Risk of Cancer in Children Conceived by Assisted Reproductive Technology

Medically Assisted Reproduction and Risk of Cancer Among Offspring

Importance

Cancer is a leading cause of death among children worldwide. Treatments used for medically assisted reproduction (MAR) are suspected risk factors because of their potential for epigenetic disturbance and associated congenital malformations.

Objective

To assess the risk of cancer, overall and by cancer type, among children born after MAR compared with children conceived naturally.

Design, Setting, and Participants

For this cohort study, the French National Mother-Child Register (EPI-MERES) was searched for all live births that occurred in France between January 1, 2010, and December 31, 2021 (and followed up until June 30, 2022). The EPI-MERES was built from comprehensive data of the French National Health Data System. Data analysis was performed from December 1, 2021, to June 30, 2023.

Exposure

Use of assisted reproduction technologies (ART), such as fresh embryo transfer (ET) or frozen ET (FET), and artificial insemination (AI).

Main Outcomes and Measures

The risk of cancer was compared, overall and by cancer type, among children born after fresh ET, FET, or AI and children conceived naturally, using Cox proportional hazards regression models adjusted for maternal and child characteristics at birth.

Results

This study included 8 526 306 children with a mean (SD) age of 6.4 (3.4) years; 51.2% were boys, 96.4% were singletons, 12.1% were small for gestational age at birth, and 3.1% had a congenital malformation. There were 260 236 children (3.1%) born after MAR, including 133 965 (1.6%) after fresh ET, 66 165 (0.8%) after FET, and 60 106 (0.7%) after AI. A total of 9256 case patients with cancer were identified over a median follow-up of 6.7 (IQR, 3.7-9.6) years; 165, 57, and 70 were born after fresh ET, FET, and AI, respectively. The overall risk of cancer did not differ between children conceived naturally and those born after fresh ET (hazard ratio [HR], 1.12 [95% CI, 0.96 to 1.31]), FET (HR, 1.02 [95% CI, 0.78 to 1.32]), or AI (HR, 1.09 [95% CI, 0.86 to 1.38]). However, the risk of acute lymphoblastic leukemia was higher among children born after FET (20 case patients; HR 1.61 [95% CI, 1.04 to 2.50]; risk difference [RD], 23.2 [95% CI, 1.5 to 57.0] per million person-years) compared with children conceived naturally. Moreover, among children born between 2010 and 2015, the risk of leukemia was higher among children born after fresh ET (45 case patients; HR, 1.42 [95% CI, 1.06 to 1.92]; adjusted RD, 19.7 [95% CI, 2.8 to 43.2] per million person-years).

Conclusions and Relevance

The findings of this cohort study suggest that children born after FET or fresh ET had an increased risk of leukemia compared with children conceived naturally. This risk, although resulting in a limited number of cases, needs to be monitored in view of the continuous increase in the use of ART.

Children born to subfertile couples, how are they doing? Evidence from research

More than 10 million children have been born with assisted reproductive technology (ART) as we begin to enter the third generation of individuals conceived by ART. Here we summarise key messages from an enlarging body of literature regarding their health. Earlier research had pointed towards increases in perinatal, neonatal and neurological risks, such as preterm birth, low birth weight, congenital malformations and cerebral palsy. Many of these risks have continued to persist in most recent work but have shown reduction. Newer research proposes long-term cardiometabolic and endocrine concerns. Fortunately, most reports conclude there is little or no risk of increased childhood malignancy or abnormal neurodevelopment. Moving forward, new research may benefit from changes in comparator groups and a better understanding of infertility per se in ART, and the confounding role it probably plays in many of the known risk associations, to reliably scan the horizon for health threats for individuals born after ART.

The effect of cisplatin-based chemotherapy on hearing loss (the frequency of >8 kHz) in children with cancer

INTRODUCTION

In this study we investigated the effect of cisplatin-based chemotherapy on hearing loss in children with cancer.

MATERIAL AND METHOD

In this retrospective study, 20 children aged 6 to 17 years with cancer who were treated with cisplatin and had normal results on initial audiometry test were included. The demographic, clinical, and medical information of all children was extracted and recorded. The hearing thresholds were determined for the frequency of >8 kHz by an audiometrist two weeks after receiving the last course of cisplatin. Finally, all data was analyzed.

RESULTS

In this study, 20 children with cancer were included of who 9 were girls (45 %) and 11 were boys (55 %). The patients' mean age at the time of diagnosis was 6.65 years. Results showed that children who received cisplatin ≥70 mg/m2 (P.value = 0.09) and ≥ 7 courses of cisplatin (P.value = 0.01), and a cumulative dose higher than 400 mg/m2 (P.value = 0.02) had higher chance of hearing loss.

CONCLUSION

According to the results it can be concluded that since higher doses caused higher risk of hearing loss and also since lower doses were effective for treatment of the cancer in children therefore to preventing the hearing loss, lower doses of cisplatin are recommended for cancer treatment in children.

Polygenic embryo screening: are there potential maternal and fetal harms?

