregnancy and in the first years of life. Autism: more research on incidence and causes. ADHD and learning disabilities: more research on prevalence and causes. Preventions: 1) preconception counselling to avoid potentially harmful substances; 2) controlling and further lowering levels of polychlorinated biphenyls, lead and methyl mercury. Cancer: promote breastfeeding, carry out research into effects of foetal exposure to internal fission-product radionuclides. Obesity: stop smoking in pregnancy, avoid parental obesity, longer night sleep. Hearing problems: lower noise levels in discothèques, promote the day-evening-night level to avoid noise (longer night sleep).

Cryopreservation of the ovary by vitrification as an alternative to slow-cooling protocols

OBJECTIVE

To study the thermal properties of a cryoprotectant solution, called VS4, and of VS4-impregnated whole sheep ovaries with pedicle.

DESIGN

Physical and experimental animal study.

SETTING

Academic research environment.

ANIMAL(S)

Five- to 6-month-old ewes.

INTERVENTION(S)

Thermal properties on cooling of a cryoprotectant solution called VS4 were measured by differential scanning calorimetry. VS4 contains 2.75 mol/L dimethyl sulfoxide, 2.76 mol/L formamide, and 1.97 mol/L propylene glycol. Whole sheep ovaries were collected at the slaughterhouse and prepared for a vitrification procedure. Cortex and vessels underwent histologic examination before and after vitrification, and the thermal properties of VS4-impregnated ovarian cortex were then studied.

MAIN OUTCOME MEASURE(S)

Critical cooling rates (V(ccr)), vitreous transition temperature (Tg), end-of-melting temperature (Tm), follicle viability assessment by trypan blue test, and histologic examination of ovary and vessel structure.

RESULT(S)

The critical cooling rate (V(ccr)) of VS4 solution was estimated to be 14.3 +/- 1.1 degrees C/min. Its vitreous transition temperature (Tg) was -125.2 +/- 0.2 degrees C, and its end-of-melting temperature (Tm) -34.3 +/- 0.1 degrees C. Following our vitrification procedure, immediate follicle viability was 61.4% +/- 2.2%. The percentage of normal primordial follicles remaining after vitrification was 48% +/- 3.8%. The V(ccr) of VS4-impregnated cortex could not be determined because of the quantity of ice forming as of the top programmed cooling rate (-300 degrees C/min). The mean ovarian cortex cooling rate actually attained experimentally during vitrification was -342.9 +/- 49.6 degrees C/min.

CONCLUSION(S)

Vitrification of entire organs, such as ovaries, is a great challenge in cryobiology and reproductive medicine. Physical studies seem indispensable for progress with this technique. Thus, our ovarian perfusion procedure needs improving to enhance ovarian cortex impregnation and bring down the V(ccr) rate in both tissue and VS4 solution.

Induction of sarcomas by a single subcutaneous injection of 7,12-dimethylbenz[a]anthracene into neonatal male Sprague-Dawley rats: histopathological and immunohistochemical analyses

Animal experiments have shown that carcinogenicity of chemicals is higher in fetal or neonatal periods than adult. We investigated sensitivities to a carcinogen in peri-neonatal rats with a model of sarcomas-induction by a subcutaneous injection of chemo-carcinogen that has rarely done in neonatal rats. Neonatal male SD rats were injected with 7,12-DMBA 10, 100, and 500 microg, which resulted in sarcomas-induction in 0, 62, and 94% of rats. Male SD rats were injected with DMBA 500 microg at 0, 3, 7, 14, and 21 days, which resulted in sarcomas-induction in 94, 70, 64, 50, and 44% of rats. Although the induced sarcomas were occasionally in mixed morphological feature as previous reports for sarcomas of rat, each was immunohistochemically in almost monotonous pattern, and classification was feasible. The incidence of rhabdomyosarcomas was higher in rats neonatally injected with a higher dose of DMBA than a lower dose, and in rats injected at peri-neonatal periods than later periods. In histological observations for the site of injection before overt sarcomas develop, clusters of atypical mesenchymal cells emerged as previous studies, but also those were immunohistochemically differentiated into rhabdomyocytes and other mesenchymal cells. We consider these findings may contribute a little to elucidation of process of sarcomas-induction in rats.

