Epidemiology of childhood cancer. Cancer Treat Rev. 2010;36:277-285. [PMID: 20231056 DOI: 10.1016/j.ctrv.2010.02.003]

Helical tomotherapy in children and adolescents: dosimetric comparisons, opportunities and issues

Helical Tomotherapy (HT) is a highly conformal image-guided radiation technique, introduced into clinical routine in 2006 at the Centro di Riferimento Oncologico Aviano (Italy). With this new technology, intensity-modulated radiotherapy (IMRT) is delivered using a helicoidal method. Here we present our dosimetric experiences using HT in 100 children, adolescents and young adults treated from May 2006 to February 2011. The median age of the patients was 13 years (range 1-24). The most common treated site was the central nervous system (50; of these, 24 were craniospinal irradiations), followed by thorax (22), head and neck (10), abdomen and pelvis (11), and limbs (7). The use of HT was calculated in accordance to the target dose conformation, the target size and shape, the dose to critical organs adjacent to the target, simultaneous treatment of multiple targets, and re-irradiation. HT has demonstrated to improve target volume dose homogeneity and the sparing of critical structures, when compared to 3D Linac-based radiotherapy (RT). In standard cases this technique represented a comparable alternative to IMRT delivered with conventional linear accelerator. In certain cases (e.g., craniospinal and pleural treatments) only HT generated adequate treatment plans with good target volume coverage. However, the gain in target conformality should be balanced with the spread of low-doses to distant areas. This remains an open issue for the potential risk of secondary malignancies (SMNs) and longer follow-up is mandatory.

Maternal and gestational factors and micronucleus frequencies in umbilical blood: the NewGeneris Rhea cohort in Crete

BACKGROUND

The use of cancer-related biomarkers in newborns has been very limited.

OBJECTIVE

We investigated the formation of micronuclei (MN) in full-term and preterm newborns and their mothers from the Rhea cohort (Crete), applying for the first time in cord blood a validated semiautomated analysis system, in both mono- and binucleated T lymphocytes.

METHODS

We assessed MN frequencies in peripheral blood samples from the mothers and in umbilical cord blood samples. We calculated MN in mononucleated (MNMONO) and binucleated (MNBN) T lymphocytes and the cytokinesis block proliferation index (CBPI) in 251 newborns (224 full term) and 223 mothers, including 182 mother-child pairs. Demographic and lifestyle characteristics were collected.

RESULTS

We observed significantly higher MNBN and CBPI levels in mothers than in newborns. In newborns, MNMONO and MNBN were correlated (r = 0.35, p < 0.001), and we found a moderate correlation between MNMONO in mothers and newborns (r = 0.26, p < 0.001). MNMONO frequencies in newborns were positively associated with the mother's body mass index and inversely associated with gestational age and mother's age, but we found no significant predictors of MNBN or CBPI in newborns.

CONCLUSIONS

Although confirmation is needed by a larger study population, the results indicate the importance of taking into account both mono- and binucleated T lymphocytes for biomonitoring of newborns, because the first reflects damage expressed during in vivo cell division and accumulated in utero, and the latter includes additional damage expressed as MN during the in vitro culture step.

Survival from childhood cancer in northern England, 1968-2005

Background:

Cancer is the second most common cause of death in children in the developed world. The study investigated patterns and trends in survival from childhood cancer in patients from northern England diagnosed 1968–2005.

Methods:

Five-year survival was analysed using Kaplan–Meier estimation for four successive time periods. Cox regression analysis was used to explore associations with age and demographic factors.

Results:

The study included 2958 cases (1659 males and 1299 females). Five-year survival for all cancers improved significantly from 39% in 1968–1977 to 79% in 1998–2005 (P<0.001). Five-year survival for leukaemia increased from 24% to 81% (P<0.001), lymphoma from 46% to 87% (P<0.001), central nervous system tumours from 43% to 73% (P<0.001), bone tumours from 21% to 75% (P<0.001), soft tissue sarcoma from 30% to 58% (P<0.001) and germ cell tumours from 59% to 97% (P<0.001). Survival was worse for cases of acute lymphoblastic leukaemia (P<0.001) and astrocytoma (P<0.001) aged 10–14 years compared with 0–4-year olds.