Polygenic embryo screening (PES) and its derivate the Embryo Health Score (EHS) have generated interest in both infertile and fertile populations due to their potential ability to select embryos with a reduced risk of disease and improved long-term health outcomes. Concerns have been raised regarding the potential harms of IVF itself, including possible epigenetic changes that may affect the health of the offspring in late adulthood, which are not fully captured in the EHS calculation. Knowledge of the potential impacts of the trophectoderm biopsy, which is a key component of the PES procedure, on the offsprings' health is limited by the heterogeneity of the population characteristics used in the published studies. Nonetheless, the literature suggests a possible increased risk of preterm delivery, birth defects and pre-eclampsia after trophectoderm biopsy. Overall, the risks of PES for prenatal and postnatal health remain uncertain, and further research is needed. Counselling patients regarding these risks before considering PES is important, to provide an understanding of the risks and benefits. This review aims to highlight some of these issues, the need for continued investigation in this area, and the importance of informed decision-making in the context of PES.

Rhabdoid tumors in patients conceived following ART: is there an association?

STUDY QUESTION

In children affected by rhabdoid tumors (RT), are there clinical, therapeutic, and/or (epi-)genetic differences between those conceived following ART compared to those conceived without ART?

SUMMARY ANSWER

We detected a significantly elevated female predominance, and a lower median age at diagnosis, of children with RT conceived following ART (RT_ART) as compared to other children with RT.

WHAT IS KNOWN ALREADY

Anecdotal evidence suggests an association of ART with RT.

STUDY DESIGN, SIZE, DURATION

This was a multi-institutional retrospective survey. Children with RT conceived by ART were identified in our EU-RHAB database (n = 11/311 children diagnosed between January 2010 and January 2018) and outside the EU-RHAB database (n = 3) from nine different countries. A population-representative German EU-RHAB control cohort of children with RTs conceived without ART (n = 211) (EU-RHAB control cohort) during the same time period was used as a control cohort for clinical, therapeutic, and survival analyses. The median follow-up time was 11.5 months (range 0-120 months) for children with RT_ART and 18.5 months (range 0-153 months) for the EU-RHAB control cohort.

PARTICIPANTS/MATERIALS, SETTING, METHODS

We analyzed 14 children with RT_ART diagnosed from January 2010 to January 2018. We examined tumors and matching blood samples for SMARCB1 mutations and copy number alterations using FISH, multiplex ligation-dependent probe amplification, and DNA sequencing. DNA methylation profiling of tumor and/or blood samples was performed using DNA methylation arrays and compared to respective control cohorts of similar age (n = 53 tumors of children with RT conceived without ART, and n = 38 blood samples of children with no tumor born small for gestational age).

MAIN RESULTS AND THE ROLE OF CHANCE

The median age at diagnosis of 14 individuals with RT_ART was 9 months (range 0-66 months), significantly lower than the median age of patients with RT (n = 211) in the EU-RHAB control cohort (16 months (range 0-253), P = 0.03). A significant female predominance was observed in the RT_ART cohort (M:F ratio: 2:12 versus 116:95 in EU-RHAB control cohort, P = 0.004). Eight of 14 RT_ART patients were diagnosed with atypical teratoid rhabdoid tumor, three with extracranial, extrarenal malignant rhabdoid tumor, one with rhabdoid tumor of the kidney and two with synchronous tumors. The location of primary tumors did not differ significantly in the EU-RHAB control cohort (P = 0.27). Six of 14 RT_ART patients presented with metastases at diagnosis. Metastatic stage was not significantly different from that within the EU-RHAB control cohort (6/14 vs 88/211, P = 1). The incidence of pathogenic germline variants was five of the 12 tested RT_ART patients and, thus, not significantly different from the EU-RHAB control cohort (5/12 versus 36/183 tested, P = 0.35). The 5-year overall survival (OS) and event free survival (EFS) rates of RT_ART patients were 42.9 ± 13.2% and 21.4 ± 11%, respectively, and thus comparable to the EU-RHAB control cohort (OS 41.1 ± 3.5% and EFS 32.1 ± 3.3). We did not find other clinical, therapeutic, outcome factors distinguishing patients with RT_ART from children with RTs conceived without ART (EU-RHAB control cohort). DNA methylation analyses of 10 tumors (atypical teratoid RT = 6, extracranial, extrarenal malignant RT = 4) and six blood samples from RT_ART patients showed neither evidence of a general DNA methylation difference nor underlying imprinting defects, respectively, when compared to a control group (n = 53 RT samples of patients without ART, P = 0.51, n = 38 blood samples of patients born small for gestational age, P = 0.1205).

LIMITATIONS, REASONS FOR CAUTION

RTs are very rare malignancies and our results are based on a small number of children with RT_ART.

WIDER IMPLICATIONS OF THE FINDINGS

This cohort of patients with RT_ART demonstrated a marked female predominance, and a rather low median age at diagnosis even for RTs. Other clinical, treatment, outcome, and molecular factors did not differ from those conceived without ART (EU-RHAB control cohort) or reported in other series, and there was no evidence for imprinting defects. Long-term survival is achievable even in cases with pathogenic germline variants, metastatic disease at diagnosis, or relapse. The female preponderance among RT_ART patients is not yet understood and needs to be evaluated, ideally in larger international series.

