Fertility treatment and childhood cancer risk: a systematic meta-analysis

Risk of Cancer in Children Conceived by Assisted Reproductive Technology

BACKGROUND AND OBJECTIVE

An increasing number of children are born after assisted reproductive technology (ART), and monitoring their long-term health effects is of interest. This study compares cancer risk in children conceived by ART to that in children conceived without.

METHODS

The Medical Birth Registry of Norway contains individual information on all children born in Norway (including information of ART conceptions). All children born between 1984 and 2011 constituted the study cohort, and cancer data were obtained from the Cancer Registry of Norway. Follow-up started at date of birth and ended on the date of the first cancer diagnosis, death, emigration, or December 31, 2011. A Cox proportional hazards model was used to calculate hazard ratios (HR) and 95% confidence intervals (CI) of overall cancer risk between children conceived by ART and those not. Cancer risk was also assessed separately for all childhood cancer types.

RESULTS

The study cohort comprised 1 628 658 children, of which 25 782 were conceived by ART. Of the total 4554 cancers, 51 occurred in ART-conceived children. Risk of overall cancer was not significantly elevated (HR 1.21; 95% CI 0.90-1.63). However, increased risk of leukemia was observed for children conceived by ART compared with those who were not (HR 1.67; 95% CI 1.02-2.73). Elevated risk of Hodgkin's lymphoma was also found for ART-conceived children (HR 3.63; 95% CI 1.12-11.72), although this was based on small numbers.

CONCLUSIONS

This population-based cohort study found elevated risks of leukemia and Hodgkin's lymphoma in children conceived by ART.

A case-control study of sporadic retinoblastoma in relation to maternal health conditions and reproductive factors: a report from the Children's Oncology group

Background

The early age at retinoblastoma occurrence, the most common eye malignancy in childhood, suggests that perinatal factors may contribute to its etiology.

Methods

In a large multicenter study of non-familial retinoblastoma, we conducted structured interviews with the parents of 280 cases and 146 controls to elicit information on health during the perinatal period. We used unconditional logistic regression to assess associations between retinoblastoma and parental fertility treatment, birth control use in the year prior to pregnancy, maternal health conditions and the use of prescription medications during pregnancy, and whether mothers breastfed the index child.

Results

Bilateral retinoblastoma was related to maternal underweight (body mass index <18.5) prior to pregnancy [Odds Ratio (OR) = 4.5, 95 % confidence interval (CI) 1.0, 20]. With regards to unilateral retinoblastoma, we observed a negative association with the use of condoms in the year prior to pregnancy (OR = 0.4, CI 0.2, 0.9), and a trend towards a positive association with maternal diabetes (OR = 2.2, CI 0.8, 6.6).

Conclusions

Results from our study suggest a role for several maternal health and reproductive factors. Given that there are few epidemiologic studies of retinoblastoma, our results require replication in studies which utilize medical record review.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-015-1773-0) contains supplementary material, which is available to authorized users.

Health and disease in children born after assistive reproductive therapies (ART

In vitro fertilisation (IVF) and other assisted reproductive therapies (ART) offer hope to subfertile couples worldwide. At least 5 million ART children have been born to date. Their health is an issue that is increasingly relevant: first, to those children and young adults themselves; second, to couples considering fertility treatment; and third, to the general population as ART has progressed from experimental treatment to routine practice. Many concerns about the potential risks to these children have been voiced with varying degrees of supportive evidence. This article summarises some key long-term data. Current evidence suggests that ART does increase risk of: higher order pregnancy (with its inherent pre- and perinatal risks); prematurity and low birth weight; congenital malformations in particular of the male urogenital system; imprinting disorders. Reassuringly, evidence points away from an increased overall cancer risk or differences in neurodevelopmental outcomes. Many unknowns remain, including future fertility and cardiovascular risks and risk of cerebral palsy.

Assisted reproductive technology and somatic morbidity in childhood: a systematic review

OBJECTIVE

To assess whether children conceived by assisted reproductive technology are at increased risk of somatic morbidity in childhood compared with spontaneously conceived children.

DESIGN

Systematic review.

SETTING

None.

PATIENT(S)

Children conceived by assisted reproductive technology and reference groups of spontaneously conceived children or children from the background population.

INTERVENTION(S)

Medline/Pubmed, Embase, and the Cochrane Library were searched as well as reference lists of the retrieved relevant studies. Only cohort studies and case-control studies were included. All studies were scored using the Newcastle-Ottawa scale to assess study quality and the risk of bias in the individual studies.

MAIN OUTCOME MEASURE(S)

Postneonatal somatic diseases, health care use, chronic illnesses (unspecified), surgery, use of medication, and mortality.