Childhood central nervous system tumours – incidence and survival in Europe (1978–1997): Report from Automated Childhood Cancer Information System project

This paper describes the incidence and survival of childhood central nervous system (CNS) tumours in Europe for the period 1978-1997. A total of 19,531 cases, aged 0-14 years, from the ACCIS database were analysed by five regions: the British Isles, East, North, South, and West. Overall age-standardised incidence rate (ASR) of CNS tumours in Europe (1988-1997) was 29.9 per million, with the highest rates in the North. Astrocytoma (ASR=11.8), primitive neuroectodermal tumours (PNET) (ASR=6.5) and ependymoma (ASR=3.4) were the most frequent types. Incidence increased significantly during 1978-1997, on average by 1.7% per year. Diagnostic methods may partially explain incidence rates and trends, although a role of variations in risk factors cannot be excluded. Overall 5-year survival was 64% and varied between 72% in the North and 53% in the East. PNET had the poorest prognosis (49%) and astrocytoma the best (75%). Survival has improved by 29% since late 1970s. The positive trends were seen in all regions, although the interregional differences persisted, as a reflection of the different healthcare systems.

Interpreting Cancer Trends

The interpretation of cancer incidence trends is complicated by short-term random variation, artifactual fluctuations introduced by screening, changes in diagnosis or disease classification, completeness of reporting, and by the multiplicity of factors that may affect risk for specific cancer sites. We analyzed trends in 56 different cancer sites and subsites in the U.S. SEER registries in the period 1975-2002 using join-point analysis. The increase in cancer incidence for all sites combined that became evident with the inception of the SEER registries in the mid-1970s has abated since the early 1990s. Among the 15 most common cancer sites in men, sites with increasing incidence rates during the most recent time period include melanoma of the skin and cancers of the prostate, kidney and renal pelvis (kidney), and esophagus. Among women, incidence rates are increasing for leukemia, non-Hodgkin's lymphoma, melanoma, and cancers of the breast, thyroid, urinary bladder, and kidney. Incidence rates for all childhood cancers combined increased 0.6% per year from 1975 to 2002. Cancer mortality rates have decreased in the United States since 1991 in both men and in women; site-specific death rates have decreased in the most recent time period for 12 of the top 15 cancer sites in men and 9 of the top 15 cancer sites in women. Similar trends in cancer incidence and mortality have been reported in other industrialized countries. Possible reasons for these trends are discussed.

Environmental genotoxicants/carcinogens and childhood cancer: Bridgeable gaps in scientific knowledge

Cancer in children is a major concern in many countries. An important question is whether these childhood cancers are caused by something, or are just tragic random events. Causation of at least some children's cancers is suggested by direct and indirect evidence, including epidemiological data, and animal studies that predict early life sensitivity of humans to carcinogenic effects. Candidate risk factors include genotoxic agents (chemicals and radiation), but also diet/nutrition, and infectious agents/immune responses. With regard to likelihood of risks posed by genotoxicants, there are pros and cons. The biological properties of fetuses and infants are consistent with sensitivity to preneoplastic genotoxic damage. Recent studies of genetic polymorphisms in carcinogen-metabolizing enzymes confirm a role for chemicals. On the other hand, in numerous epidemiological studies, associations between childhood cancers and exposure to genotoxicants, including tobacco smoke, have been weak and hard to reproduce. Possibly, sensitive genetic or ontogenetic subpopulations, and/or co-exposure situations need to be discovered to allow identification of susceptible individuals and their risk factors. Among the critical knowledge gaps needing to be bridged to aid in this effort include detailed tissue and cellular ontogeny of carcinogen metabolism and DNA repair enzymes, and associations of polymorphisms in DNA repair enzymes with childhood cancers. Perinatal bioassays in animals of specific environmental candidates, for example, benzene, could help guide epidemiology. Genetically engineered animal models could be useful for identification of chemical effects on specific genes. Investigations of interactions between factors may be key to understanding risk. Finally, fathers and newborn infants should receive more attention as especially sensitive targets.

