Embryonal tumors in Canadian children less than 36 months of age: results from the Canadian Pediatric Brain Tumor Consortium (CPBTC)

Embryonal tumors are a heterogeneous group of central nervous system (CNS) tumors whose subgroups have varying incidence and outcome. Despite these differences, they are often grouped as a single entity for study purposes. To date, there are no Canadian multi-institutional studies examining the incidence and outcome of all embryonal subtypes. The current study is an observational study reviewing embryonal tumors in all patients less than 36 months of age diagnosed with a CNS tumor in Canada from 1990 to 2005. Embryonal tumors accounted for 26.9% of all CNS tumors. Medulloblastomas were the highest proportion of the embryonal tumors at 61.5%. Atypical teratoid/rhabdoid tumors (AT/RT) had the second highest proportion of embryonal tumors at 18%. The proportion of primitive neuroectodermal tumors (PNET) was 16%, with 2.6 and 1.9% for congenital medulloepithelioma and ependymoblastoma tumors, respectively. AT/RT and PNET were more common in younger age groups. Medulloblastoma became more prevalent with increasing age, with its highest prevalence in the 25 to 36 month age group. Survival rates for our Canadian population at 18 and 24 months were 0.74 and 0.68 for medulloblastoma, 0.64 and 0.60 for PNET, and 0.36 and 0.29 for AT/RT, respectively. Overall, our data are comparable with published international rates for embryonal tumors. These incidence and outcome figures can guide future research into these rare tumors.

Single nucleotide polymorphism in IL1B is associated with infection risk in paediatric acute myeloid leukaemia

We evaluated single nucleotide polymorphisms (SNPs) associated with infection risk in children with newly diagnosed acute myeloid leukaemia (AML). We conducted a multicentre, prospective cohort study that included children aged ≤18 years with de novo AML. DNA was isolated from blood lymphocytes or buccal swabs, and candidate gene SNP analysis was conducted. Primary outcome was the occurrence of microbiologically documented sterile site infection during chemotherapy. Secondary outcomes were Gram-positive and -negative infections, viridans group streptococcal infection and proven/probable invasive fungal infection. Interpretation was guided by consistency in risk alleles and microbiologic agent with previous literature. Over the study period 254 children and adolescents with AML were enrolled. Overall, 190 (74.8%) had at least one sterile site microbiologically documented infection. Among the 172 with inferred European ancestry and DNA available, nine significant associations were observed; two were consistent with previous literature. Allele A at IL1B (rs16944) was associated with decreased microbiologically documented infection, and allele G at IL10 (rs1800896) was associated with increased risk of Gram-positive infection. We identified SNPs associated with infection risk in paediatric AML. Genotype may provide insight into mechanisms of infection risk that could be used for supportive-care novel treatments.

Does the use of the revised psychosocial assessment tool (PATrev) result in improved quality of life and reduced psychosocial risk in Canadian families with a child newly diagnosed with cancer?

OBJECTIVES

Early psychosocial screening may guide interventions and ameliorate the adverse psychosocial effects of childhood cancer. The revised psychosocial assessment tool provides risk information - Universal (typical distress), Targeted (additional specific distress), and Clinical (severe distress) - about the child with cancer and his or her family. This pilot study investigated the benefits of providing a summary of family psychosocial risk information to the medical team treating the newly diagnosed child (Experimental Group, EG).

METHOD

We conducted a pilot randomized control trial with a sample of 67 parents, comparing the EG to the control group (CG) on parental perception of family psychosocial difficulties (revised psychosocial assessment tool risk levels), child behavior (behavior assessment scale for children-2), pediatric quality of life (PedsQL), and parental anxiety (state-anxiety scale of the state-trait anxiety inventory ), 2-4 weeks after diagnosis (Time 1) and 6 months later (Time 2).

RESULTS

Compared to the CG, participants in the EG had significantly reduced targeted and clinical risk (p < 0.001), and improved pain related PedsQL at Time 2 (p < 0.05). Scores for PedsQL total and nearly all subscales improved over time in both groups (p < 0.05 to p < 0.001). No changes in behavior scores were noted.

CONCLUSION

Preliminary findings suggest that providing a summary of the Psychosocial Assessment Tool to the treating team shortly after diagnosis may help reduce family wide psychosocial risk 6 months later and improve quality of life related to pain for children who are undergoing treatment for cancer.

