Risk factors associated with nausea and vomiting in children with cancer receiving chemotherapy.

INTRODUCTION: Despite treatment with antiemetic medications, nausea remains uncontrolled for many children receiving chemotherapy. One reason is that risk factors for nausea in children remain poorly explored. The purpose of this study was to identify risk factors for chemotherapy-induced nausea (CIN) in children. METHODS: Prospective, observational study including 101 children (median age 6.4 years, range 0.8-17.9) with cancer receiving moderately or highly emetogenic chemotherapy. Primary endpoints were complete control of acute and delayed CIN, defined as no nausea in the acute phase 0-24 h after chemotherapy and in the delayed phase starting after the acute phase and ending 5 days later. Multivariable analyses included age, sex, cancer type, susceptibility to motion sickness, chemotherapy duration, numbers of antiemetics, co-administration with opioids or tricyclic antidepressants, and previously uncontrolled nausea or vomiting. RESULTS: Acute CIN was associated with susceptibility to motion sickness (odds ratio [OR] 5.73, 95% confidence interval [CI] 1.36-33.7) and older age (OR 4.19, 95% CI 1.30-14.7), comparing age group 8-18 years with 0-3 years. Delayed CIN was associated with uncontrolled acute nausea or vomiting (OR 10.3, 95% CI 2.65-50.9), highly emetogenic chemotherapy (OR 8.26, 95% CI 1.17-76.8), and having a hematologic cancer type (OR 7.81, 95% CI 1.05-79.2). CONCLUSIONS: Susceptibility to motion sickness and age can influence the risk of acute CIN. More research is needed on how best to integrate risk information in preventive antiemetic strategies. Sufficient acute nausea and vomiting control are crucial to prevent delayed CIN.

Postoperative speech impairment and cranial nerve deficits after secondary surgery of posterior fossa tumours in childhood: a prospective European multicentre study.

PURPOSE: Brain tumours constitute 25% of childhood neoplasms, and half of them are in the posterior fossa. Surgery is a fundamental component of therapy, because gross total resection is associated with a higher progression-free survival. Patients with residual tumour, progression of residual tumour or disease recurrence commonly require secondary surgery. We prospectively investigated the risk of postoperative speech impairment (POSI) and cranial nerve dysfunction (CND) following primary and secondary resection for posterior cranial fossa tumours. METHODS: In the Nordic-European study of the cerebellar mutism syndrome, we prospectively included children undergoing posterior fossa tumour resection or open biopsy in one of the 26 participating European centres. Neurological status was assessed preoperatively, and surgical details were noted post-operatively. Patients were followed up 2 weeks, 2 months and 1 year postoperatively. Here, we analyse the risk of postoperative speech impairment (POSI), defined as either mutism or reduced speech, and cranial nerve dysfunction (CND) following secondary, as compared to primary, surgery. RESULTS: We analysed 426 children undergoing primary and 78 undergoing secondary surgery between 2014 and 2020. The incidence of POSI was significantly lower after secondary (12%) compared with primary (28%, p = 0.0084) surgery. In a multivariate analysis adjusting for tumour histology, the odds ratio for developing POSI after secondary surgery was 0.23, compared with primary surgery (95% confidence interval: 0.08-0.65, p = 0.006). The frequency of postoperative CND did not differ significantly after primary vs. secondary surgery (p = 0.21). CONCLUSION: Children have a lower risk of POSI after secondary than after primary surgery for posterior fossa tumours but remain at significant risk of both POSI and CND. The present findings should be taken in account when weighing risks and benefits of secondary surgery for posterior fossa tumours.

Whole blood long-chain n-3 fatty acids as a measure of fish oil compliance in children with acute lymphoblastic leukemia: a pilot study.

Long-chain n-3 fatty acids (n-3 LCPUFA) may prevent chemotherapy-induced hyperlipidemia in children with acute lymphoblastic leukemia (ALL). However, compliance could be a problem and intake-biomarker correlations may be affected by bodyweight and blood transfusions. We assessed whole blood n-3 LCPUFA three times during the first 83 days of treatment in six 1-17-year-old children with ALL, who received 2.4-4.9 g/d n-3 LCPUFA depending on bodyweight. Mean compliance was 73%, which resulted in a 2.5-fold increase in blood n-3 LCPUFA irrespective of blood transfusions. The correlation between relative blood content of n-3 LCPUFA and intake in g/d across the study period was strong (r=0.76, p=0.001). When n-3 LCPUFA was expressed in absolute concentrations and intake per kg bodyweight the correlation decreased (r=0.39, p=0.164) and was driven by baseline values. Thus, relative content of n-3 LCPUFA in blood reflects fish oil compliance in children with ALL despite blood transfusions and differences in bodyweight.