Progress in the development of childhood cancer therapy

Despite the continuous improvement of cancer treatment protocols, altered testicular function and infertility frequently represent major adverse effects of oncologic treatments. Thus, strong efforts are needed to avoid or at least to reduce these complications that are particularly relevant in young men without offspring. Furthermore in the last years, concerns have been raised about the possible mutagenic effect of chemotherapy on sperm. Alkylating agents are frequently and successfully used in the treatment of paediatric tumors despite their well-known gonadotoxic effect. While gonadal toxicity of cyclophosphamide has been well demonstrated, little and conflicting data are reported about the effects on testicular function of ifosfamide. The aim of this study was to compare long-term effects of ifosfamide versus cyclophosphamide based therapies, on testicular function, fertility and sperm aneuploidies in a group of 33 young males survivors of childhood cancer. Patients who had received cyclophosphamide showed a severe gonadal failure characterized by reduced testicular size, very low sperm count and some degree of Leydig cell impairment. On the contrary, in subjects who had received ifosfamide all parameters of testicular function including sperm aneuploidies were in the normal range, despite of different dose, protocol of infusion and pubertal stage at treatment. In conclusion, our results confirm data of literature reporting the high gonadal toxicity of cyclophosphamide and suggest that ifosfamide treatment seems to be safer for testicular function and fertility.

Gene expression profiling reveals intrinsic differences between T-cell acute lymphoblastic leukemia and T-cell lymphoblastic lymphoma

BACKGROUND

T-cell acute lymphoblastic leukemia (T-ALL) and T-cell lymphoblastic lymphoma (T-LL) and are often thought to represent a spectrum of a single disease. The malignant cells in T-ALL and T-LL are morphologically indistinguishable, and they share the expression of common cell surface antigens and cytogenetic characteristics. However, despite these similarities, differences in the clinical behavior of T-ALL and T-LL are observed.

PROCEDURE

We analyzed the gene expression profiles of T-ALL and T-LL samples obtained from Children's Oncology Group (COG) tumor banks using DNA arrays. Immunohistochemistry was also performed to validate the expression of selected targets.

RESULTS

Unsupervised hierarchical clustering of all samples showed complete segregation of T-ALL and T-LL into distinct clusters. Next, we identified the top 201 genes that best differentiated T-ALL from T-LL using significance analysis of microarrays (SAM), a supervised statistical approach. Genes representing several functional groups were differentially expressed in T-LL and T-ALL. Prediction analysis of microarrays (PAM) identified a subset of genes, which accurately classified all 19 T-ALL and T-LL samples with an overall misclassification error rate of 0. Immunohistochemical validation of protein expression of selected genes identified by microarray analysis confirmed overexpression of MLL-1 in T-LL tumor cells compared to T-ALL and CD47 in T-ALL tumors cells when compared to T-LL.

CONCLUSIONS

Despite significant similarities between the malignant T-cell precursors, clear differences in the gene expression profiles were observed between T-ALL and T-LL implying underlying differences in the biology of the two entities.

Increasing incidence of childhood tumours of the central nervous system in Denmark, 1980-1996

The registered incidence rate of childhood central nervous system (CNS) tumours has increased in several countries. It is uncertain whether these increases are biologically real or owing to improved diagnostic methods. We explored the medical records of 626 CNS tumours diagnosed in Danish children between 1980 and 1996. Population-based registers were used to extract data on mortality and background population. Temporal patterns were analysed by regression techniques. Most tumours were verified by computed tomography (78%) or magnetic resonance imaging (14%). Overall, the incidence rate increased by 2.9% per year (95% confidence interval (CI): 1.3;4.5) and the mortality rate increased by 1.4% per year (95% CI: −0.4;3.3). Among children aged 0–4 years, the survival rate after diagnosis remained almost unchanged, whereas among children aged 5–14 years, the 10-year survival rate improved from 59 to 74%. These data suggest that the incidence rate of CNS tumours among Danish children has truly increased, although alternative explanations cannot be excluded.

