Intracranial non-germinomatous germ cell tumors in children and adolescents: how can the experience from an uppermiddle-income country contribute to the worldwide effort to improve outcomes?

Background: Non-germinomatous germ cell tumors (NGGCT) accounts for one third of intracranial GCT. While the germinoma group have an excellent overall survival, the standard of practice for children with NGGCT is still under evaluation. Aims: Describe the results of the of the Brazilian consortium protocol. Methods: Since 2013, 15 patients with a diagnosis of NGGCT by histopathology and/or serum/cerebrospinal fluid (CSF) tumor markers, ßHCG >200mlU/ml and/or positive alpha-fetoprotein were treated with neoadjuvant chemotherapy with carboplatin, cyclophosphamide and etoposide followed by ventricular radiotherapy (RTV) of 18Gy with boost (32Gy) to the primary site. Metastatic patients underwent craniospinal irradiation (CSI) and "slow responders" to the four initial cycles of CT, to autologous stem cell transplantation (ASCT) followed by CSI. Results: Mean age, 13.1 years. Thirteen males. Primary sites: pineal (n=12), suprasellar (n=2) and bifocal (n=1). Four patients were metastatic at diagnosis. Eight patients had CSF and/or serum alpha-fetoprotein levels > 1,000ng/ml. Tumor responses after chemotherapy demonstrated complete in six cases and partial in seven, with "second-look" surgery being performed in five cases, and two patients presenting viable lesions being referred to ASCT. The main toxicity observed was hematological grades 3/4. Two patients with metastatic disease, one with Down Syndrome and AFP > 1,000ng/ml and the other with choriocarcinoma and pulmonary metastases, developed progressive disease resulting in death, as well as two other patients without evidence of disease, due to endocrinological disorders. Event-free and overall survival at 2 and 5 years were 80% and 72.7%, respectively, with a mean follow-up of 48 months (range, 7-107). Conclusions: Despite the small number of patients, in our series, treatment with six cycles of chemotherapy and RTV with focal boost for localized disease (n=11) and ACST for identified slow responders (n=2) seem to be effective strategies contributing to the overall effort to improve outcomes of this group of patients.

Outcome of Children and Adolescents With Primary Intracranial Germinoma Treated With Chemotherapy and Reduced Dose-Field Irradiation: A Prospective Brazilian Experience.

PURPOSE: This prospective Brazilian single-arm trial was conducted to determine response to chemotherapy and survival after response-based radiotherapy in children with intracranial germinomas, in the setting of a multi-institutional study in a middle-income country (MIC) with significant disparity of subspecialty care. PATIENTS AND METHODS: Since 2013, 58 patients with histologic and/or serum and CSF tumor marker evaluations of primary intracranial germ cell tumors were diagnosed; 43 were germinoma with HCGß levels ≤200 mIU/mL and five between 100 and 200 mIU/mL. The treatment plan consisted of four cycles of carboplatin and etoposide followed by 18 Gy whole-ventricular field irradiation (WVFI) and primary site(s) boost up to 30 Gy; 24 Gy craniospinal was prescribed for disseminated disease. RESULTS: Mean age 13.2 years (range, 4.7-25.5 years); 29 were males. Diagnosis was made by tumor markers (n = 6), surgery (n = 25), or both (n = 10). Two bifocal cases with negative tumor markers were treated as germinoma. Primary tumor location was pineal (n = 18), suprasellar (n = 14), bifocal (n = 10), and basal ganglia/thalamus (n = 1). Fourteen had ventricular/spinal spread documented by imaging studies. Second-look surgery occurred in three patients after chemotherapy. Thirty-five patients achieved complete responses after chemotherapy, and eight showed residual teratoma/scar. Toxicity was mostly grade 3/4 neutropenia/thrombocytopenia during chemotherapy. At a median follow-up of 44.5 months, overall and event-free survivals were 100%. CONCLUSION: The treatment is tolerable, and WVFI dose reduction to 18 Gy preserves efficacy; we have demonstrated the feasibility of successfully conducting a prospective multicenter trial in a large MIC despite resource disparity.