Conclusion:

There were marked improvements in survival over a 38-year time span. Future work should examine factors that could influence further improvement in survival such as diagnosis delays.

Malignant transformation and stromal invasion from normal or hyperplastic tissues: true or false?

Carcinogenesis is believed to be a multi-step process, progressing sequentially from normal to hyperplastic, to in situ, and to invasive stages. A number of studies, however, have detected malignancy-associated alterations in normal or hyperplastic tissues. As the molecular profile and clinical features of these tissues have not been defined, the authors invited several well-recognized pathologist, oncologists, biologist, surgeons, and molecular biologist to offer their opinion on: (1) whether these tissues belong to a previously unrevealed malignant entity or focal alterations with no significant consequence? (2) whether these alterations are linked to early onset of cancer or cancer of unknown primary site, and (3) how to further define these lesions?

A retrospective study of leukemia epidemiology in Northern Tunisia

A hospital-based epidemiological study of leukemia was carried out in the northern part of Tunisia during a 5-year period, from 1999 to 2003. Of 402 Tunisians diagnosed with leukemia, 344 (85.6%) had acute leukemia and 58 (14.4%) had chronic leukemia. Age-specific incidence rates for acute lymphoid leukemia (ALL), acute myeloid leukemia (AML), chronic lymphoid leukemia (CLL) and chronic myeloid leukemia (CML) are described. The distribution of leukemia in the governorate of Nabeul was established. These results are useful for the organization and follow-up of medical care.

How to minimise the effect of tumour cell content in detection of aberrant genetic markers in neuroblastoma

Background:

Clinical heterogeneity reflects the complexity of genetic events associated with neuroblastoma (NB). To identify the status of all described genetic loci with possible prognostic interest, high-throughput approaches have been used, but only with tumour cell content >60%. In some tumours, necrotic, haemorrhagic and/or calcification areas influence the low amount of neuroblasts. We evaluated the effect of tumour cell content in the detection of relevant aberrant genetic markers (AGM) diagnosed by fluorescence in situ hybridisation (FISH) on tissue microarrays (TMA) in NB.

Methods:

Two hundred and thirty-three MYCN non-amplified primary NB included in 12 TMAs were analysed.

Results:

Presence of AGM reduced event-free survival (EFS) (P=0.004) as well as overall survival (OS) (P=0.004) of patients in the whole cohort. There were no differences in prognostic impact of presence of AGM according to tumour cell content.

Conclusion:

We propose the use of FISH to diagnose AGM of all NB samples having the above-mentioned areas to determine patient risk.

Oncogenic FAM131B-BRAF fusion resulting from 7q34 deletion comprises an alternative mechanism of MAPK pathway activation in pilocytic astrocytoma

Activation of the MAPK signaling pathway has been shown to be a unifying molecular feature in pilocytic astrocytoma (PA). Genetically, tandem duplications at chromosome 7q34 resulting in KIAA1549-BRAF fusion genes constitute the most common mechanism identified to date. To elucidate alternative mechanisms of aberrant MAPK activation in PA, we screened 125 primary tumors for RAF fusion genes and mutations in KRAS, NRAS, HRAS, PTPN11, BRAF and RAF1. Using microarray-based comparative genomic hybridization (aCGH), we identified in three cases an interstitial deletion of ~2.5 Mb as a novel recurrent mechanism forming BRAF gene fusions with FAM131B, a currently uncharacterized gene on chromosome 7q34. This deletion removes the BRAF N-terminal inhibitory domains, giving a constitutively active BRAF kinase. Functional characterization of the novel FAM131B-BRAF fusion demonstrated constitutive MEK phosphorylation potential and transforming activity in vitro. In addition, our study confirmed previously reported BRAF and RAF1 fusion variants in 72% (90/125) of PA. Mutations in BRAF (8/125), KRAS (2/125) and NF1 (4/125) and the rare RAF1 gene fusions (2/125) were mutually exclusive with BRAF rearrangements, with the exception of two cases in our series that concomitantly harbored more than one hit in the MAPK pathway. In summary, our findings further underline the fundamental role of RAF kinase fusion products as a tumor-specific marker and an ideally suited drug target for PA.