Trends in childhood disease

Child mortality has declined remarkably during the last decades. While neonatal disorders, diarrhoea, pneumonia, and malaria as well as being underweight account for most of the child deaths worldwide, children's health discussions in Europe and the USA focus on other issues such as asthma, neurodevelopmental disorders, male genital malformations, and childhood cancer. There is clear evidence of increasing rates of asthma in various countries during the last decades, although rates in some countries may now have stabilised or even decline as recent UK data indicate. Although an increase in the frequency of neurodevelopmental disorders such as autism and attention deficit disorder has frequently been discussed, the limited data in this field does not justify such a conclusion. While geographic heterogeneity regarding reproductive outcomes is apparent, global trends have not been identified. Interpretation of the available information on asthma, neurodevelopmental disorders and reproductive outcomes is hampered by inconstant diagnostic criteria over place and time and the lack of good and comprehensive population-based surveillance data, which makes it impossible to ascertain trends in actual disease frequency. Data indicate that developed countries have a gradually increasing incidence in leukaemia with a corresponding drop in the incidence of lymphoma. Increases in brain tumour frequency may be related to the development and wide application of new diagnostic capabilities, rather than a true change in the incidence of malignant disease. With a better prognosis for childhood cancer survival, secondary cancers following chemotherapy appear to be increasing. A wide range of environmental factors is thought to have an impact on children's health. These factors include nutrition (protein, vitamins, antioxidants), lifestyle and behaviour choices such as tobacco and alcohol use, parental health, socio-economic status, choice of living environment (urban versus rural, etc.), and parent-sibling behaviour. From the available data, no general conclusions on the contribution of specific chemicals can be drawn.

Current developments in radiotherapy for paediatric brain tumours

This review summarises current developments in radiation oncology and how they impact on the management of children with brain tumours. Improved understanding of radiobiology has led to attempts to improve the therapeutic ratio with hyperfractionated radiotherapy. Recent advances in planning and delivery of radiotherapy, including three-dimensional conformal radiotherapy, intensity modulated radiotherapy, and proton therapy allow a more precise localisation of the maximum dose region with maximum sparing of normal brain. Increasingly interactions between drugs and radiotherapy are exploited, but it is important to evaluate toxicity of combined modality therapy. The introduction of models to predict the impact of radiotherapy dose-volume parameters on long-term neuropsychological function will hopefully lead to further benefit with respect to sparing of normal tissue morbidity.

Second malignant neoplasms following the treatment of brain tumors in children

We investigated retrospectively 992 children with central nervous system tumors who were treated at our center between 1970 and 2004. All of the patients were treated by surgery, chemotherapy, and/or radiotherapy. Six patients developed second malignant neoplasms, and their clinical and histopathologic characteristics are reviewed in this article. The second malignant neoplasms were diagnosed as non-Hodgkin lymphoma, myelodysplastic syndrome, basal cell carcinoma, malignant melanoma, Kaposi sarcoma, and high-grade neuroectodermal tumor. The initial diagnoses were ependymoblastoma in one, medulloblastoma in three, and low-grade astrocytoma in two patients. The median latency time was 3.03 years (range 0.39-22.93 years). The outcome varied according to the histopathologic type of the second tumor. The patients who developed non-Hodgkin lymphoma and myelodysplastic syndrome died of progressive disease. The patients with second skin neoplasms are alive as of the time of this writing. The patient with Kaposi sarcoma developed one of the rare reported second malignant neoplasms following a primary brain tumor in childhood. A wide spectrum of second malignant neoplasms was detected after treatment of primary brain tumors with surgery, radiotherapy, and chemotherapy. Long-term follow-up is therefore necessary for the child who has survived a primary central nervous system tumor.