Diverse mutational spectrum in the 13q14 chromosomal region in a Brazilian cohort of retinoblastoma.

Retinoblastoma is a rare childhood tumor caused by the inactivation of both copies of the RB1 gene. Early diagnosis and identification of heritable RB1 mutation carriers can improve the disease outcome and management via genetic counseling. We used the Multiplex Ligation-dependent Probe Amplification (MLPA) method to analyze the RB1 gene and flanking regions in blood samples from 159 retinoblastoma patients previously negative for RB1 point mutations via Sanger sequencing. We detected a wide spectrum of germline chromosomal alterations, ranging from partial loss or duplication of RB1 to large deletions spanning RB1 and adjacent genes. Mutations were validated via karyotyping, fluorescent in situ hybridization (FISH), SNP-arrays (Single Nucleotide Polymorphism-arrays) and/or quantitative relative real-time PCR. Patients with leukocoria as a presenting symptom showed reduced death rate (p = 0.013) and this sign occurred more frequently among carriers of two breakpoints within RB1 (p = 0.05). All unilateral cases presented both breakpoints outside of RB1 (p = 0.0075). Patients with one breakpoint within RB1 were diagnosed at earlier ages (p = 0.017). Our findings characterize the mutational spectrum of a Brazilian cohort of retinoblastoma patients and point to a possible relationship between the mutation breakpoint location and tumor outcome, contributing to a better prospect of the genotype/phenotype correlation and adding to the wide diversity of germline mutations involving RB1 and adjacent regions in retinoblastoma.

An international study evaluating the epidemiology of intracranial germ cell tumors in the native versus immigrant Japanese populations: the need for an international registry.

BACKGROUND: Pediatric intra-cranial germ cell tumors (iGCTs) occur at an incidence of 0.6-1.2 cases/million/year in Western countries. The incidence is reported up to 5 times higher in Japan. It is unknown whether this increased incidence is due to genetic predisposition or environment. METHODS: The incidence of iGCTs in children ages 0-19 years was evaluated from December 1st, 1996-December 1st, 2016 in stable Japanese immigrant populations living abroad and compared to current native Japanese registry data. The incidence of medullobblastoma was used as a control to account for assumptions in the data. Sites were identified based on historical and population data of known large scale emigration from Japan during a period of industrialization from 1868-1912 which resulted in large, stable Japanese immigrant populations abroad. These three representative sites included Lima, Peru, San Paolo, Brazil, and Vancouver, Canada. Data was collected from registry and hospital-based resources within each region. RESULTS: A review of the Brain Tumor Registry of Japan from 1984-2004 revealed an incidence of 2.5 cases/million/year, lower than previously reported, and a lower incidence of medulloblastoma at 1.2 cases/million/year. Data from Vancouver, Canada, Lima, Peru, and San Paolo, Brazil included a total population of 731,174 Japanese persons. The ratio of all medulloblastoma to iGCT cases in Japan was identified as 1:2 while the ratio was 2:1, 6.5:1, and 5:1, respectively, in the other three locations. The data suggests increased incidence in native Japan may not translate to higher incidence in immigrant Japanese populations abroad and a clear genetic component was not found in our data set. CONCLUSIONS: A more precise and comprehensive study is needed to determine the cause of this difference in incidence. This study also emphasizes the importance of national and state registries and is a call to collaborate on state and country level epidemiology studies.

MicroRNAs and exosomes: promising new biomarkers in acute myeloid leukemias?