STUDY FUNDING/COMPETING INTEREST(S)

M.C.F. is supported by the 'Deutsche Kinderkrebsstiftung' DKS 2020.10, by the 'Deutsche Forschungsgemeinschaft' DFG FR 1516/4-1 and by the Deutsche Krebshilfe 70113981. R.S. received grant support by Deutsche Krebshilfe 70114040 and for infrastructure by the KinderKrebsInitiative Buchholz/Holm-Seppensen. P.D.J. is supported by the Else-Kroener-Fresenius Stiftung and receives a Max-Eder scholarship from the Deutsche Krebshilfe. M.H. is supported by DFG (HA 3060/8-1) and IZKF Münster (Ha3/017/20). BB is supported by the 'Deutsche Kinderkrebsstiftung' DKS 2020.05. We declare no competing interests.

TRIAL REGISTRATION NUMBER

N/A.

Cancer in children born after frozen-thawed embryo transfer: A cohort study

BACKGROUND

The aim was to investigate whether children born after assisted reproduction technology (ART), particularly after frozen-thawed embryo transfer (FET), are at higher risk of childhood cancer than children born after fresh embryo transfer and spontaneous conception.

METHODS AND FINDINGS

We performed a registry-based cohort study using data from the 4 Nordic countries: Denmark, Finland, Norway, and Sweden. The study included 7,944,248 children, out of whom 171,774 children were born after use of ART (2.2%) and 7,772,474 children were born after spontaneous conception, representing all children born between the years 1994 to 2014 in Denmark, 1990 to 2014 in Finland, 1984 to 2015 in Norway, and 1985 to 2015 in Sweden. Rates for any cancer and specific cancer groups in children born after each conception method were determined by cross-linking national ART registry data with national cancer and health data registries and population registries. We used Cox proportional hazards models to estimate the risk of any cancer, with age as the time scale. After a mean follow-up of 9.9 and 12.5 years, the incidence rate (IR) of cancer before age 18 years was 19.3/100,000 person-years for children born after ART (329 cases) and 16.7/100,000 person-years for children born after spontaneous conception (16,184 cases). Adjusted hazard ratio (aHR) was 1.08, 95% confidence interval (CI) 0.96 to 1.21, p = 0.18. Adjustment was performed for sex, plurality, year of birth, country of birth, maternal age at birth, and parity. Children born after FET had a higher risk of cancer (48 cases; IR 30.1/100,000 person-years) compared to both fresh embryo transfer (IR 18.8/100,000 person-years), aHR 1.59, 95% CI 1.15 to 2.20, p = 0.005, and spontaneous conception, aHR 1.65, 95% CI 1.24 to 2.19, p = 0.001. Adjustment either for macrosomia, birth weight, or major birth defects attenuated the association marginally. Higher risks of epithelial tumors and melanoma after any assisted reproductive method and of leukemia after FET were observed. The main limitation of this study is the small number of children with cancer in the FET group.

CONCLUSIONS

Children born after FET had a higher risk of childhood cancer than children born after fresh embryo transfer and spontaneous conception. The results should be interpreted cautiously based on the small number of children with cancer, but the findings raise concerns considering the increasing use of FET, in particular freeze-all strategies without clear medical indications.

TRIAL REGISTRATION

Trial registration number: ISRCTN 11780826.

Atypical Teratoid Rhabdoid Tumor in a Newborn: Can IVF Be a Risk Factor?

BackgroundIn recent years, with the widespread use of assisted reproductive technologies, questions have arisen regarding the possible relationship between these infertile parents with assisted conception procedures and childhood cancers. Case report: We present a 23-day-old newborn conceived by in vitro fertilization (IVF) with a 53 × 46 × 38 mm intracranial mass detected by magnetic resonance imaging on the 15th postnatal day. The mass, removed on 23rd postnatal day, was an Atypical Teratoid Rhabdoid Tumor (ATRT), WHO grade 4. Conclusions: As far as we know, this is the only neonatally detected ATRT. Further studies are needed to investigate whether there is a causal relationship between IVF and childhood cancers.

Assisted reproductive technology and childhood morbidity: a longitudinal cohort study

OBJECTIVE

To evaluate the association between assisted reproductive technology (ART) and offspring morbidity in the first decade of life.

DESIGN

Longitudinal cohort study.

SETTING

Provincial health registry in Quebec, Canada.

PATIENT(S)

A total of 797,654 singleton children born between 2008 and 2019, followed up to 2020.

INTERVENTION(S)

Retrospective, noninterventional study of any ART procedure vs. no ART.

MAIN OUTCOME MEASURE(S)

Childhood morbidity, including hospitalization for infectious, allergic, malignant, and other diseases, assessed using adjusted Cox proportional hazards regression to estimate hazard ratios (HRs) with 95% confidence intervals (CIs) for the association with ART. We controlled for unmeasured family-level confounders that were shared among siblings through stratified Cox regression. To do so, we restricted the analysis to 10,097 siblings with discordant exposure to ART and compared the risk of outcomes in exposed vs. unexposed siblings.