Acute ovarian failure in the childhood cancer survivor study

CONTEXT

Defined as the loss of ovarian function within 5 yr of diagnosis, acute ovarian failure (AOF) is known to develop in a subset of survivors of pediatric and adolescent cancers. Its precise incidence is unknown, and data concerning its risk factors are limited.

OBJECTIVE

Our objective was to determine the incidence of and patient/treatment factors associated with AOF in a large cohort of pediatric cancer survivors.

DESIGN AND SETTING

We conducted a retrospective cohort, multicenter study.

PATIENTS

Female participants from the Childhood Cancer Survivor Study who were greater than 18 yr of age were considered for inclusion. We excluded survivors who received cranial irradiation at doses of more than 3000 cGy, those with hypothalamic/pituitary tumors, and survivors who underwent bilateral oophorectomy. Survivors who reported never menstruating or who had ceased having menses within 5 yr after their cancer diagnosis were considered to have AOF.

MAIN OUTCOME

We assessed incidence and risk factors for AOF.

RESULTS

Of a total of 3390 eligible survivors, 215 cases (6.3%) developed AOF. Survivors with AOF were older at diagnosis and more likely to have been diagnosed with Hodgkin's lymphoma or to have received abdominal or pelvic radiotherapy than survivors without AOF. Among survivors with AOF, 116 (54%) had received at least 1000-cGy ovarian irradiation. In a multivariable logistic regression model, increasing doses of ovarian irradiation, exposure to procarbazine, and exposure to cyclophosphamide at ages 13-20 yr were independent risk factors for AOF.

CONCLUSIONS

AOF develops in a small subset of survivors, especially those treated with at least 1000-cGy ovarian radiation. These results will facilitate patient counseling and selection of candidates for newer fertility preservation techniques.

Bayesian methods for early detection of changes in childhood cancer incidence: Trends for acute lymphoblastic leukaemia are consistent with an infectious aetiology

Published data on time trends in the incidence of childhood leukaemia show inconsistent patterns, with some studies showing increases and others showing relatively stable incidence rates. Data on time trends in childhood cancer incidence from the Childhood Cancer Registry of Piedmont, Italy were analysed using two different approaches: standard Poisson regression and a Bayesian regression approach including an autoregressive component. Our focus was on acute lymphoblastic leukaemia (ALL), since this is hypothesised to have an infectious aetiology, but for purposes of comparison we also conducted similar analyses for selected other childhood cancer sites (acute non-lymphoblastic leukaemia (AnLL), central nervous system (CNS) tumours and neuroblastoma (NB)). The two models fitted the data equally well, but led to different interpretations of the time trends. The first produced ever-increasing rates, while the latter produced non-monotonic patterns, particularly for ALL, which showed evidence of a cyclical pattern. The Bayesian analysis produced findings that are consistent with the hypothesis of an infectious aetiology for ALL, but not for AnLL or for solid tumours (CNS and NB). Although sudden changes in time trends should be interpreted with caution, the results of the Bayesian approach are consistent with current knowledge of the natural history of childhood ALL, including a short latency time and the postulated infectious aetiology of the disease.

Lymphoma incidence patterns by WHO subtype in the United States, 1992-2001

Because the causes of most lymphoid neoplasms remain unknown, comparison of incidence patterns by disease subtype may provide critical clues for future etiologic investigations. We therefore conducted a comprehensive assessment of 114,548 lymphoid neoplasms diagnosed during 1992-2001 in 12 Surveillance, Epidemiology, and End Results (SEER) registries according to the internationally recognized World Health Organization (WHO) lymphoma classification introduced in 2001. Cases coded in International Classification of Diseases for Oncology, Second Edition (ICD-O-2), were converted to ICD-O-3 for WHO subtype assignment. Age-specific and age-adjusted rates were compared by sex and race (white, black, Asian). Age-adjusted trends in incidence were estimated by sex and race using weighted least squares log-linear regression. Diverse incidence patterns and trends were observed by lymphoid neoplasm subtype and population. In the elderly (75 years or older), rates of diffuse large B-cell lymphoma (DLBCL) and follicular lymphoma increased 1.4% and 1.8% per year, respectively, whereas rates of chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) declined 2.1% per year. Although whites bear the highest incidence burden for most lymphoid neoplasm subtypes, most notably for hairy cell leukemia and follicular lymphoma, black predominance was observed for plasma cell and T-cell neoplasms. Asians have considerably lower rates than whites and blacks for CLL/SLL and Hodgkin lymphoma. We conclude that the striking differences in incidence patterns by histologic subtype strongly suggest that there is etiologic heterogeneity among lymphoid neoplasms and support the pursuit of epidemiologic analysis by subtype.