Parenthood among men diagnosed with cancer in childhood and early adulthood: trends over time in a Danish national cohort.

STUDY QUESTION: Is the rate of fatherhood among men diagnosed with cancer in childhood and early adulthood different from men without cancer, and, if so, have the differences changed over time? SUMMARY ANSWER: Men diagnosed with cancer have had significantly reduced rates of fatherhood compared with undiagnosed men; however, the rates of fatherhood among the cancer survivors have increased markedly over time. WHAT IS KNOWN ALREADY: The number of children and young adolescents who survive cancer has steadily increased over recent decades, with a current 5-year survival rate of approximately 80%. Consequently, life circumstances after cancer have gained increasing importance, including the desire among survivors to have children and a family. ARTs to aid reproduction among cancer survivors have been developed, and fertility preservation is increasingly a topic being discussed before undergoing cancer treatment. But the potential for fertility preservation differs dependent on age at diagnosis and type of cancer. Earlier studies have shown a decreased fertility rate among survivors of child and adolescent cancer compared to those diagnosed in early adulthood. STUDY DESIGN, SIZE, DURATION: This study is a national, register-based cohort study. Men diagnosed with cancer in childhood and early adulthood (<30 years of age) were registered in the Danish Cancer Register in 1978-2016 (n = 9353). According to the time of diagnosis, each cancer-diagnosed man was randomly matched with 150 undiagnosed men from the background population within the same birth year. The men were followed until having their first child, death, migration or the end of the study (31 December 2017) in medical registers and socio-demographic population registers. PARTICIPANTS/MATERIALS, SETTING, METHODS: Fatherhood among the boys and young men diagnosed with cancer were compared with the age-matched comparison group in all statistical analyses. Cancer diagnoses were categorised as central nervous system (CNS) cancers, haematological cancers or solid cancers. Analyses were stratified by age at diagnosis (0-9, 10-19, 20-29 years) and time of diagnosis (1978-1989, 1990-1999, 2000-2009, 2010-2016). Death was incorporated as a competing risk in all analyses. MAIN RESULTS AND THE ROLE OF CHANCE: The study population consisted of 9353 boys and young men diagnosed with cancer between 1978 and 2016 and 1 386 493 men in the age-matched comparison group. Those surviving CNS cancer as young men had the lowest hazard ratio (HR) of fatherhood compared with the age-matched comparison group (HR 0.67, 95% CI 0.57-0.79), followed by survivors of haematological cancers (HR 0.90, 95% CI 0.81-1.01), while the highest chance of fatherhood was among survivors of solid cancers (HR 1.16, 95% CI 1.12-1.20) with a slightly increased HR compared with undiagnosed males. The HR of becoming a father increased over time. From the first decade to the last decade 30 years later, the HR of becoming a father increased for solid tumours (HR 0.78, 95% CI 0.73-0.83 to HR 1.08, 95% CI 0.95-1.22), haematological cancers (HR 0.64, 95% CI 0.53-0.79 to HR 0.97, 95% CI 0.73-1.30) and CNS cancers (HR 0.44, 95% CI 0.34-0.57 to HR 0.98, 95% CI 0.49-1.95) compared to the age-matched comparison group. Also, when compared with the age-matched comparison group, men diagnosed with cancer when aged 20-29 years were more likely became fathers over the time of the study (HR 0.80, 95% CI 0.74-0.86 to HR 1.08, 95% CI 0.96-1.22). LIMITATIONS, REASONS FOR CAUTION: The study was based on register data, and information was not available about the men's fertility potential, whether they had a desire to have children and whether it was possible for them to find a partner. Information about fertility preservation, e.g. sperm freezing, could also have provided additional insights. Furthermore, information about diagnosis and ART treatment would have been beneficial. WIDER IMPLICATIONS OF THE FINDINGS: Information and education of male patients diagnosed with cancer about fertility preservation options and their chances to create their own family is crucial. Reassuringly, time trends showed more men with a previous cancer diagnosis becoming fathers in recent years than in earlier years, reflecting that survival and fertility preservation have improved over time. STUDY FUNDING/COMPETING INTEREST(S): R.S. received a PhD grant from the Rosa Ebba Hansen Foundation and from the Health Foundation (J.nr. 15-B-0095). The funding for the establishment of the DANAC II Cohort was obtained from the Rosa Ebba Hansen Foundation. The authors have no conflicts of interest to declare. TRIAL REGISTRATION NUMBER: N/A.