RESULT(S)

Compared with no ART, ART was associated with 1.23 times the risk of any hospitalization (95% CI 1.19-1.27), 1.25 times the risk of infectious disease hospitalization (95% CI 1.21-1.29), and 1.25 times the risk of allergy hospitalization (95% CI 1.14-1.38). When we used a sibling design to control for shared genetic and environmental confounders, ART was not associated with a greater risk of childhood hospitalization (HR 0.92, 95% CI 0.78-1.08).

CONCLUSION(S)

ART is associated with an elevated risk of hospitalization up to 11 years of age, but discordant sibling analysis suggests that the association may be due to genetic, environmental, or other shared familial confounders.

Maternal Medication Use and Childhood Cancer in Offspring-Systematic Review and Considerations for Researchers

Cancer is an important cause of childhood mortality, yet the etiology is largely unknown. A combination of pre- and postnatal factors is thought to be implicated, including maternal medication use. We aimed to provide: 1) a systematic review of peer-reviewed publications on associations between maternal medication use and childhood cancer, with a focus on study design and methodology; and 2) suggestions for how to increase transparency, limit potential biases, and improve comparability in studies on maternal medication use and childhood cancer. We conducted a systematic search in the PubMed, Embase, Scopus, Cochrane, and Web of Science databases to June 8, 2020. Altogether, 112 studies were identified. The reviewed studies were heterogeneous in study design, exposure, and outcome classification. In 21 studies (19%), the outcome was any childhood cancer. Of the 91 papers that reported on specific types of cancer, 62% did not report the cancer classification system. The most frequently investigated medication groups were sex hormones (46 studies, excluding fertility medications), and antiinfectives (37 studies). Suggestions for strengthening future pharmacoepidemiologic studies on maternal medication use and childhood cancer relate to choice of cancer classification system, exposure windows, and methods for identification of, and control for, potential confounders.

A bespoke data linkage of an IVF clinical quality registry to population health datasets; methods and performance

Introduction

Assisted reproductive technologies (ART), such as in-vitro fertilisation (IVF), have revolutionised the treatment of infertility, with an estimated 8 million babies born worldwide. However, the long-term health outcomes for women and their offspring remain an area of concern. Linking IVF treatment data to long-term health data is the most efficient method for assessing such outcomes.

Objectives

To describe the creation and performance of a bespoke population-based data linkage of an ART clinical quality registry to state-based and national administrative datasets.

Methods

The linked dataset was created by deterministically and probabilistically linking the Australia and New Zealand Assisted Reproduction Database (ANZARD) to New South Wales (NSW) and Australian Capital Territory (ACT) administrative datasets (performed by NSW Centre for Health Record Linkage (CHeReL)) and to national claims datasets (performed by Australian Institute of Health and Welfare (AIHW)). The CHeReL’s Master Linkage Key (MLK) was used as a bridge between ANZARD’s partially identifiable patient data (statistical linkage key) and NSW and ACT administrative datasets. CHeReL then provided personal identifiers to the AIHW to obtain national content data. The results of the linkage were reported, and concordance between births recorded in ANZARD and perinatal data collections (PDCs) was evaluated.

Results

Of the 62,833 women who had ART treatment in NSW or ACT, 60,419 could be linked to the CHeReL MLK (linkage rate: 96.2%). A reconciliation of ANZARD-recorded births among NSW residents found that 94.2% (95% CI: 93.9–94.4%) of births were also recorded in state/territory-based PDCs. A high concordance was found in plurality status and birth outcome ≥99% agreement rate, Cohen’s kappa ranged: 0.78–0.98) between ANZARD and PDCs.

Conclusion

The data linkage resource demonstrates that high linkage rates can be achieved with partially identifiable data and that a population spine, such as the CHeReL’s MLK, can be successfully used as a bridge between clinical registries and administrative datasets.

Etiology of Acute Leukemia: A Review

Simple Summary

Acute leukemias are some of the most common cancers affecting all age groups. Despite a significant improvement made in the treatment of acute leukemias, their cause remains unknown. A number of genetic and environmental factors for the development of acute leukemias have been proposed, but none have been proven. Undoubtedly, genetics have a major role in the development of these diseases. The effects of a variety of environmental factors, occupations and hobbies have been explored. A recent “two-hit” theory” for the development of acute lymphoblastic leukemia has been proposed. This combines genetic factors and exposure to infections for the development of this disease. Several genetic factors are suggested. Most recently, for the infection portion, exposure to a virus containing Aspergillus Flavus has been proposed. This review summarizes what is currently known about the factors that are proposed for the development of acute leukemias.

