International Society of Paediatric Oncology (SIOP) Global Mapping Programme: Latin American Society of Pediatric Oncology (SLAOP) country-level report

BACKGROUND

Latin American countries are improving childhood cancer care, showing strong commitment to implement the Global Initiative for Childhood Cancer, but there are scant publications of the situation at a continental level.

METHODS

As part of the International Society of Paediatric Oncology Global Mapping project, delegates of each country participating in the Latin American Society of Pediatric Oncology (SLAOP) and chairs of national pediatric oncology societies and cooperative groups were invited to provide information regarding availability of national pediatric cancer control programs (NPCCP), pediatric oncology laws, pediatric oncology tumor registries, and training programs and support to diagnosis and treatment.

RESULTS

Nineteen of the 20 countries participating in SLAOP responded. National delegates reported nine countries with NPCCP and four of them were launched in the past 5 years. National pediatric tumor registries are available in eight countries, and three provided published survival results. Fellowship programs for training pediatric oncologists are available in 12 countries. National delegates reported that eight countries provide support to most essential diagnosis and treatments and 11 provide partial or minimal support that is supplemented by civil society organizations. Seven countries have a pediatric oncology law. There are three international cooperative groups and four national societies for pediatric oncology.

CONCLUSION

Despite many challenges, there were dramatic advances in survivorship, access to treatment, and availability of NPCCP in Latin America. Countries with highest social development scores in general provide more complete support and are more likely to have NPCCP, training programs, and reported survival results.

Induction therapy for acute lymphoblastic leukemia: incidence and risk factors for bloodstream infections

Among the treatment-related acute toxic effects, risks for bloodstream infections (BSIs) are associated with several variables. The authors carried out a retrospective cohort study with 259 children and adolescents with ALL, treated with the GBTLI-LLA 2009 protocol, in order to assess the incidence of BSIs in the induction phase; to determine the risk factors for these BSIs; and to identify the related microorganisms and sensitivity profile of the microorganisms related to these infections. BSIs were documented in 19.3% of patients. The isolated microorganisms were 39 Gram-negative bacteria, 21 Gram-positive bacteria, and four fungi. There was a statistically significant risk of BSI between the variables: protocol for T-line-derived leukemia (Derived T Protocol) (p = 0.020), oral manifestations (p = 0.015), central venous catheter (p = 0.008), and bladder catheter (p = 0.004). BSI is a frequent event in ALL patients during the induction phase. The identification of these factors can allow the elaboration and improvement of strategies for the intensification of supportive care, prevention, and rapid treatment of infections.

Adherence to dental treatment reduces oral complications related to cancer treatment in pediatric and adolescent patients

PURPOSE

To analyze the association between adherence to dental treatment and (1) oral complications and (2) clinical and sociodemographic aspects of pediatric and adolescent patients with cancer.

METHODS

A retrospective cohort study with a sample of 147 children and adolescents who underwent cancer treatment of solid tumors or lymphomas was carried out. The patients were divided into three groups according to previously established criteria. Sociodemographic aspects and oncological, dental, and oral complications were analyzed.

RESULTS

The mean age of patients was 6.7 ± 6.09 years; 57.1% were males and 42.9% were females. Of the 147 patients, 37.41% had full adherence, 33.3% had partial adherence, and 29.3% had non-adherence to the proposed dental treatment. A statistically significant association between oral complications and adherence to dental treatment (p = 0.006) could be observed. The presence of caries lesions at the initial oral examination presented a statistically significant association with adherence to dental treatment (p = 0.004). Children with caries lesions at the initial dental examination had an 88% higher risk of developing oral complications compared with those without caries (RR = 1.88, 95% CI 1.01-3.49). After adjustments for age and the presence of caries lesions at the initial examination, adherence to dental treatment remained the only independent risk factor for oral complications (adjusted RR = 2.56, 95% CI 1.17-5.57).

CONCLUSIONS

This study has demonstrated that non-adherence to dental treatment was associated with higher incidence of oral complications and it is a risk factor for these complications. The presence of caries lesions at the initial oral examination was associated with non-adherence to dental treatment.

Factors affecting diagnosis of primary pediatric central nervous system neoplasias in a developing country

PURPOSE

Understand the variables that could interfere with diagnosis and prompt treatment in CNS childhood cancer in Brazil, a developing country with continental dimensions.