Despite advances in understanding of carcinogenesis and of treatment of acute myeloid leukemia, this neoplasm still has a lethality of at least 30%. The search for biomarkers that can predict the response to treatment in the early stages of the disease is still necessary. In recent years, a new form of cellular communication between tumor and non-neoplastic cells has been discovered: the exchange of information through extracellular vesicles. These are small vesicles released by membrane-coated cells that carry proteins, lipids, messenger RNAs, microRNA and DNA, which can be internalized and promote biological changes in target cells. Exosomes are qualified as a type of extracellular vesicle and, in tumors, carry immunoinhibitory signals that promote the escape of immune control. Recent studies have showed their involvement in communication with the cells of the tumor microenvironment and with chemoresistance in several tumors. To date, there is no information about immunoregulatory microRNAs transported by exosomes and their correlation with clinical evolution during chemotherapy for acute myeloid leukemia. Knowledge about immunomodulatory microRNAs obtained by leukemic cells and transported by exosomes can direct us towards the design of new diagnostic and treatment tools in this type of leukemia.

MicroRNAs and exosomes: promising new biomarkers in acute myeloid leukemias?

ABSTRACT Despite advances in understanding of carcinogenesis and of treatment of acute myeloid leukemia, this neoplasm still has a lethality of at least 30%. The search for biomarkers that can predict the response to treatment in the early stages of the disease is still necessary. In recent years, a new form of cellular communication between tumor and non-neoplastic cells has been discovered: the exchange of information through extracellular vesicles. These are small vesicles released by membrane-coated cells that carry proteins, lipids, messenger RNAs, microRNA and DNA, which can be internalized and promote biological changes in target cells. Exosomes are qualified as a type of extracellular vesicle and, in tumors, carry immunoinhibitory signals that promote the escape of immune control. Recent studies have showed their involvement in communication with the cells of the tumor microenvironment and with chemoresistance in several tumors. To date, there is no information about immunoregulatory microRNAs transported by exosomes and their correlation with clinical evolution during chemotherapy for acute myeloid leukemia. Knowledge about immunomodulatory microRNAs obtained by leukemic cells and transported by exosomes can direct us towards the design of new diagnostic and treatment tools in this type of leukemia.

Low-grade glioma: A rare second tumor in retinoblastoma survivors.

Retinoblastoma survivors with a germline RB1 mutation are at elevated risk for secondary (nonocular) malignancy, but their risk for low-grade glioma (LGG) is unknown. We performed a retrospective review of the Memorial Sloan Kettering Cancer Center and the NCI databases that revealed that three of the 837 5-year survivors of hereditary retinoblastoma were diagnosed with an LGG and a fourth patient (but unilateral and without a germline mutation) was identified at another center. Retinoblastoma survivors may be at increased risk for LGG.

Caesarean sections, prenatal and postnatal conditions and childhood acute lymphoblastic leukaemia: A case-control study in the State of São Paulo, Brazil.

INTRODUCTION: Brazil has high rates of caesarean sections, which has been suggested as a risk factor for acute lymphoblastic leukaemia (ALL). In addition, some pre- and postnatal conditions have been identified as relevant in the etiology of ALL. OBJECTIVES: Investigate the association of caesarean sections, pre- and postnatal conditions with childhood ALL in the State of São Paulo. METHODS: Population-based case-control study including children that are below10 years old. Information on study variables was obtained through face to face interviews, through a questionnaire, and the State of São Paulo Declarations of Live Births database. The conditional and unconditional logistic regression approaches were used to calculate the odds ratio (OR) of the associations between caesarean sections, pre- and postnatal conditions with ALL, and 95 % confidence intervals (95 % CI). RESULTS: We observed a weak and non-statistically significant risk for ALL among children exposed to caesarean sections (unconditional logistic regression OR 1.08; 95 % CI 0.70-1.66; conditional logistic regression OR 1.21; 95 % CI 0.72-2.02), but among children under 3 years old and born through a caesarean sections, the risk of ALL was greater (unconditional logistic regression OR 1.70; 95 % CI 0.69-4.21). A negative association for ALL was observed among children with mothers who reported 12 years of schooling or more (unconditional logistic regression OR 0.34; 95 % CI 0.16-0.69). CONCLUSIONS: We found a tenuous suggestive association between caesarean sections and childhood ALL. The mother's high level of education showed an inverse association with ALL.