Abstract

Acute leukemias constitute some of the most common malignant disorders. Despite significant progress made in the treatment of these disorders, their etiology remains unknown. A large and diverse group of genetic and environmental variables have been proposed. The role of a variety of factors, including pre-existing and acquired genetic mutations, exposure to radiation and various chemicals during preconception, pregnancy and throughout life, have been explored. The effects of inherited genetic variations and disorders, pre-existing diseases, infectious agents, hobbies, occupations, prior treatments, and a host of other factors have been proposed, but none is universally applicable to all cases. Variation in the incidence and prognosis based on the age, sex, race, type of the disease, geographic area of residence and other factors are intriguing but remain unexplained. Advances in genomic profiling, including genome-wide gene expression, DNA copy number and single nucleotide polymorphism (SNP) genotype, may shed some light on the role of genetics in these disparities. Separate two-hit hypotheses for the development of acute myeloblastic and lymphoblastic leukemia have been proposed. The latter combines genetics and infection factors resulting in leukemogenesis. A number of pre- and post-natal environmental conditions and exposure to infections, including a mycovirus infected Aspergillus flavus, have been suggested. The exact nature, timing, sequence of the events and mechanisms resulting in the occurrence of leukemia requires further investigations. This review summarizes some of the above factors in acute lymphoblastic and myeloblastic leukemias and the direction for future research on the etiology of these disorders.

Validation of Assisted Reproductive Technology in the Medical Birth Registry of Norway Versus the Norwegian Prescription Database

BACKGROUND

Increasing attention has been given to the long-term effects of assisted reproductive technology (ART). This study assessed the validity and completeness of ART as registered in the Medical Birth Registry of Norway (MBRN) using drug prescription data from the Norwegian Prescription Database (NorPD) as reference.

METHODS

In this nationwide registry validation study, we included all pregnancies recorded in the MBRN between 2005 and 2017. We estimated sensitivity, specificity, and positive and negative predictive value (PPV and NPV) of the MBRN, using data from the NorPD as reference. We obtained the total percentage of ART pregnancies that could be identified (completeness) from both registries using the capture-recapture method. We analyzed subgroups by maternal age, gestational length, mode of ART treatment, health region, and mode of registration of ART (ART institution or birth notification form).

RESULTS

Twenty-three thousand seven hundred eighteen of a total 765,789 pregnancies were registered as ART pregnancies through the MBRN and 20,807 as ART pregnancies through the NorPD. The sensitivity of the MBRN was 85.1% (95% confidence interval [CI] = 84.7, 85.6) and the PPV was 74.7% (74.1-75.2). Sensitivity declined with increasing maternal age: 71.5% (69.4-73.7) in the age group 40-44 years, and 40.7% (22.2-59.3) in the ages above 45 years. Completeness when combining data was 96.2% (96.0-96.5).

CONCLUSIONS

Our analysis shows that, when identifying women pregnant through ART, NorPD data complemented MBRN data to obtain a more complete count of all women giving birth after ART in Norway.

Adnexal torsion in pregnancy after in vitro fertilization: Case report and literature review

RATIONALE

Torsion is the most common gynecologic emergency of the adnexal mass occurring during pregnancy. We report the clinical data of a case of twin pregnancy with adnexal torsion after in vitro fertilization (IVF) and embryo transfer, in which the patient underwent surgery for adnexal detorsion and experienced preterm delivery. One child died as a neonate, and the other child was diagnosed with hematological disease, which, to our knowledge, has not been reported previously. We also performed a systematic literature review to increase knowledge of the need for prompt surgical intervention.

PATIENT CONCERNS

The patient was a 32-year-old pregnant woman, who presented to our center with acute onset of stabbing and non-radiating continuous lower left abdominal pain after urination, of 6 hours duration.

DIAGNOSIS

Physical examination revealed that the lower abdominal tenderness was worse on the left side, and there were no signs of peritonitis. Transvaginal ultrasonographic examination indicated a multiloculated left ovary measuring 12.1 × 7.1 cm with sparse blood flow. The size of the largest cyst was 7.2 × 6.6 cm, the right ovary appeared normal, and two live fetuses were seen.

INTERVENTIONS

laparoscopy was performed 1.5 hours later, which revealed a cystic and multilocular left ovary with a black purplish surface and thin wall. The left ovary and left fallopian tube had undergone 720° torsion (3 rotations), and detorsion was performed laparoscopy.

OUTCOMES

The left adnexa recovered to near normal appearance 20 minutes postoperatively. The patient was discharged from hospital 5 days postsurgery, without complications. Unfortunately, the patient delivered two preterm babies at 30 weeks of gestation.

CONCLUSIONS

We should be alert to the possible risk of adnexal torsion in pregnant women after IVF. Adnexal torsion necessitates prompt surgical intervention, detorsion and preserving ovarian function are the main treatment methods. Furthermore, the possibility of recurrence, and pregnancy outcomes for the patient, as well as newborn health, should be considered.

Early Life Oxidative Stress and Long-Lasting Cardiovascular Effects on Offspring Conceived by Assisted Reproductive Technologies: A Review

Assisted reproductive technology (ART) has rapidly developed and is now widely practised worldwide. Both the characteristics of ART (handling gametes/embryos in vitro) and the infertility backgrounds of ART parents (such as infertility diseases and unfavourable lifestyles or diets) could cause increased oxidative stress (OS) that may exert adverse influences on gametogenesis, fertilisation, and foetation, even causing a long-lasting influence on the offspring. For these reasons, the safety of ART needs to be closely examined. In this review, from an ART safety standpoint, the origins of OS are reviewed, and the long-lasting cardiovascular effects and potential mechanisms of OS on the offspring are discussed.