Novel associations between activating killer-cell immunoglobulin-like receptor genes and childhood leukemia

Acute lymphoblastic leukemia of pre-B cells (pre-B ALL) is the most frequent form of leukemia affecting children in Western countries. Evidence is accumulating that genetic factors play an important role in conferring susceptibility/resistance to leukemia in children. In this regard, activating killer-cell immunoglobulin-like receptor (KIR) genes are of particular interest. Humans may inherit different numbers of the 6 distinct activating KIR genes. Little is known about the impact of this genetic variation on the innate susceptibility or resistance of humans to the development of B-ALL. We addressed this issue by performing a case-control study in Canadian children of white origin. Our results show that harboring activating KIR genes is associated with reduced risk for developing B-ALL in these children. Of the 6 activating KIR genes, KIR2DS2 was maximally associated with decreased risk for the disease (P = 1.14 × 10(-7)). Furthermore, our results showed that inheritance of a higher number of activating KIR genes was associated with significant reductions in risk for ALL in children. These results were also consistent across different ALL phenotypes, which included children with pre-T cell ALL. Our study provides novel insights concerning the pathogenesis of childhood leukemia in white children and has implications for the development of new immunotherapies for this cancer.

hOGG1 Ser326Cys polymorphism and risk of childhood acute lymphoblastic leukemia in a Chinese population

Oxidative DNA damage caused by reactive oxygen species can produce 8-oxoguanine (8-oxoG) in DNA, which is misread and leads to G:C→T:A transversions. This can be carcinogenic. Repair of 8-oxoG by the base excision repair pathway involves the activity of human 8-oxoG DNA glycosylase 1 (hOGG1). Accumulating evidence suggests that the hOGG1 Ser326Cys polymorphism affects the activity of hOGG1 and might serve as a genetic marker for susceptibility to several cancers. To determine whether this polymorphism is associated with risk of childhood acute lymphoblastic leukemia (ALL) in Chinese children, we genotyped the hOGG1 Ser326Cys polymorphism (rs1052133) in a case-control study including 415 cases and 511 controls. We found that there was a significant difference in the genotype distributions of the hOGG1 Ser326Cys polymorphism between cases and controls (P = 0.046), and the combined genotypes Ser/Ser and Ser/Cys were associated with a statistically significantly decreased risk of ALL (adjusted odds ratio [OR] = 0.66, 95% confidence interval [CI] = 0.49-0.88, P = 0.005). Furthermore, we found a decreased risk for high risk ALL (adjusted OR = 0.60, 95% CI = 0.40-0.88, P = 0.005), low risk ALL (adjusted OR = 0.68, 95% CI = 0.47-0.99, P = 0.042), and B-phenotype ALL (adjusted OR = 0.63, 95% CI = 0.46-0.86, P = 0.003) among children with the Ser/Ser and Ser/Cys genotypes. Our results suggest that the hOGG1 Ser326Cys polymorphism is associated with susceptibility to childhood ALL in a Chinese population.

[Environment and paediatric cancer in the Region of Murcia (Spain): integrating clinical and environmental history in a geographic information system]

INTRODUCTION

Environment and Paediatric Cancer (PC) in the Region of Murcia (RM) is an on-going research project that has the following aims: to collect a careful paediatric environmental history (PEH) and to use geographical information systems (GIS) to map the incidence and analyze the geographic distribution of the PC incidence in the RM. The objectives are to present the methodology used for the collection and processing of data and disseminate initial results on the spatial and temporal incidence of PC in the RM (Spain).

MATERIAL AND METHODS

A descriptive and georeference study of all PC cases under 15 years, diagnosed from 1 January 1998 to December 31, 2009. Three postal addresses were assigned to each case, residence during pregnancy, postnatal, and at the time of diagnosis. Other variables such as sex, date of birth, date of diagnosis, and histopathology classification were collected.

RESULTS

No increase was observed in the trend of incidence of PC. The crude annual incidence rate was 14.3 cases per 100,000 children under 15 years. The standardised incidence ratio was higher in the north-west of the RM. Before diagnosis, 30% of cases had a different postal address than during the pregnancy.

CONCLUSIONS

Integrating the spatial and temporal information through the PEH in a GIS should allow the identification and study of space-time clusters through an environmental monitoring system in order to know the importance of associated risk factors.