Cancer incidence in the age range 0–34 years: Historical and actual status in Denmark

On the basis of 55 years of continuous cancer registration in Denmark, we present cancer incidence rates, time trends and birth cohort analyses for persons aged 0-34 years. The group of 40,750 cancer patients showed a substantial over-representation of males aged 1-24 years. The cancer pattern among young (15-34 years) men was dominated by testicular cancer (35%), lymphomas (14%) and tumors of the brain (13%), while the pattern among young women was governed by invasive cervical cancer (19%), malignant melanoma (15%) and cancer of the breast (12%). In this age range, a positive time trend was seen after 1970, equivalent to average annual percentage increases of 1.9% for men and 1.8% for women, due mainly to markedly increasing trends for testicular cancer, malignant melanoma, brain tumors, thyroid cancer, skin carcinomas and skin sarcoma among men, and for brain tumors, non-Hodgkin lymphoma, malignant melanoma, skin carcinomas and thyroid cancer among women. We saw no clear time trend for breast cancer among women. The cancer pattern among children (0-14 years) was similar to that reported for other white populations.

Childhood leukemia, electric and magnetic fields, and temporal trends

During the past 25 years concern has been raised about the possible health effects of extremely low frequency (ELF) electric and magnetic fields (EMFs), particularly regarding childhood leukemia. Comparison of changes in electricity consumption (a surrogate for exposure) to changes in childhood-leukemia rates, known as ecologic correlation, have been used to argue both for and against the association between magnetic fields and childhood leukemia. In this paper we explore what can be learned from such an ecologic approach. We first examine separately the evidence on trends in exposure to EMFs and on trends in leukemia rates, and then compare the two. Both incidence rates and exposures have increased, but there are so many approximations and assumptions involved in connecting the two trends that we cannot regard the ecologic evidence as providing any meaningful evidence for or against a causal link.

Acute and delayed nausea and emesis control in pediatric oncology patients

BACKGROUND

To the authors' knowledge there is little information available regarding the effectiveness of standard antiemetic therapy among cancer patients who receive emetogenic chemotherapy in clinical practice, especially in the pediatric population. The current study was undertaken to determine the effectiveness of standard antiemetic interventions among children receiving emetogenic chemotherapy.

METHODS

The authors conducted a retrospective review of antiemetic surveys for children who received emetogenic chemotherapy. Patients and/or their parents were surveyed for acute and delayed nausea and emesis after each course of emetogenic chemotherapy. The survey consisted of validated measures of the severity of nausea and emesis. Complete protection (CP) rates were calculated for each chemotherapy regimen during both the acute and delayed phases and also by gender and age group (ages birth-3 yrs, 4-11 yrs, and 12-20 yrs). Antiemetic therapy consisted of intravenous ondansetron administered once daily during chemotherapy either alone (for moderately emetogenic chemotherapy) or in combination with dexamethasone (for severely emetogenic chemotherapy).

RESULTS

In total, 224 different patients completed 1256 surveys. CP from both acute and delayed nausea and emesis was more likely in the children ages birth-3 years than in older children. For moderately emetogenic regimens, nausea and emesis in the acute and delayed phases were controlled well. Among severely emetogenic chemotherapy regimens, 7 of 12 different regimen types had CP rates < 50% in either the acute phase or the delayed phase. CP rates were particularly low for cisplatin-based and cyclophosphamide-based regimens.