Risk of cancer in children and young adults conceived by assisted reproductive technology

STUDY QUESTION

Do children conceived by ART have an increased risk of cancer?

SUMMARY ANSWER

Overall, ART-conceived children do not appear to have an increased risk of cancer.

WHAT IS KNOWN ALREADY

Despite the increasing use of ART, i.e. IVF or ICSI worldwide, information about possible long-term health risks for children conceived by these techniques is scarce.

STUDY DESIGN, SIZE, DURATION

A nationwide historical cohort study with prospective follow-up (median 21 years), including all live-born offspring from women treated with subfertility treatments between 1980 and 2001.

PARTICIPANTS/MATERIALS, SETTING, METHODS

All offspring of a nationwide cohort of subfertile women (OMEGA study) treated in one of the 12 Dutch IVF clinics or two fertility clinics. Of 47 690 live-born children, 24 269 were ART-conceived, 13 761 naturally conceived and 9660 were conceived naturally or through fertility drugs, but not by ART. Information on the conception method of each child and potential confounders were collected through the mothers’ questionnaires and medical records. Cancer incidence was ascertained through linkage with The Netherlands Cancer Registry from 1 January 1989 until 1 November 2016. Cancer risk in ART-conceived children was compared with risks in naturally conceived children from subfertile women (hazard ratios [HRs]) and with the general population (standardized incidence ratios [SIRs]).

MAIN RESULTS AND THE ROLE OF CHANCE

The median follow-up was 21 years (interquartile range (IQR): 17–25) and was shorter in ART-conceived children (20 years, IQR: 17–23) compared with naturally conceived children (24 years, IQR: 20–30). In total, 231 cancers were observed. Overall cancer risk was not increased in ART-conceived children, neither compared with naturally conceived children from subfertile women (HR: 1.00, 95% CI 0.72–1.38) nor compared with the general population (SIR = 1.11, 95% CI: 0.90–1.36). From 18 years of age onwards, the HR of cancer in ART-conceived versus naturally conceived individuals was 1.25 (95% CI: 0.73–2.13). Slightly but non-significantly increased risks were observed in children conceived by ICSI or cryopreservation (HR = 1.52, 95% CI: 0.81–2.85; 1.80, 95% CI: 0.65–4.95, respectively). Risks of lymphoblastic leukemia (HR = 2.44, 95% CI: 0.81–7.37) and melanoma (HR = 1.86, 95% CI: 0.66–5.27) were non-significantly increased for ART-conceived compared with naturally conceived children.

LIMITATIONS, REASONS FOR CAUTION

Despite the large size and long follow-up of the cohort, the number of cancers was rather small for subgroup analyses as cancer in children and young adults is rare.

WIDER IMPLICATIONS OF THE FINDINGS

Overall, ART-conceived children do not appear to have an increased cancer risk after a median follow-up of 21 years. This large study provides important results, enabling physicians to better inform couples considering ART about the long-term safety of ART for their children. However, larger studies with prolonged follow-up are needed to investigate cancer risk in adults and in children conceived by ICSI and/or from cryopreserved embryos.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by The Dutch Cancer Society (NKI 2006-3631) which funded the OMEGA-women’s cohort and Children Cancer Free (KIKA;147) which funded the OMEGA-offspring cohort. We declare no competing interests.

Preconception nutraceutical food supplementation can prevent oxidative and epigenetic DNA alterations induced by ovarian stimulation for IVF and increases pregnancy rates

BACKGROUND

It is hypothesized that oxidative and epigenetic alterations to DNA induced by ovarian stimulation for in vitro fertilization (IVF) may be associated with an increased risk of diseases and cancer in the offspring and could possibly be attenuated by preconception food supplementation.

METHODS

In a prospective randomised open-label trial, 62 patients were randomly assigned to either 30 days of preconception treatment with the nutraceutical Fertility woman ® duo (Nutriphyt, Beernem, Belgium) (group 1), this nutraceutical complemented with selenomethionine (group 2), or folic acid only (group 3). Biochemical and epigenetic effects and pregnancy rates were assessed.

RESULTS

In all 3 groups the level of DNA oxidative damage, estimated by the concentration of 8-hydroxy- 2-deoxyguanosine over creatinine in early morning urine, and the concentration of homocysteine in the blood decreased after treatment. In group 2, the degree of methylation of the cancer-associated CpG2 dinucleotide of the human Telomerase Reverse Transcriptase (hTERT) promoter region, assessed by pyrosequence in follicular cells obtained at oocyte pick-up, was 18% lower than that of group 3. The pregnancy rate, including the transfer of fresh and frozen embryos, was significantly higher in group 2 (50%) than in group 3 (6%) with the result in group 1 being intermediate (30%).