RESULT(S)

Thirty-eight studies were included. Results indicated that children conceived by assisted reproductive technology may be at increased risk of unspecified infectious and parasitic diseases, asthma, genitourinary diseases, epilepsy or convulsions, and longer hospitalizations. However, several results in individual studies were not statistically significant and some inconsistency existed between study results. No differences between groups were found regarding hospital admission, outpatient visits, or use of medication. Results regarding mortality, unspecified cancer, pneumonia, allergy, respiratory, and gastrointestinal diseases were contradictory. When considering only the 13 studies allocated the highest score on the Newcastle-Ottawa scale, similar results were found.

CONCLUSION(S)

Children conceived by assisted reproductive technology may be at increased risk of somatic morbidity in childhood compared with spontaneously conceived children, although some inconsistency exists between study results.

Maternal use of fertility drugs and risk of cancer in children--a nationwide population-based cohort study in Denmark

Large population-based studies are needed to examine the effect of maternal use of fertility drugs on the risk of cancer in children, while taking into account the effect of the underlying infertility. A cohort of 123,322 children born in Denmark between 1964 and 2006 to 68,255 women who had been evaluated for infertility was established. We used a case-cohort design and calculated hazard ratios (HRs) for cancer in childhood (0-19 years) and in young adulthood (20-29 years) associated with maternal use of six groups of fertility drugs (clomiphene, gonadotropins [i.e., human menopausal gonadotropins and follicle-stimulating hormone], gonadotropin-releasing hormone analogs, human chorionic gonadotropins, progesterone and other fertility drugs). We found no statistically significant association between maternal use of fertility drugs and risk for overall cancer in childhood or young adulthood. However, with regard to specific cancers in childhood, our results showed that maternal use of progesterone before childbirth markedly increased the risks of their offspring for acute lymphocytic leukemia (any use: HR, 4.95; 95% CI, 1.69-14.54; ≥ three cycles of use: HR, 9.96; 95% CI, 2.63-37.77) and for sympathetic nervous system tumors (any use: HR, 5.79; 95% CI, 1.23-27.24; ≥ three cycles of use: HR, 8.51; 95% CI, 1.72-42.19). These findings show that maternal use of progesterone may increase the risk for specific cancers in the offspring. Additional large epidemiological studies are urgently needed to confirm our finding.

A meta-analysis of parental smoking and the risk of childhood brain tumors

OBJECTIVE

Previous studies regarding the association between parental smoking and the risk of childhood brain tumors (CBT) have reported inconsistent results. We performed a meta-analysis to summarize evidence on this association and to quantify the potential dose-response relationship.

METHODS

A systematic literature search was conducted in the Medline and Embase databases. The summary relative risks (RRs) with 95% confidence intervals (CIs) were calculated. Dose-response meta-analysis was also performed for studies that reported categorical risk estimates for a series of smoking exposure levels.

RESULTS

A total of 17 studies fulfilled the inclusion criteria. In the meta-analyses, the summary RRs (95% CIs) of CBT for maternal smoking during pregnancy, paternal smoking during pregnancy, maternal smoking before pregnancy, and paternal smoking before pregnancy were 0.96 (0.86-1.07), 1.09 (0.97-1.22), 0.93 (0.85-1.00), and 1.09 (1.00-1.20), respectively. Dose-response meta-analysis also showed no significant association between parental smoking and the risk of CBT.

CONCLUSIONS

Findings from our meta-analysis indicate that parental smoking may not be associated with a risk of CBT.

Cancer in children and young adults born after assisted reproductive technology: a Nordic cohort study from the Committee of Nordic ART and Safety (CoNARTaS)

STUDY QUESTION

Do children and young adults born after assisted reproductive technology (ART) have an increased risk of cancer?

SUMMARY ANSWER

Children born after ART showed no overall increase in the rate of cancer when compared with children born as a result of spontaneous conception.

WHAT IS KNOWN ALREADY

Children born after ART have more adverse perinatal outcomes, i.e. preterm births, low birthweights and birth defects. Previous studies have shown divergent results regarding the risk of cancer among children born after ART.

STUDY DESIGN, SIZE, DURATION

A retrospective Nordic population-based cohort study was performed, comprising all children born after ART in Sweden, Denmark, Finland and Norway between 1982 and 2007. The mean (±standard deviation) follow-up time was 9.5 (4.8) years.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Children born after ART (n = 91 796) were compared with a control group of children born after spontaneous conception. This control group was almost 4-fold the size of the ART group (n = 358 419) and matched for parity, year of birth and country. Data on perinatal outcomes and cancer were obtained from the National Medical Birth Registries, the Cancer Registries, the Patient Registries and the Cause of Death Registries. The cancer diagnoses were divided into 12 main groups. Hazard ratios (HRs) and adjusted HR were calculated. Adjustments were carried out for country, maternal age, parity, sex, gestational age and birth defects.