Value of flow cytometry for MRD-based relapse prediction in B-cell precursor ALL in a multicenter setting.

PCR of TCR/Ig gene rearrangements is considered the method of choice for minimal residual disease (MRD) quantification in BCP-ALL, but flow cytometry analysis of leukemia-associated immunophenotypes (FCM-MRD) is faster and biologically more informative. FCM-MRD performed in 18 laboratories across seven countries was used for risk stratification of 1487 patients with BCP-ALL enrolled in the NOPHO ALL2008 protocol. When no informative FCM-marker was available, risk stratification was based on real-time quantitative PCR. An informative FCM-marker was found in 96.2% and only two patients (0.14%) had non-informative FCM and non-informative PCR-markers. The overall 5-year event-free survival was 86.1% with a cumulative incidence of relapse (CIR5y) of 9.5%. FCM-MRD levels on days 15 (HzR 4.0, p < 0.0001), 29 (HzR 2.7, p < 0.0001), and 79 (HzR 3.5, p < 0.0001) associated with hazard of relapse adjusted for age, cytogenetics, and WBC. The early (day 15) response associated with CIR5y adjusted for day 29 FCM-MRD, with higher levels in adults (median 2.4 × 10-2 versus 5.2 × 10-3, p < 0.0001). Undetectable FCM- and/or PCR-MRD on day 29 identified patients with a very good outcome (CIR5y = 3.2%). For patients who did not undergo transplantation, day 79 FCM-MRD > 10-4 associated with a CIR5y = 22.1%. In conclusion, FCM-MRD performed in a multicenter setting is a clinically useful method for MRD-based treatment stratification in BCP-ALL.

T-cell acute lymphoblastic leukemia in patients 1-45 years treated with the pediatric NOPHO ALL2008 protocol.

The NOPHO ALL2008 is a population-based study using an unmodified pediatric protocol in patients 1-45 years of age with acute lymphoblastic leukemia. Patients with T-ALL were given a traditional pediatric scheme if fast responding (minimal residual disease (MRD) < 0.1% day 29), or intensive block-based chemotherapy if slow responding (MRD > 0.1% day 29). Both treatment arms included pediatric doses of high-dose methotrexate and asparaginase. If MRD ≥ 5% on day 29 or ≥0.1% after consolidation, patients were assigned to allogeneic hematopoietic stem cell transplantation. The 5-year overall survival of the 278 T-ALL patients was 0.75 (95% CI 0.69-0.81), being 0.82 (0.74-0.88) for patients 1.0-9.9 years, 0.76 (0.66-0.86) for those 10.0-17.9 years, and 0.65 (0.55-0.75) for the older patients. The risk of death in first remission was significantly higher in adults (12%) compared with the 1-9 years group (4%). The MRD responses in the three age groups were similar, and only a nonsignificant increase in relapse risk was found in adults. In conclusion, an unmodified pediatric protocol in patients 1-45 years is effective in all age groups. The traditional pediatric treatment schedule was safe for all patients, but the intensive block therapy led to a high toxic death rate in adults.

Correction: Minimal residual disease quantification by flow cytometry provides reliable risk stratification in T-cell acute lymphoblastic leukemia.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Minimal residual disease quantification by flow cytometry provides reliable risk stratification in T-cell acute lymphoblastic leukemia.

Minimal residual disease (MRD) measured by PCR of clonal IgH/TCR rearrangements predicts relapse in T-cell acute lymphoblastic leukemia (T-ALL) and serves as risk stratification tool. Since 10% of patients have no suitable PCR-marker, we evaluated flowcytometry (FCM)-based MRD for risk stratification. We included 274 T-ALL patients treated in the NOPHO-ALL2008 protocol. MRD was measured by six-color FCM and real-time quantitative PCR. Day 29 PCR-MRD (cut-off 10-3) was used for risk stratification. At diagnosis, 93% had an FCM-marker for MRD monitoring, 84% a PCR-marker, and 99.3% (272/274) had a marker when combining the two. Adjusted for age and WBC, the hazard ratio for relapse was 3.55 (95% CI 1.4-9.0, p = 0.008) for day 29 FCM-MRD ≥ 10-3 and 5.6 (95% CI 2.0-16, p = 0.001) for PCR-MRD ≥ 10-3 compared with MRD < 10-3. Patients stratified to intermediate-risk therapy on day 29 with MRD 10-4-<10-3 had a 5-year event-free survival similar to intermediate-risk patients with MRD < 10-4 or undetectable, regardless of method for monitoring. Patients with day 15 FCM-MRD < 10-4 had a cumulative incidence of relapse of 2.3% (95% CI 0-6.8, n = 59). Thus, FCM-MRD allows early identification of patients eligible for reduced intensity therapy, but this needs further studies. In conclusion, FCM-MRD provides reliable risk prediction for T-ALL and can be used for stratification when no PCR-marker is available.