Central nervous system atypical teratoid rhabdoid tumours: the Canadian Paediatric Brain Tumour Consortium experience

BACKGROUND

Atypical teratoid rhabdoid tumours (ATRT) are aggressive brain tumours mostly occurring in early childhood. Largest published series arise from registries and institutional experiences (1-4). The aim of this report is to provide population-based data to further characterise this rare entity and to delineate prognostic factors.

PATIENTS AND METHODS

A national retrospective study of children ⩽18years diagnosed with a central nervous system (CNS) ATRT between 1995 and 2007 was undertaken. All cases underwent central pathology review.

RESULTS

There were 50 patients (31 males; median age at diagnosis of 16.7months). Twelve patients were >36months. Infratentorial location accounted for 52% of all cases. Nineteen patients (38%) had metastatic disease. Fifteen (30%) underwent gross total resection (GTR). Ten patients (20%) underwent palliation. Among the 40 remaining patients, 22 received conventional chemotherapy and 18 received high dose chemotherapy regimens (HDC); nine received intrathecal chemotherapy and 15 received adjuvant radiation. Thirty of the 40 treated patients relapsed/progressed at a median time of 5.5months (0-32). The median survival time of the entire cohort was 13.5months (1-117.5months). Age, tumour location and metastatic status were not prognostic. Patients with GTR had a better survival (2years overall survival (OS): 60%±12.6 versus 21.7%±8.5, p=0.03). HDC conferred better outcome (2years OS 47.9%±12.1 versus 27.3%±9.5, p=0.036). Upfront radiation did not provide survival benefit. Six of the 12 survivors (50%) did not receive radiation.

CONCLUSION

The outcome of CNS ATRT remains poor. However, the use of HDC provides encouraging results. GTR is a significant prognostic factor. The role of adjuvant radiation remains unclear.

The use and effectiveness of temozolomide in children with central nervous system tumours: a survey from the Canadian Paediatric Brain Tumour Consortium

OBJECTIVE

To describe the use of temozolomide (tmz) in Canadian children treated for brain tumours and to evaluate survival and predictors of survival for children treated with this agent.

METHODS

A survey was conducted within the Canadian Paediatric Brain Tumour Consortium (cpbtc), a group of tertiary care centres in pediatric neuro-oncology (n = 16) in Canada that are involved in the treatment of children with central nervous system tumours.

RESULTS

In 10 of the 16 participating pediatric oncology centres of the cpbtc, 137 children with brain tumours were treated with tmz between January 2000 and March 2006. Although 33% of the children were enrolled into a clinical trial, 67% were treated outside open studies. Most patients (72%) received tmz treatment on recurrence of their brain tumour (first or subsequent). The most commonly administered regimen was single-agent tmz 150-200 mg/m(2) administered on 5 consecutive days every 28 days. The median duration of tmz treatment was 141 days (range: 4-1102 days). Response data were provided for 127 of the 137 patients, of whom 6 showed a complete response. Sixteen patients experienced a minor or partial response, 53 had stable disease, and 52 had progressive disease. Of 32 patients alive at last follow-up, 19 had a diagnosis of low-grade glioma.

CONCLUSIONS

Temozolomide is used in a variety of pediatric brain tumours, often at the time of recurrence. The lack of insight into clear indications for this agent in pediatric brain tumours-used either alone or in combination therapy-may be a result of suboptimal design of phase i and ii studies and a lack of phase iii trials in the pediatric brain tumour population.

Impaired endothelial function in Hodgkin lymphoma survivors receiving mediastinal radiation

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Background: Mediastinal radiation (RT) is a cause of premature coronary artery disease (CAD) in Hodgkin lymphoma survivors (HLS). Early detection of atherosclerosis may allow for improved health outcomes. Peripheral arterial tonometry (PAT) is a non-invasive technique that measures endothelial function (EF), as a surrogate marker of sub-clinical atherosclerosis. The objective of our study was to evaluate EF in HLS and age-matched controls using PAT and to determine the association of mediastinal RT. Methods: Cross sectional evaluation of 26 HLS age 12–30 years and within a minimum of two years from the completion of therapy and matched controls. Evaluation for CAD risk factors included measurement of body mass index and blood pressure, fasting lipoproteins and hsCRP. A standardized activity questionnaire (HAES, habitual activity estimation score) was completed by all participants. EF was measured using PAT hyperemia ratios (PAT-HR) in all subjects. Results: HLS and controls were similar for baseline variables (mean age 23.2 ± 5 yrs; 23.4 ± 4.6 yrs, p=0.35). HLS were on average 9.9 ± 3.9 yrs post treatment. No differences in EF or cardiovascular risk factors were observed between HLS survivors and controls. However impaired EF, as evidenced by lower PAT-HR (1.66 ± 0.18 vs. 2.08 ± 0.38, p<0.01) was seen in HLS (n=13) who received mantle/mediastinal RT (mean RT dose 2657 ± 971 cGy) compared to controls. Mean cumulative anthracycline dose did not differ between HLS who did or did not receive RT (224.1 ± 65.4 vs. 253 ± 70.3 mg/m2 p=0.18). These differences were not explained by alterations in lipoproteins or hsCRP, however activity scores were significantly lower in HLS compared with young adult controls (2.01 ± 1.1 vs. 3.6 ± 1.2 hrs daily, p=0.02). Conclusions: Impaired EF was observed in a small group of HLS who received mediastinal RT as compared to those who did not. Cancer survivors at risk may benefit from early assessment of EF as a sub-clinical marker of CAD.