METHODS

From 2005 to 2010, we retrospectively evaluated factors, which could represent a negative influence on the time period elapsing from the onset of symptoms until the diagnosis of the central nervous system (CNS) neoplasia in children and adolescents attended in our service.

RESULTS

Two hundred seventeen records were analyzed retrospectively. Factors of the households were evaluated, and this data was related to the time period elapsing from presentation of the first symptoms until the diagnosis of CNS neoplasia. The average time elapsed from the onset of the symptoms until seeking medical assistance was 96 days, and from medical assistance to patient referral to a reference service was 33 days. The symptoms which most contributed to a shorter delay in diagnosis were changes in gait and paresis, mother's occupation, father's education level, patient gender, and living in the state of São Paulo. Besides that, variables such as male gender, mother's education level, and lower patient age were associated with an early diagnosis time.

CONCLUSION

There is great difficulty in performing early diagnosis of CNS tumors, partly due to parent's inability to recognize signs and symptoms, and in part due to an educational deficit among healthcare professionals. Identification of measures that can minimize these causes of delay is fundamental to increasing the chance of cure and survival of these patients.

Reduced hydroxymethylation characterizes medulloblastoma while TET and IDH genes are differentially expressed within molecular subgroups

INTRODUCTION

Medulloblastoma (MB) is an embryonal tumour that originates from genetic deregulation of cerebellar developmental pathways and is classified into 4 molecular subgroups: SHH, WNT, group 3, and group 4. Hydroxymethylation levels progressively increases during cerebellum development suggesting a possibility of deregulation in MB pathogenesis. The aim of this study was to investigate global hydroxymethylation levels and changes in TET and IDH gene expression in MB samples compared to control cerebellum samples.

METHODS

The methods utilized were qRT-PCR for gene expression, dot-blot and immunohistochemistry for global hydroxymethylation levels and sequencing for the investigation of IDH mutations.

RESULTS

Our results show that global hydroxymethylation level was decreased in MB, and low 5hmC level was associated with the presence of metastasis. TET1 expression levels were decreased in the WNT subgroup, while TET3 expression levels were decreased in the SHH subgroup. Reduced TET3 expression levels were associated with the presence of events such as relapse and death. Higher expression of IDH1 was observed in MB group 3 samples, whereas no mutations were detected in exon 4 of IDH1 and IDH2.

CONCLUSION

These findings suggest that reduction of global hydroxymethylation levels, an epigenetic event, may be important for MB development and/or maintenance, representing a possible target in this tumour and indicating a possible interaction of TET and IDH genes with the developmental pathways specifically activated in the MB subgroups. These genes could be specific targets and markers for each subgroup.

The DNA methyltransferase inhibitor zebularine exerts antitumor effects and reveals BATF2 as a poor prognostic marker for childhood medulloblastoma

Medulloblastoma (MB) is the most common solid tumor among pediatric patients and corresponds to 20 % of all pediatric intracranial tumors in this age group. Its treatment currently involves significant side effects. Epigenetic changes such as DNA methylation may contribute to its development and progression. DNA methyltransferase (DNMT) inhibitors have shown promising anticancer effects. The agent Zebularine acts as an inhibitor of DNA methylation and shows low toxicity and high efficacy, being a promising adjuvant agent for anti-cancer chemotherapy. Several studies have reported its effects on different types of tumors; however, there are no studies reporting its effects on MB. We analyzed its potential anticancer effects in four pediatric MB cell lines. The treatment inhibited proliferation and clonogenicity, increased the apoptosis rate and the number of cells in the S phase (p < 0.05), as well as the expression of p53, p21, and Bax, and decreased cyclin A, Survivin and Bcl-2 proteins. In addition, the combination of zebularine with the chemotherapeutic agents vincristine and cisplatin resulted in synergism and antagonism, respectively. Zebularine also modulated the activation of the SHH pathway, reducing SMO and GLI1 levels and one of its targets, PTCH1, without changing SUFU levels. A microarray analysis revealed different pathways modulated by the drug, including the Toll-Like Receptor pathway and high levels of the BATF2 gene. The low expression of this gene was associated with a worse prognosis in MB. Taken together, these data suggest that Zebularine may be a potential drug for further in vivo studies of MB treatment.