Results of NOPHO ALL2008 treatment for patients aged 1-45 years with acute lymphoblastic leukemia.

Adults with acute lymphoblastic leukemia (ALL) do worse than children. From 7/2008 to 12/2014, Nordic and Baltic centers treated 1509 consecutive patients aged 1-45 years with Philadelphia chromosome-negative ALL according to the NOPHO ALL2008 without cranial irradiation. Overall, 1022 patients were of age 1-9 years (A), 266 were 10-17 years (B) and 221 were 18-45 years (C). Sixteen patients (three adults) died during induction. All others achieved remission after induction or 1-3 intensive blocks. Subsequently, 45 patients (12 adults) died, 122 patients relapsed (32 adults) with a median time to relapse of 1.6 years and 13 (no adult) developed a second malignancy. Median follow-up time was 4.6 years. Among the three age groups, older patients more often had higher risk ALL due to T-ALL (32%/25%/9%, P<0.001), KMT2A rearrangements (6%/5%/3%, P<0.001) and higher day 29 residual leukemia for B-lineage (P<0.001), but not T-ALL (P=0.53). Event-free survival rates (pEFS5y) were 89±1% (A), 80±3% (B) and 74±4% (C) with significant differences only for non-high risk groups. Except for thrombosis, pancreatitis and osteonecrosis, the risk of 19 specified toxicities was not enhanced by age above 10 years. In conclusion, a pediatric-based protocol is tolerable and effective for young adults, despite their increased frequency of higher risk features.

Asparaginase-associated pancreatitis: a study on phenotype and genotype in the NOPHO ALL2008 protocol.

Asparaginase (ASP)-associated pancreatitis (AAP) occurs during acute lymphoblastic leukemia treatment. Among 1285 children (1.0-17.9 years) diagnosed during July 2008-December 2014 and treated according to the Nordic/Baltic ALL2008 protocol, 86 (cumulative incidence=6.8%) developed AAP. Seventy-three cases were severe (diagnostic AAP criteria persisting >72 h) and 13 mild. Cases were older than controls (median: 6.5 vs 4.5 years; P=0.001). Pseudocysts developed in 28%. Of the 20 re-exposed to ASP, 9 (45%) developed a second AAP. After a median follow-up of 2.3 years, 8% needed permanent insulin therapy, and 7% had recurrent abdominal pain. Germline DNA on 62 cases and 638 controls was genotyped on Omni2.5exome-8-v1.2 BeadChip arrays. Overall, the ULK2 variant rs281366 showed the strongest association with AAP (P=5.8 × 10-7; odds ratio (OR)=6.7). Cases with the rs281366 variant were younger (4.3 vs 8 years; P=0.015) and had lower risk of AAP-related complications (15% vs 43%; P=0.13) compared with cases without this variant. Among 45 cases and 517 controls <10 years, the strongest associations with AAP were found for RGS6 variant rs17179470 (P=9.8 × 10-9; OR=7.3). Rs281366 is located in the ULK2 gene involved in autophagy, and RGS6 regulates G-protein signaling regulating cell dynamics. More than 50% of AAP cases <10 years carried one or both risk alleles.

Facilitation of school re-entry and peer acceptance of children with cancer: a review and meta-analysis of intervention studies.

Increased survival rates from childhood cancer call for efforts to reintegrate children with cancer back into their academic and social environments. The aims of this study were to: (1) review and analyse the existing literature on school re-entry interventions for children with cancer; and (2) discuss the importance of peer involvement in the treatment. Relevant databases were searched using equivalent search algorithms and six studies were selected that target children with cancer and/or their classmates. Two authors independently reviewed the literature for data extraction. The articles were reviewed using the PRISMA model for reporting reviews. Statistical calculations for the meta-analyses were done using Review Manager 5.2. The meta-analyses showed significant effects of school re-entry programmes in terms of enhancing academic achievement in children with cancer (P = 0.008) and lowering their levels of depression (P = 0.05). Increased knowledge among classmates was associated with less fear and a more positive attitude towards the child with cancer. Due to limited numbers of patients, lack of control groups, and the diversity of intervention strategies used in previous studies, there is a need for intervention programmes exploring the optimal path for the reintegration of children with cancer into the education system and into their peer groups.