No significant financial relationships to disclose.

Epidemiological survey of central nervous system germ cell tumors in Canadian children

OBJECTIVES

To determine the incidence and characteristics of pediatric patients with central nervous system (CNS) germ cell tumors (GCT) in Canada.

METHOD

A national retrospective review of hospital charts was done on all patients with CNS GCT diagnosed between 1990 and 2004. Patients had to be under age 18 years at the time of diagnosis of a CNS germ cell tumor and be a resident of Canada. Information extracted included age and year of diagnosis, pathological diagnosis, location of tumor, evidence of disseminated disease at time of diagnosis and biological markers.

RESULTS

One hundred and twenty-one cases were identified (83 germinoma; 38 non-germinoma germ cell tumor). The mean annual incidence of CNS GCT was 1.06 per million children (0.7 per million for germinoma; 0.3 per million for NGGCT). Though yearly incidences varied, there was no clear trend to increased incidence. Male predominance was noted (2.4:1 for germinoma; 11:1 for NGGCT). The primary locations were the pineal and suprasellar regions. At the time of diagnosis, disseminated disease was not uncommon (22% germinoma; 32% NGGCT). Beta human gonadotrophin was elevated in the serum, cerebrospinal fluid (CSF) or both in 7% of patients with germinoma and 36% of patients with NGGCT. Elevation of alpha-fetoprotein in serum, CSF or both was seen in 34% of patients with NGGCT.

CONCLUSION

The incidence of CNS germ cell tumors in Canadian children is similar to that observed in other Western countries.

Carboplatin hypersensitivity reaction in pediatric low grade glioma (LGG) patients: A national experience. On behalf of the Canadian Pediatric Brain Tumor Consortium

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Background: Carboplatin based regimens are widely used in the treatment of unresectable pediatric LGG. Carboplatin hypersensitivity reaction (CHSR) represents a main limiting factor. Objective: To analyse the incidence, characteristics, management and impact on outcome of CHSR. Methods: National retrospective review of children diagnosed with LGG between 1988 and 2004. Inclusion criteria were age <18 years, pathology proven diagnosis of LGG except in NF1 patients, and no chemotherapy or radiotherapy prior to carboplatin chemotherapy. Results: 105 patients (61F/44M) from 10 Canadian centers were included in the study. Median age at diagnosis was 3.5y (0.3–16.8). 33 patients had NF1, 75 had diencephalic tumor. Carboplatin was given monthly or weekly respectively in 46 and 59 patients. 44 (41.9%) patients developed carboplatin HSR at a median time of 6.5 months (0.4–15.4), after a median number of 10.5 (3–39) injections. CHSR occurred significantly earlier with the weekly schedule (p=0.016). Cumulative incidence of CHSR increased with the number of injections with no plateau. Female had significant higher risk to develop CHSR (p=0.02) whereas age, NF1 status and schedule of administration were not significant risk factors. First allergic reaction was rated grade I, II in 36 patients (82%). 34 patients were reexposed to carboplatin with desensitization/premedication, allowing 14 patients (41.2%) to complete their treatment. But the majority (58.8%) had recurrent allergic reaction with a significant worsening of their symptoms (p=0.039). The median number of additional Carboplatin injections delivered was 4 (0.5–34). After Carboplatin discontinuation, 18 patients were switched to another chemotherapy regimen. 5 years PFS was not significantly different in allergic and non allergic patients (53.9% and 45.6%). Conclusions: In our experience, the incidence of CHSR is high (41.9%). Female have higher risk of CHSR. Desensitization/premedication has limited efficacy and does not prevent worsening of CHSR. CHSR did not impact the PFS. However many patients did switch to another chemotherapy regimen and the total duration of treatment was comparable in both groups.

No significant financial relationships to disclose.