CONCLUSION

The results suggest that preconception food supplementation using a specific nutraceutical significantly reduces oxidative and epigenetic DNA changes to follicular cells of women treated by IVF, and may optimize gene expression in the oocytes, thus increasing the pregnancy rate per cycle of ovarian stimulation.

Children Conceived by Assisted Reproductive Technology Prone to Low Birth Weight, Preterm Birth, and Birth Defects: A Cohort Review of More Than 50,000 Live Births During 2011-2017 in Taiwan

Objectives: The use of assisted reproductive technology (ART) has increased rapidly in Taiwan. The purpose of this study is to discuss the risks of low birth weight, preterm birth, and birth defect for children conceived by assisted reproductive technology in Taiwan. Methods: Both National ART report database and National birth reports were obtained from the Health Promotion Administration in the Ministry of Health and Welfare in Taiwan. The cohort included live births (n = 1,405,625) and children conceived by ART (n = 50,988/172,818 cycles) from 2011 to 2017. The prevalence of low birth weight, preterm birth, and birth defect were compared between the ART and natural pregnancy groups. Results: Children conceived by ART displayed a higher rate of low birth weight as compared to those in the natural pregnancy group (p < 0.001), even when analyses were restricted to singleton births (p < 0.001). A higher rate of preterm birth (p < 0.001) was also observed in children conceived by ART even when analyses were restricted to singleton births (p < 0.05). A significant increased rate of birth defects was noted from children conceived by ART (p < 0.05). Conclusions: With the increasing need for and use of ART-conceptions, the likelihood of risks induced or related to Assistant Reproductive Technology (ART) has drawn considerable attention in recent years. Taiwan, as one of the leading countries with outstanding ART performances and modern medical care, the result of the current study suggests that further consideration and tighter regulations and policy are needed with regard to the use of ART.

How I approach hereditary cancer predisposition in a child with cancer

Approximately 10% of all children with cancer are affected by a monogenic cancer predisposition syndrome. This has important implications for both the child and her/his family. The assessment of hereditary cancer predisposition is a challenging task for clinicians and genetic counselors in daily routine. It includes consideration of tumor genetics, specific features of the patient, and the medical/family history. To keep up with the pace of this rapidly evolving and increasingly complex field of genetic susceptibility, we suggest a systematic approach for the evaluation of the child with cancer and her/his family by an interdisciplinary team specialized in hereditary cancer predisposition.

Cancer Risk in Children and Young Adults (Offspring) Born after Medically Assisted Reproduction: A Systematic Review and Meta-Analysis

Many studies have investigated the relationship between medically assisted reproduction (MAR) and health outcomes, particularly cancer, in the offspring. This meta-analysis investigated the association between MAR and childhood cancer. Data sources were PubMed, Scopus, and Web of Science up until June 2018. From the selected studies, we extracted the cancer risk estimates of the exposure of interest (MAR, assisted reproductive technology—ART, and in fitro fertilization—IVF). We conducted the meta-analysis using a random effects model. The outcomes of interest were childhood cancers, classified according to the international classification of childhood cancer (ICCC-3). In our meta-analysis (18 cohort and 15 case-control studies) the overall cancer risk was significantly increased in children conceived by MAR, ART, or IVF. MAR and ART significantly increased the risk for hematological tumors, hepatic tumors, and sarcomas (odds ratio (OR) 1.54; 95% CI 1.18–2.02 and OR 1.92; 95% CI 1.34–2.74, respectively). MAR increased acute myeloid leukemia risk (OR 1.41; 95% CI 1.02–1.95) and ART increased neural cancer risk (OR 1.21; 95% CI 1.01–1.46). Our results suggest an increased risk of cancer in children conceived by MAR. Further studies are needed to investigate the impact of fertility treatments, parental subfertility status, and their association on health outcomes in the offspring.

Intracytoplasmic sperm injection for male infertility and consequences for offspring

Intracytoplasmic sperm injection (ICSI) has become the most commonly used method of fertilization in assisted reproductive technology. The primary reasons for its popularity stem from its effectiveness, the standardization of the procedure, which means that it can easily be incorporated into the routine practice of fertility centres worldwide, and the fact that it can be used to treat virtually all forms of infertility. ICSI is the clear method of choice for overcoming untreatable severe male factor infertility, but its (over)use in other male and non-male factor infertility scenarios is not evidence-based. Despite all efforts to increase ICSI efficacy and safety through the application of advanced sperm retrieval and cryopreservation techniques, as well as methods for selecting sperm with better chromatin integrity, the overall pregnancy rates from infertile men remain suboptimal. Treating the underlying male infertility factor before ICSI seems to be a promising way to improve ICSI outcomes, but data remain limited. Information regarding the health of ICSI offspring has accumulated over the past 25 years, and there are reasons for concern as risks of congenital malformations, epigenetic disorders, chromosomal abnormalities, subfertility, cancer, delayed psychological and neurological development, and impaired cardiometabolic profile have been observed to be greater in infants born as a result of ICSI than in naturally conceived children. However, as subfertility probably influences the risk estimates, it remains to be determined to what extent the observed adverse outcomes are related to parental factors or associated with ICSI.