Peripherally applied opioids for postoperative pain: evidence of an analgesic effect? A systematic review and meta-analysis.

BACKGROUND: Opioids applied peripherally at the site of surgery may produce postoperative analgesia with few side effects. We performed this systematic review to evaluate the analgesic effect of peripherally applied opioids for acute postoperative pain. METHODS: We searched PubMed (1966 to June 2013), Embase (1980 to June 2013), and the Cochrane Central Register of Controlled Trials (The Cochrane Library 2013, Issue 6). Randomized controlled trials investigating the postoperative analgesic effect of peripherally applied opioids vs. systemic opioids or placebo, measured by pain intensity scores, consumption of supplemental analgesics and time to first analgesic were included. Trials with sample sizes of fewer than 10 patients per treatment group or trials with opioids administered intra-articularly or as peripheral nerve blocks were excluded. RESULTS: Data from 26 studies, including 1531 patients and 13 different surgical interventions were included. Clinical heterogeneity of the studies was substantial. Meta-analysis indicated statistically significant, but not clinically relevant, reductions in VAS score at 6-8 h (mean difference -4 mm, 95% CI: -6 to -2) and 12 h postoperatively (mean difference -5 mm, 95% CI: -7 to -3) for peripherally applied opioids vs. placebo and statistically significant increased time to first analgesic (mean difference 153 min, 95% CI: 41-265). When preoperative inflammation was reported (five studies), peripherally applied opioids significantly improved postoperative analgesia. CONCLUSION: Evidence of a clinically relevant analgesic effect of peripherally applied opioids for acute postoperative pain is lacking. The analgesic effect of peripherally applied opioids may depend on the presence of preoperative inflammation.

Increased risk of antidepressant use in childhood cancer survivors: a Danish population-based cohort study.

AIM: Childhood cancer survivors are at risk of both somatic and mental late effects, but large population-based studies of depression are lacking. METHODS: Risk of antidepressant use was evaluated in a population-based cohort of 5452 Danish children treated for cancer in 1975-2009 by linkage to the National Prescription Drug Database, which worldwide is the oldest nationwide registry of prescription medication. Hazard ratios (HRs) for antidepressant use were estimated in a Cox proportional hazards model stratified on sex, with population comparisons as referents. RESULTS: Overall, childhood cancer survivors were at increased risk of having antidepressants prescribed (HR, 1.4; 95% confidence interval (CI), 1.3-1.5). The excess absolute risk of antidepressant use was 2.5 per 1000 person-years (95% CI, 1.7-3.3), equivalent to an excess of 2.5 survivors for every 100 survivors followed for 10years. Increased HRs of 30-50% were seen for survivors of cancers of all main groups (haematological malignancies, central nervous system (CNS) and solid tumors); the highest risk was among children treated with haematopoietic stem cell transplantation (HR, 1.9; 95% CI, 1.2-3.1). Our data suggested that the risk was most pronounced for children treated in the most recent calendar periods (test for interaction between cancer and calendar periods: P<0.001), especially for survivors of haematological cancers (P=0.007). Interaction analysis of the effect of parental socioeconomic position and psychiatric disease on the association between childhood cancer and antidepressant use indicated no modifying effect. CONCLUSION: Childhood cancer survivors should be followed-up for depression. Our results indicate an increasing need for follow-up especially in survivors treated by more recent, intensive anticancer treatment.

Polymorphisms in the ABCB1 gene and effect on outcome and toxicity in childhood acute lymphoblastic leukemia.

The membrane transporter P-glycoprotein, encoded by the ABCB1 gene, influences the pharmacokinetics of anti-cancer drugs. We hypothesized that variants of ABCB1 affect outcome and toxicity in childhood acute lymphoblastic leukemia (ALL). We studied 522 Danish children with ALL, 93% of all those eligible. Risk of relapse was increased 2.9-fold for patients with the 1199GA variant versus 1199GG (P=0.001), and reduced 61% and 40%, respectively, for patients with the 3435CT or 3435TT variants versus 3435CC (overall P=0.02). The degree of bone marrow toxicity during doxorubicin, vincristine and prednisolone induction therapy was more prominent in patients with 3435TT variant versus 3435CT/3435CC (P=0.01/P<0.0001). We observed more liver toxicity after high-dose methotrexate in patients with 3435CC variant versus 3435CT/TT (P=0.03). In conclusion, there is a statistically significant association between ABCB1 polymorphisms, efficacy and toxicity in the treatment of ALL, and ABCB1 1199G>A may be a new possible predictive marker for outcome in childhood ALL.