Apoptotic induction in B-cell acute lymphoblastic leukemia cell lines treated with a protein kinase Cβ inhibitor

B-cell acute lymphoblastic leukemia (B-ALL) in adults exhibits a 5-year disease-free survival rate of only 25-40% after currently available treatment. Protein kinase Cβ (PKCβ) is under active consideration as a rational therapeutic target in several B-cell malignancies, but studies of its possible utility in B-ALL are lacking. Expression of PKCβ1 and PKCβ2 isoforms was demonstrated in five B-ALL cell lines characterized by distinctive chromosomal translocations, and sensitivity to PKCβ-selective inhibition was examined. Inhibitor treatment resulted in a dose-dependent reduction in viability in all cell lines, although pro-B ALL with t(4;11)(q21;q23) was most sensitive. Apoptotic induction was evident after 24-48 h of treatment, and an inhibition of cell cycle progression was detected in one cell line. Treatment resulted in a rapid induction of poly(ADP-ribose) polymerase (PARP) cleavage, indicating caspase-3-mediated apoptosis, and a rapid reduction in phosphorylation of AKT and its downstream target glycogen synthase kinase 3β (GSK3β). These results indicate that PKCβ targeting should be considered as a potential treatment option in B-ALL.

Complementary and alternative medicine use among pediatric patients with leukemia: the case of Lebanon

BACKGROUND

International evidence indicates that caretakers of pediatric leukemia patients are increasingly using complementary and alternative medicine (CAM) therapies. Such a trend has never been substantiated in the Arab world.

OBJECTIVE

Examine the frequency, types, modes, and reasons of CAM use among pediatric leukemia patients in Lebanon.

METHODS

A cross-sectional design was utilized to survey (by phone) the caregivers of all pediatric leukemia patients on the rosters of the 2 largest cancer treatment facilities in Lebanon for years 2005-2009. A total of 125 parents out of 175 (71.4%) completed the questionnaire, which included 3 sections: socio-demographic characteristics, clinical information and CAM use details. Data analysis employed univariate descriptive statistics, t-test, and χ(2)

RESULTS

Overall, 15.2% of respondents reported using one or more CAM therapies for their child (95% confidence interval: 8.9% to 22.0%). The main CAM therapies used included dietary supplements, prayer/spiritual healing, and unconventional cultural practices (ingesting bone ashes). CAM therapies were used for strengthening immunity (42.1%) and improving the chance of cure (21%). Pediatric users of CAM were 2 years older than nonusers and had been diagnosed with leukemia for a longer period of time (4.76 ± 3.24 vs 3.49 ± 2.38, P<.05). The percentage of males among CAM users was higher than that among nonusers (89.5% vs 56.6%, P<.05).

CONCLUSION

Increasing awareness of both caretakers and physicians of pediatric leukemia patients on the effects and risks of CAM therapies is essential should rational, safe, and evidence-based utilization of CAM therapies be achieved.

Childhood cancer survival: a report from the United Kingdom Childhood Cancer Study

BACKGROUND

Improvements in diagnostic approaches and refinements to treatment protocols have resulted in 5-year survival levels above 70% for children diagnosed with cancer in economically developed parts of the world. For some cancers, including leukaemia and tumours of the central nervous system, age and sex have been identified as important prognostic indicators.

METHODS

We examined long-term survival, and affects of age and sex, in a population-based case-control study. Children (0-14 years) newly diagnosed with cancer were ascertained between 1991 and 1996 (n=4433). Follow-up information was obtained from the National Health Service (NHS) Information Centre for Health and Social Care which records all exits from the NHS including deaths.

RESULTS

For all cancer diagnoses combined, 5-year survival was 72.7% dropping to 67.9% at 15 years. As expected, survival differed between diagnostic subtypes ranging from 38.1% for intracranial embryonal tumours to 96.2% for Hodgkin lymphoma. Compared to girls, boys diagnosed with acute lymphoblastic leukaemia were at a higher risk of dying (RR=1.26, 95% CI 1.03-1.53), whereas boys diagnosed with an intracranial embryonal tumour were at a lower risk of death (RR=0.63, 95% CI 0.43-0.91).

CONCLUSION

Our initial findings are consistent with previous reports, and highlight the importance of considering differences by age and sex. The completeness and population-based nature of the original case-control study is an important feature which will provide the basis for future more detailed investigations linking disease determinants to outcome.