Prevention of cisplatin-induced ototoxicity in children and adolescents with cancer: a clinical practice guideline.

Despite ototoxicity being a prevalent consequence of cisplatin chemotherapy, little guidance exists on interventions to prevent this permanent and progressive adverse event. To develop a clinical practice guideline for the prevention of cisplatin-induced ototoxicity in children and adolescents with cancer, we convened an international, multidisciplinary panel of experts and patient advocates to update a systematic review of randomised trials for the prevention of cisplatin-induced ototoxicity. The systematic review identified 27 eligible adult and paediatric trials that evaluated amifostine, sodium diethyldithiocarbamate or disulfiram, systemic sodium thiosulfate, intratympanic therapies, and cisplatin infusion duration. Regarding systemic sodium thiosulfate, the panel made a strong recommendation for administration in non-metastatic hepatoblastoma, a weak recommendation for administration in other non-metastatic cancers, and a weak recommendation against its routine use in metastatic cancers. Amifostine, sodium diethyldithiocarbamate, and intratympanic therapy should not be routinely used. Cisplatin infusion duration should not be altered as a means to reduce ototoxicity. Further research to determine the safety of sodium thiosulfate in patients with metastatic cancer is encouraged.

Metronomic Chemotherapy for Children in Low- and Middle-Income Countries: Survey of Current Practices and Opinions of Pediatric Oncologists.

PURPOSE: Low- and middle-income countries (LMICs) experience the burden of 80% of new childhood cancer cases worldwide, with cure rates as low as 10% in some countries. Metronomics combines frequent administrations of low-dose chemotherapy with drug repurposing, which consists of using already-approved drugs for new medical applications. With wide availability, limited costs, and little infrastructure needs, metronomics can be part of constraint-adapted regimens in these resource-limited settings-with the understanding that metronomics shall not be a substitute for standard treatments when available and doable. Our study aims to describe the experience, practices, opinions, and needs in metronomics of physicians working in LMICs. METHODS: An online questionnaire was sent to more than 1,200 physicians in pediatric oncology networks in LMICs. Items included the type of center, physician's demographics, experience in pediatric oncology, and experience with current knowledge of metronomics. Opinions and perspectives were explored using multiple-answer and open questions. RESULTS: Of physicians, 17% responded. Of respondents, 54.9% declared that they had already used a metronomic regimen. The most frequently cited repositioned drugs were celecoxib (44%) followed by propranolol and valproic acid (17%). Respondents highlighted the advantages of outpatient use (20%) and expected low toxicity (24%). In considering the drawbacks of metronomics, 47% of responses highlighted the lack of scientific evidence or guidelines, 33% the availability or affordability of drugs, and 18% the problem of acceptance or compliance. Of physicians, 79% believed that use of metronomics will spread in LMICs in the near future and 98% of them were willing to participate in international metronomic protocols or registries. CONCLUSION: Metronomics is already used in LMICs and is a potential answer to unmet needs in pediatric oncology. There is room for improvement in the availability of drugs and a necessity to develop collaborative protocols and research to generate level A evidence.

Frequency of EBV LMP-1 Promoter and Coding Variations in Burkitt Lymphoma Samples in Africa and South America and Peripheral Blood in Uganda.