Genomic profiling of thousands of candidate polymorphisms predicts risk of relapse in 778 Danish and German childhood acute lymphoblastic leukemia patients.

Childhood acute lymphoblastic leukemia survival approaches 90%. New strategies are needed to identify the 10-15% who evade cure. We applied targeted, sequencing-based genotyping of 25 000 to 34 000 preselected potentially clinically relevant single-nucleotide polymorphisms (SNPs) to identify host genome profiles associated with relapse risk in 352 patients from the Nordic ALL92/2000 protocols and 426 patients from the German Berlin-Frankfurt-Munster (BFM) ALL2000 protocol. Patients were enrolled between 1992 and 2008 (median follow-up: 7.6 years). Eleven cross-validated SNPs were significantly associated with risk of relapse across protocols. SNP and biologic pathway level analyses associated relapse risk with leukemia aggressiveness, glucocorticosteroid pharmacology/response and drug transport/metabolism pathways. Classification and regression tree analysis identified three distinct risk groups defined by end of induction residual leukemia, white blood cell count and variants in myeloperoxidase (MPO), estrogen receptor 1 (ESR1), lamin B1 (LMNB1) and matrix metalloproteinase-7 (MMP7) genes, ATP-binding cassette transporters and glucocorticosteroid transcription regulation pathways. Relapse rates ranged from 4% (95% confidence interval (CI): 1.6-6.3%) for the best group (72% of patients) to 76% (95% CI: 41-90%) for the worst group (5% of patients, P<0.001). Validation of these findings and similar approaches to identify SNPs associated with toxicities may allow future individualized relapse and toxicity risk-based treatments adaptation.

A 10-year follow up of reproductive function in women treated for childhood cancer.

Previously, this study group found that female childhood cancer survivors could be at risk of early cessation of fertility. The aim of the present study was to evaluate reproductive function in the same group of survivors 10 years after the initial study. Of the original cohort of 100, 71 were re-examined. Thirty-six survivors reported regular menstrual cycles. When they were compared with 210 controls, they differed significantly in antral follicle count (AFC) (median 15 versus 18, P=0.047) but not in anti-Müllerian hormone (AMH) (median 13.0 versus 17.8 pmol/l). Survivors cured with minimal gonadotoxic treatment had significantly higher AMH and AFC compared with survivors cured with either potentially gonadotoxic treatment or treatment including alkylating chemotherapy and ovarian irradiation (20.0, 5.8 and <3 pmol/l, P<0.001; and 15, 9 and 2, P=0.03, respectively). Thirty-eight survivors had achieved at least one live birth. Complicated second-trimester abortions (n=4) were observed primarily in survivors cured with radiotherapy affecting pelvic organs. In conclusion, childhood cancer survivors have signs of diminished ovarian reserve. However, if the ovarian function is preserved in the early to mid-twenties, it is likely to persist until the mid-thirties, giving a good chance of childbearing.

Patterns of exposure to infectious diseases and social contacts in early life and risk of brain tumours in children and adolescents: an International Case-Control Study (CEFALO).

BACKGROUND: Infectious diseases and social contacts in early life have been proposed to modulate brain tumour risk during late childhood and adolescence. METHODS: CEFALO is an interview-based case-control study in Denmark, Norway, Sweden and Switzerland, including children and adolescents aged 7-19 years with primary intracranial brain tumours diagnosed between 2004 and 2008 and matched population controls. RESULTS: The study included 352 cases (participation rate: 83%) and 646 controls (71%). There was no association with various measures of social contacts: daycare attendance, number of childhours at daycare, attending baby groups, birth order or living with other children. Cases of glioma and embryonal tumours had more frequent sick days with infections in the first 6 years of life compared with controls. In 7-19 year olds with 4+ monthly sick day, the respective odds ratios were 2.93 (95% confidence interval: 1.57-5.50) and 4.21 (95% confidence interval: 1.24-14.30). INTERPRETATION: There was little support for the hypothesis that social contacts influence childhood and adolescent brain tumour risk. The association between reported sick days due to infections and risk of glioma and embryonal tumour may reflect involvement of immune functions, recall bias or inverse causality and deserve further attention.