Lowered Cisplatin Dose and No Bleomycin in the Treatment of Pediatric Germ Cell Tumors: Results of the GCT-99 Protocol From the Brazilian Germ Cell Pediatric Oncology Cooperative Group

PURPOSE

We describe the results of a risk-adapted, response-based therapeutic approach from the Brazilian GCT-99 study on germ cell tumors.

PATIENTS AND METHODS

From May 1999 to October 2009, 579 participants were enrolled in the Brazilian GCT-99 study. Treatment, defined as specific chemotherapy regimen and number of cycles, was allocated by means of risk-group assignment at diagnosis with consideration for stage and primary tumor site. Patients at low risk received no chemotherapy. Patients at intermediate risk (IR) with a good response (GR) received four cycles of platinum and etoposide (PE), for total doses of platinum 420 mg/m(2) and etoposide 2,040 mg/m(2). Patients at IR with a partial response (PR) received three cycles of PE plus three cycles of ifosfamide, vinblastine, and bleomycin. Patients at high risk (HR) with a GR received four cycles of PE and ifosfamide (PEI) at total doses of platinum 420 mg/m(2), etoposide 1,200 mg/m(2), and ifosfamide 30 g/m(2). Patients at HR with a PR received six cycles of PEI.

RESULTS

The risk-group distribution was 213 LR, 138 IR, and 129 HR for 480 evaluable patients. Overall survival (OS) and event-free survival (EFS) rates at 10 years were, respectively, 90% and 88.6% in the IR-GR group (n = 126) and 74.1% and 74.1% in the IR-PR group (n = 12). Ten-year rates for the HR-GR group (n = 86) were an OS of 66.8% and an EFS of 62.5%. The HR-PR group (n = 43) had an OS of 74.8% and an EFS of 73.4%. In univariable and multivariable analysis, increased serum lactate dehydrogenase level and histology for a metastatic immature teratoma were prognostic of a worsened outcome.

CONCLUSION

Reduction of therapy to two drugs did not compromise survival outcomes for patients in the IR-GR group, and escalation of therapy with PEI did not significantly improve OS and EFS in patients at HR.

Mobilization and collection of CD34(+) cells for autologous transplantation of peripheral blood hematopoietic progenitor cells in children: analysis of two different granulocyte-colony stimulating factor doses

INTRODUCTION

The use of peripheral hematopoietic progenitor cells (HPCs) is the cell choice in autologous transplantation. The classic dose of granulocyte-colony stimulating factor (G-CSF) for mobilization is a single daily dose of 10μg/kg of patient body weight. There is a theory that higher doses of granulocyte-colony stimulating factor applied twice daily could increase the number of CD34(+) cells collected in fewer leukapheresis procedures.

OBJECTIVE

The aim of this study was to compare a fractionated dose of 15μg G-CSF/kg of body weight and the conventional dose of granulocyte-colony stimulating factor in respect to the number of leukapheresis procedures required to achieve a minimum collection of 3×10(6) CD34(+) cells/kg body weight.

METHODS

Patients were divided into two groups: Group 10 - patients who received a single daily dose of 10μg G-CSF/kg body weight and Group 15 - patients who received a fractioned dose of 15μg G-CSF/kg body weight daily. The leukapheresis procedure was carried out in an automated cell separator. The autologous transplantation was carried out when a minimum number of 3×10(6) CD34(+) cells/kg body weight was achieved.

RESULTS

Group 10 comprised 39 patients and Group 15 comprised 26 patients. A total of 146 apheresis procedures were performed: 110 (75.3%) for Group 10 and 36 (24.7%) for Group 15. For Group 10, a median of three (range: 1-7) leukapheresis procedures and a mean of 8.89×10(6) CD34(+) cells/kg body weight (±9.59) were collected whereas for Group 15 the corresponding values were one (range: 1-3) and 5.29×10(6) cells/kg body weight (±4.95). A statistically significant difference was found in relation to the number of apheresis procedures (p-value <0.0001).

CONCLUSIONS

To collect a minimum target of 3×10(6) CD34(+) cells/kg body weight, the administration of a fractionated dose of 15μg G-CSF/kg body weight significantly decreased the number of leukapheresis procedures performed.