Epstein-Barr virus (EBV) is linked to several cancers, including endemic Burkitt lymphoma (eBL), but causal variants are unknown. We recently reported novel sequence variants in the LMP-1 gene and promoter in EBV genomes sequenced from 13 of 14 BL biopsies. Alignments of the novel sequence variants for 114 published EBV genomes, including 27 from BL cases, revealed four LMP-1 variant patterns, designated A to D. Pattern A variant was found in 48% of BL EBV genomes. Here, we used PCR-Sanger sequencing to evaluate 50 additional BL biopsies from Ghana, Brazil, and Argentina, and peripheral blood samples from 113 eBL cases and 115 controls in Uganda. Pattern A was found in 60.9% of 64 BL biopsies evaluated. Compared to PCR-negative subjects in Uganda, detection of Pattern A in peripheral blood was associated with eBL case status (odds ratio [OR] 31.7, 95% confidence interval: 6.8⁻149), controlling for relevant confounders. Variant Pattern A and Pattern D were associated with eBL case status, but with lower ORs (9.7 and 13.6, respectively). Our results support the hypothesis that EBV LMP-1 Pattern A may be associated with eBL, but it is not the sole associated variant. Further research is needed to replicate and elucidate our findings.

Highlights from the 1st Latin American meeting on metronomic chemotherapy and drug repositioning in oncology, 27-28 May, 2016, Rosario, Argentina.

Following previous metronomic meetings in Marseille (2011), Milano (2014), and Mumbai (2016), the first Latin American metronomic meeting was held in the School of Medical Sciences, National University of Rosario, Rosario, Argentina on 27 and 28 of May, 2016. For the first time, clinicians and researchers with experience in the field of metronomics, coming from different countries in Latin America, had the opportunity of presenting and discussing their work. The talks were organised in three main sessions related to experience in the pre-clinical, and clinical (paediatric and adult) areas. The different presentations demonstrated that the fields of metronomic chemotherapy and repurposing drugs in oncology, known as metronomics, constitute a branch of cancer therapy in permanent evolution, which have strong groups working in Latin America, both in the preclinical and the clinical settings including large, adequately designed randomised studies. It was shown that metronomics offers treatments, which, whether they are combined or not with the standard therapeutic approaches, are not only effective but also minimally toxic, with the consequent improvement of the patient's quality of life, and inexpensive, a feature very important in low resource clinical settings. The potential use of metronomic chemotherapy was proposed as a cost/effective treatment in low-/middle-income countries, for adjuvant therapy in selected tumours. The fundamental role of the governmental agencies and non-governmental alliances, as the Metronomic Global Health Initiative, in supporting this research with public interest was underlined.

Epstein-Barr virus from Burkitt Lymphoma biopsies from Africa and South America share novel LMP-1 promoter and gene variations.

Epstein Barr virus (EBV) sequence variation is thought to contribute to Burkitt lymphoma (BL), but lack of data from primary BL tumors hampers efforts to test this hypothesis. We directly sequenced EBV from 12 BL biopsies from Ghana, Brazil, and Argentina, aligned the obtained reads to the wild-type (WT) EBV reference sequence, and compared them with 100 published EBV genomes from normal and diseased people from around the world. The 12 BL EBVs were Type 1. Eleven clustered close to each other and to EBV from Raji BL cell line, but away from 12 EBVs reported from other BL-derived cell lines and away from EBV from NPC and healthy people from Asia. We discovered 23 shared novel nucleotide-base changes in the latent membrane protein (LMP)-1 promoter and gene (associated with 9 novel amino acid changes in the LMP-1 protein) of the 11 BL EBVs. Alignment of this region for the 112 EBV genomes revealed four distinct patterns, tentatively termed patterns A to D. The distribution of BL EBVs was 48%, 8%, 24% and 20% for patterns A to D, respectively; the NPC EBV's were Pattern B, and EBV-WT was pattern D. Further work is needed to investigate the association between EBV LMP-1 patterns with BL.

Cancer in adolescents and young adults in countries with limited resources.