MAIN RESULTS AND THE ROLE OF CHANCE

There was no significant increase in overall cancer rates among children born after ART when compared with children born after spontaneous conception (adjusted HR 1.08; 95% CI 0.91-1.27). Cancer, of any form, was found among 181 children born after ART (2.0/1000 children, 21.0/100 000 person-years) compared with 638 children born after spontaneous conception (1.8/1000 children, 18.8/100 000 person-years). Leukaemia was the most common type of cancer (n = 278, 0.62/1000 children) but no significantly increased incidence was found among children born after ART. An increased risk was observed for 2 of 12 cancer groups. They were central nervous system tumours (adjusted HR 1.44; 95% CI 1.01-2.05) and malignant epithelial neoplasms (adjusted HR 2.03; 95% CI 1.06-3.89); the absolute risks were 0.46/1000 and 0.15/1000 children, respectively, corresponding to an absolute increased risk of 0.14/1000 and 0.08/1000 children, respectively.

LIMITATIONS, REASONS FOR CAUTION

As this is an observational study, the main limitation is the fact that it is not possible to adjust for all potential confounders. We were not able to control for confounders such as socio-economic status and perinatal factors, such as Apgar score, which other studies have suggested affect cancer rates.

WIDER IMPLICATIONS OF THE FINDINGS

The results of this large population-based cohort study are in agreement with most previously published studies. The main findings are reassuring for couples undergoing ART, children born after ART and clinicians working with ART.

STUDY FUNDING/COMPETING INTERESTS

No conflict of interest was reported. The study was supported by grants from The European Society for Human Reproduction and Embryology (ESHRE), Sahlgrenska University Hospital, Gothenburg, Sweden, the University of Copenhagen, Denmark, the Danish Agency of Science, Technology and Innovation and the Nordic Federation of Societies of Obstetrics and Gynecology (NFOG).

Stress, Depression, and Fetal Attachment in Pregnant Women having Infertility Treatments

PURPOSE

The purpose of this study was to determine the stress, depression, and fetal attachment of pregnant women who underwent infertility treatment, and to identify factors associated with fetal attachment.

METHODS

As a correlation survey design, data were collected from 136 pregnant women who underwent infertility treatment. Data were analyzed using chi2-test, t-test, ANOVA, Pearson correlation coefficients, and stepwise multiple regression.

RESULTS

Stress, depression, and fetal attachment averaged 3.01+/-0.60 (range of scale 1~5), 10.02+/-6.51 (out of a possible 63), and 3.64+/-0.55 (range of scale 1~5), respectively. Level of fetal attachment was higher when mother's age was less than 35, having other children, and having prenatal education experience. Lower score of depression and client's age less than 35 were significant factors affecting fetal attachment.

CONCLUSION

Infertility is a life-affecting trauma for the individual, and personal and social changes due to infertility cause physical and psychological difficulties even after a successful pregnancy with infertility treatment. Therefore, prenatal management programs need to be developed giving consideration to the emotional and physical changes in order to promote physical and psychological stability in the women pregnant following infertility treatment.

New drug development in childhood cancer

PURPOSE OF REVIEW

Future advances in childhood cancer treatment will pivot on developing biology-driven new drug development pathways that build on current knowledge of oncogenic pathways; however, we need to address major barriers to accessing new drugs for clinical evaluation in childhood cancers.

RECENT FINDINGS

Through legislative change, substantial incentives to the pharmaceutical industry to invest in the ultra-rare diseases, such as childhood cancers, have encouraged greater engagement with paediatric oncology drug development consortia. Disappointingly, this has not translated into paediatric-focussed drug development. Adult disease-driven drug development will continue to dominate until biology/target-driven approaches prevail.There are specific challenges to undertaking early drug development trials in children with incurable disease. The balance between risk and benefit for a child participating in trials wherein the chance of clinical benefit is indeterminate has the potential for unrealistic optimism by both physicians and families. Importantly, innovative trial designs that assess safety and maximize information on potential efficacy from small patient numbers are needed.

SUMMARY

International collaboration in early phase trial consortia addresses these challenges. Academic networks concentrating early phase trials expertise and delivery of innovative trial designs will maximize appropriate selection of drugs that can translate into therapeutic advantage when incorporated into standard care.