Downregulation of 14q32 microRNAs in Primary Human Desmoplastic Medulloblastoma

Medulloblastoma (MB) is one of the most common pediatric cancers, likely originating from abnormal development of cerebellar progenitor neurons. MicroRNA (miRNA) has been shown to play an important role in the development of the central nervous system. Microarray analysis was used to investigate miRNA expression in desmoplastic MB from patients diagnosed at a young age (1 or 2 years old). Normal fetal or newborn cerebellum was used as control. A total of 84 differentially expressed miRNAs (64 downregulated and 20 upregulated) were found. Most downregulated miRNAs (32/64) were found to belong to the cluster of miRNAs at the 14q32 locus, suggesting that this miRNA locus is regulated as a module in MB. Possible mechanisms of 14q32 miRNAs downregulation were investigated by the analysis of publicly available gene expression data sets. First, expression of estrogen-related receptor-γ (ESRRG), a reported positive transcriptional regulator of some 14q32 miRNAs, was found downregulated in desmoplastic MB. Second, expression of the parentally imprinted gene MEG3 was lower in MB in comparison to normal cerebellum, suggesting a possible epigenetic silencing of the 14q32 locus. miR-129-5p (11p11.2/7q32.1), miR-206 (6p12.2), and miR-323-3p (14q32.2), were chosen for functional studies in DAOY cells. Overexpression of miR-129-5p using mimics decreased DAOY proliferation. No effect was found with miR-206 or miR-323 mimics.

Retinoblastoma diagnosis: a proposal based on the experience of Centro Infantil Boldrini, Brazil

Advanced disease is a risk factor for eye loss in patients with retinoblastoma (RB). We still record critical rates of enucleation, especially for unilateral RB due to advanced stages of disease at diagnosis. This retrospective study of 223 RB patient records referred to treatment at Centro Infantil Boldrini, Brazil, between 1978 and 2008, showed that 176 patients (79%) presented intraocular tumors while 47 (21%) already had extraocular involvement. At the time of diagnosis, the age of patients was 26.2 months in the group that had enucleated eyes and 13.7 months in the group that preserved both eyes. Under a multiple logistic regression model, familial history (OR = 0.195; p = .01) and age at diagnosis in months (OR = 1.047; p = .04) were significantly correlated with enucleation. Strategies to early detect RB must be changed in order to offer better chances of ocular preservation with visual function. Authors propose a systematic referral of all children to the ophthalmologist for an indirect ophthalmoscopy once a year in the first two years of life, as a measure to be adopted by all pediatricians in daily routine to early detect the tumor.

Association of the highly prevalent TP53 R337H mutation with pediatric choroid plexus carcinoma and osteosarcoma in southeast Brazil

BACKGROUND

The inherited, low-penetrance arginine-to-histidine substitution at codon 337 (R337H) of the tumor protein 53 gene (TP53) is clustered in southeast Brazil (estimated frequency, 0.3%). Although its tumorigenic effect initially appeared to be tissue-specific, recent evidence suggests its association with a broader range of tumors. Therefore, the authors of this report investigated the spectrum of pediatric malignancies associated with the TP53 R337H mutation at a single referral institution in southeast Brazil.

METHODS

Genomic DNA samples from 493 children with malignancies were screened for the R337H mutation. Available tumor samples from carriers were investigated for loss of heterozygosity (LOH) and nuclear p53 accumulation. Clinical data were obtained from medical records.

RESULTS

Sixty-five of 70 patients (93%) with adrenocortical tumors (ACTs), 9 of 13 patients (69%) with choroid plexus carcinoma (CPC), and 3 of 41 patients (7.3%) with osteosarcoma carried the mutation. The proportion of CPC to choroid plexus papilloma (CPP) was much higher than that reported elsewhere. Osteosarcoma in carriers had a significantly poorer outcome (P = .02). The mutation was not identified in patients who had acute lymphoblastic leukemia (ALL) (n = 187), recurrent ALL (n = 49), acute myeloid leukemia (n = 44), lymphoma (n = 30), non-CPC central nervous system tumors (n = 26), Ewing sarcoma (n = 25), or rhabdomyosarcoma (n = 8). Among the tumors that were available for analysis, LOH with retention of the mutant allele was confirmed in 21 of 21 ACTs, in 2 of 2 CPCs, and in 2 of 3 osteosarcomas that were positive for R337H. CPCs and osteosarcomas that were positive for R337H had marked nuclear accumulation of p53.

CONCLUSIONS

The current findings demonstrated compellingly that the TP53 R337H mutation is associated not only with ACT but also with CPC and, to a lesser extent, with osteosarcoma, both of which are core-component tumors of the Li-Fraumeni syndrome.