Cancer in adolescents and young adults (AYA) represents a higher fraction of all cancer in countries that are still undergoing a demographic transition. Such countries tend to have much younger populations, and therefore unless they have a particularly low incidence of cancer in this age group, will have a higher burden of cancer (absolute number of cases with cancer) in AYA. Cancers in AYA are comprised of the tail end of the incidence curve of cancers that have their peak incidence, or occur almost exclusively in childhood, the beginning of the incidence curve of cancers that primarily affect the elderly, and a third set of cancers that have their peak incidence (or are at least common) in the AYA age group (e.g., testicular cancer, sarcomas, melanoma, thyroid cancer). Many, but not all, of these cancers require radiation or cancer surgery, but the poorest countries do not have a sufficient number of radiation therapy units and surgical oncologists, or indeed medical and pediatric oncologists, to deal with the burden of cancer they face. The AYA age group is particularly important, both with regard to their contribution to the economy now and in the future (the majority are in the "working" age-group defined as 15-64 years), as well as their important role in caring for their families. Moreover, some of these cancers are eminently curable with chemotherapy alone, and more could be cured by simply improving the efficiency of existing health services and providing education and training to both the public as well as oncologists and other specialists required for the care of AYA (although such individuals will not necessarily be exclusively concerned with this age group). Of particular importance is the detection and diagnosis of cancer patients at the earliest possible time in the course of their disease. Avoiding delays in initiating therapy, which are partly due to the poverty and lack of education of the public as well as to a failure on the part of primary health care providers to recognize the possibility of cancer, would lead not only to improved survival and less toxicity, but is likely to reduce the need for radiation as well as the cost of treatment. There are few good quality clinical trials that take place in the LMIC (in relationship to the extent of the existing cancer burden), and research training should be an integral component of capacity building. Research on the efficacy and toxicity of standardized treatment approaches that are either based on principles established in the HIC, or adapted from treatment protocols used in the HIC, would be a good place to begin, but health policy and multisectoral collaboration are essential if improved survival rates are to be achieved. Decisions will also need to be made regarding the treatment of diseases in which radiation or cancer surgery are important elements, when one or both of the latter are unavailable. Late effects are important in this young population in HIC, and protocol adaptations or design in LMIC should take into consideration the significant fraction of cured patients with late effects who were treated in HIC in an era where improving response and survival rates was the paramount consideration-the situation that applies today in less developed countries. Special adolescent units which better deal with psychological issues of young cancer patients are rare in LMIC and the psychosocial issues faced by adolescents are much less studied. Although survival is the first consideration, attention to psychosocial and financial issues may reduce existing delays in initiating therapy and also the fraction of patients that abandon therapy.

The adolescent and young adult with cancer: state of the art--brain tumor.

The management of adolescents and young adults with brain tumors, which consist of many different histologic subtypes, continues to be a challenge. Better outcome with a decrease of the side effects of the disease and therapy and improvement of quality of life has been demonstrated in recent decades for some tumors. Significant differences in survival and cure are also observed between adult and pediatric tumors of the same histologic grade. Genetic, developmental, and environmental factors likely influence the type of tumor and response observed, even though no clear pathologic features differentiate these lesions among children, adolescents, and adults. Similarly, treatment strategies are not identical among these populations; most patients receive surgery, followed by radiation therapy and multiagent chemotherapy. Advances in understanding the biology underlying the distribution of tumors in adolescents and young adults may influence the development of prospective trials. A more individualized view of these tumors will likely influence stratification of patients in future studies as well as selection for targeted agents. Accordingly, outcomes may improve and long-term morbidities may decrease.

Paediatric cancer in low-income and middle-income countries.

Patterns of cancer incidence across the world have undergone substantial changes as a result of industrialisation and economic development. However, the economies of most countries remain at an early or intermediate stage of development-these stages are characterised by poverty, too few health-care providers, weak health systems, and poor access to education, modern technology, and health care because of scattered rural populations. Low-income and middle-income countries also have younger populations and therefore a larger proportion of children with cancer than high-income countries. Most of these children die from the disease. Chronic infections, which remain the most common causes of disease-related death in all except high-income countries, can also be major risk factors for childhood cancer in poorer regions. We discuss childhood cancer in relation to global development and propose strategies that could result in improved survival. Education of the public, more and better-trained health professionals, strengthened cancer services, locally relevant research, regional hospital networks, international collaboration, and health insurance are all essential components of an enhanced model of care.