CONCLUSIONS

Nausea and emesis remain significant problems among children who receive emetogenic chemotherapy. CP rates were associated significantly with patient age, and higher rates were observed among very young children.

Cancer Surveillance Research: a Vital Subdiscipline of Cancer Epidemiology

Public health surveillance systems relevant to cancer, centered around population-based cancer registration, have produced extensive, high-quality data for evaluating the cancer burden. However, these resources are underutilized by the epidemiology community due, we postulate, to under-appreciation of their scope and of the methods and software for using them. To remedy these misperceptions, this paper defines cancer surveillance research, reviews selected prior contributions, describes current resources, and presents challenges to and recommendations for advancing the field. Cancer surveillance research, in which systematically collected patient and population data are analyzed to examine and test hypotheses about cancer predictors, incidence, and outcomes in geographically defined populations over time, has produced not only cancer statistics and etiologic hypotheses but also information for public health education and for cancer prevention and control. Data on cancer patients are now available for all US states and, within SEER, since 1973, and have been enhanced by linkage to other population-based resources. Appropriate statistical methods and sophisticated interactive analytic software are readily available. Yet, publication of papers, funding opportunities, and professional training for cancer surveillance research remain inadequate. Improvement is necessary in these realms to permit cancer surveillance research to realize its potential in resolving the growing cancer burden.

Restoration of ovarian endocrine function by ovarian transplantation

Cancer treatment can cause changes in sex hormone production, premature ovarian failure and infertility. As survival rates for young cancer patients improve, protection against iatrogenic infertility caused by chemotherapy or radiotherapy assumes a higher priority.

AMOR: a proposed cooperative effort to improve outcomes of childhood cancer in Central America

The dramatic reduction of pediatric cancer mortality rates has been one of the greatest accomplishments of contemporary medicine. About 80% of children with cancer are now expected to be cured by current therapies. However, most of the world's children have no access to cancer treatment. The translation of effective pediatric cancer therapies to impoverished regions of the world presents an enormous challenge to the health care profession. Over the past 20 years, efforts have been under way to extend adequate cancer treatment to an increasing number of children in developing countries. These initiatives, collectively designated "twinning programs," consist essentially of a partnership between a pediatric cancer unit in a developing country and a group of health care providers in the developed world. Here we review the twinning programs that have been implemented in Central America, discuss their impact on the development of local resources and the outcome of childhood cancer, and propose a collaborative research initiative aimed at improving the international dissemination of progress in pediatric hematology-oncology.

Detecting small-area similarities in the epidemiology of childhood acute lymphoblastic leukemia and diabetes mellitus, type 1: a Bayesian approach

Childhood acute lymphoblastic leukemia and diabetes mellitus, type 1, have common epidemiologic and etiologic features, including correlated international incidence and associations with infections. The authors examined whether the diseases' similar large-scale distributions are reflected in small geographic areas while also examining the influence of sociodemographic characteristics. Details of 299 children (0-14 years) with acute lymphoblastic leukemia and 1,551 children with diabetes diagnosed between 1986 and 1998 were extracted from two registers in Yorkshire, United Kingdom. Standardized incidence ratios across 532 electoral wards were compared using Poisson regression, confirming significant associations between population mixing and the geographic heterogeneity of both conditions. Bayesian methods analysis of spatial correlation between diseases by modeling a bivariate outcome based on their standardized incidence ratios was applied; spatial and heterogeneity components were included within a hierarchical random effects model. A positive correlation between diseases of 0.33 (95% credible interval: -0.20, 0.74) was observed, and this was reduced after control for population mixing (r = 0.18), population density (r = 0.14), and deprivation (r = 0.06). The Bayesian approach showed a modest but nonsignificant joint spatial correlation between diseases, only partially suggesting that the risk of both was associated within some electoral wards. With Bayesian methodology, population mixing remained significantly associated with both diseases. The links between diabetes and acute lymphoblastic leukemia observed for large regions are weaker for small areas. More powerful replications are needed for confirmation of these findings.