Fifteen Years' Experience of the Brazilian Osteosarcoma Treatment Group (BOTG): A Contribution from an Emerging Country.

PURPOSE: Little information is available regarding the tumor features, prognostic factors, and treatment results in children and adolescents and young adults (AYAs) with osteosarcoma diagnosed in developing countries. We reviewed the results of three observational cohorts of osteosarcoma patients treated in an emerging country. METHODS: A total of 604 patients below the age of 30 years with high-grade osteosarcoma were prospectively enrolled in the Brazilian Osteosarcoma Treatment Group (BOTG) studies III, IV, and V. Gender, age, time from onset of symptoms to diagnosis, primary tumor site, presence or absence of metastases at diagnosis, tumor size, type of surgery (limb-sparing or amputation), treatment protocol, and histological response were correlated with survival. RESULTS: The estimated 5-year overall survival and event-free survival (EFS) rates for the 553 eligible patients were 49% and 39% respectively; of the 390 non-metastatic patients included in the total, overall- and event-free survival were 59% and 48% respectively. Metastases at diagnosis, primary tumor site, type of surgery, and histological response were significant predictors of overall survival and EFS in univariate and multivariate analysis, whereas tumor size and treatment protocol lost prognostic significance in multivariate analysis. CONCLUSION: We report on the outcome of three consecutive studies for the treatment of osteosarcoma carried out in Brazil over 15 years. Although the survival rates presented are below those reported in current literature, it represents the result of a favorable experience gathered from the national collaborative work.

Preserving vision in retinoblastoma through early detection and intervention.

The most frequent neoplasm of the eye in children is retinoblastoma. It is a rare disease with an average incidence of 1 in 14,000 to 18,000 live births. The incidence is greater in developing countries. Early detection may allow widespread use of eye-sparing treatments, minimizing the morbidity of this disease. Although leukocoria is usually the first sign that parents notice especially when a flash photograph is taken, the diagnosis is not performed since this presentation is not known by health care providers and the public. Improving public awareness and knowledge of the early signs may lead to early diagnosis, which can save more eyes and lives. Advances in both the basic science and clinical applications of new therapies continue to emerge for this rare cancer. We expect that all conservative treatments will be available worldwide and consequently more children will be cured and maintain the vision.

Exposure to magnetic fields and childhood acute lymphocytic leukemia in São Paulo, Brazil.

BACKGROUND: Epidemiological studies have identified increased risks of leukemia in children living near power lines and exposed to relatively high levels of magnetic fields. Results have been remarkably consistent, but there is still no explanation for this increase. In this study we evaluated the effect of 60 Hz magnetic fields on acute lymphocytic leukemia (ALL) in the State of São Paulo, Brazil. METHODS: This case-control study included ALL cases (n=162) recruited from eight hospitals between January 2003 and February 2009. Controls (n=565) matched on gender, age, and city of birth were selected from the São Paulo Birth Registry. Exposure to extremely low frequency magnetic fields (ELF MF) was based on measurements inside home and distance to power lines. RESULTS: For 24h measurements in children rooms, levels of ELF MF equal to or greater than 0.3microtesla (µT), compared to children exposed to levels below 0.1 µT showed no increased risk of ALL (odds ratio [OR] 1.09; 95% confidence interval [95% CI] 0.33-3.61). When only nighttime measurements were considered, a risk (OR 1.52; 95% CI 0.46-5.01) was observed. Children living within 200 m of power lines presented an increased risk of ALL (OR 1.67; 95% CI 0.49-5.75), compared to children living at 600 m or more of power lines. For those living within 50 m of power lines the OR was 3.57 (95% CI 0.41-31.44). CONCLUSIONS: Even though our results are consistent with the small risks reported in other studies on ELF MF and leukemia in children, overall our results do not provide support for an association between magnetic fields and childhood leukemia, but small numbers and likely biases weaken the strength of this conclusion.