Transitioning from Infertility-Based (ART 1.0) to Elective (ART 2.0) Use of Assisted Reproductive Technologies and the DOHaD Hypothesis: Do We Need to Change Consenting?

The use of assisted reproductive technologies (ARTs) has increased significantly in recent years. While this is partially due to improved access for infertile patients, another contribution to the growth of ART utilization is represented by individuals without infertility, who electively chose to freeze their gametes and embryos for future use, before ever attempting conception spontaneously. Overall, the safety of ART for parents and children is well described and the risks are modest. However, while long-term health consequences for offspring as postulated by the Developmental Origin of Health and Disease (DOHaD) hypothesis are unknown, numerous animal studies suggest a predisposition for chronic diseases like hypertension and glucose intolerance. In this article, we argue that a key difference exists between infertile patients, who need to use ART as the only means to achieve pregnancy, and (likely) fertile patients who elect to use ART techniques as a family planning option. We believe that these two sets of patients are different and their risks-benefit ratios are different. We propose that while all patients should be aware of the risks, patients planning to utilize ART techniques without a diagnosis of infertility should be encouraged to think critically about the additional risks, particularly the "potential" long-term risks that may be imposed from these elective procedures.

Cancer risk in children born after donor ART

STUDY QUESTION

Do children born after donor ART have an increased risk of developing childhood cancer in comparison to the general population?

SUMMARY ANSWER

This study showed no overall increased risk of childhood cancer in individuals born after donor ART.

WHAT IS KNOWN ALREADY

Most large population-based studies have shown no increase in overall childhood cancer incidence after non-donor ART; however, other studies have suggested small increased risks in specific cancer types, including haematological cancers. Cancer risk specifically in children born after donor ART has not been investigated to date.

STUDY DESIGN, SIZE, DURATION

This retrospective cohort study utilized record linkage to determine the outcome status of all children born in Great Britain (1992-2008) after donor ART. The cohort included 12 137 members who contributed 95 389 person-years of follow-up (average follow-up 7.86 years).

PARTICIPANTS/MATERIALS, SETTING, METHODS

Records of all children born in Great Britain (England, Wales, Scotland) after all forms of donor ART (1992-2008) were linked to the UK National Registry of Childhood Tumours (NRCT) to determine the number who subsequently developed cancer by 15 years of age, by the end of 2008. Rates of overall and type specific cancer (selected a priori) were compared with age, sex and calendar year standardized population-based rates, stratifying for potential mediating/moderating factors including sex, age at diagnosis, birth weight, multiple births, maternal previous live births, assisted conception type and fresh/ cryopreserved cycles.

MAIN RESULTS AND THE ROLE OF CHANCE

In our cohort of 12 137 children born after donor ART (52% male, 55% singleton births), no overall increased risk of cancer was identified. There were 12 cancers detected compared to 14.4 expected (standardized incidence ratio (SIR) 0.83; 95% CI 0.43-1.45; P = 0.50). A small, significant increased risk of hepatoblastoma was found, but the numbers and absolute risks were small (<5 cases observed; SIR 10.28; 95% CI 1.25-37.14; P < 0.05). This increased hepatoblastoma risk was associated with low birthweight.

LIMITATIONS REASONS FOR CAUTION

Although this study includes a large number of children born after donor ART, the rarity of specific diagnostic subgroups of childhood cancer results in few cases and therefore wide CIs for such outcomes. As this is an observational study, it is not possible to adjust for all potential confounders; we have instead used stratification to explore potential moderating and mediating factors, where data were available.

WIDER IMPLICATIONS OF THE FINDINGS

This is the first study to investigate cancer risk in children born after donor ART. Although based on small numbers, results are reassuring for families and clinicians. The small but significant increased risk of hepatoblastoma detected was associated with low birthweight, a known risk factor for this tumour type. It should be emphasized that the absolute risks are very small. However, on-going investigation with a longer follow-up is needed.

STUDY FUNDING/COMPETING INTEREST(S)

This work was funded by Cancer Research UK (C36038/A12535) and the National Institute for Health Research (405526) and supported by the National Institute for Health Research Biomedical Research Centre at Great Ormond Street Hospital for Children NHS Foundation Trust and University College London. The work of the Childhood Cancer Research Group (CCRG) was supported by the charity CHILDREN with CANCER UK, the National Cancer Intelligence Network, the Scottish Government and the Department of Health for England and Wales. There are no competing interests.

TRIAL REGISTRATION NUMBER

N/A.

Cancer risk among children conceived by fertility treatment

Prior studies on the association between fertility treatment and childhood cancer risk have generated inconsistent results. We performed a systematic review and meta-analysis of observation studies to summarize the evidence regarding the relation of fertility treatment with childhood cancer risk. A systematic literature search of several databases was conducted through April 2018 to identify relevant studies. The outcomes of interest included overall cancer, haematological malignancies, neural tumours, other solid tumours, and eight specific cancers. The overall risk estimates and corresponding 95% confidence intervals (CIs) were pooled using random-effects meta-analysis. Sixteen cohort and thirteen case-control studies were included. Results showed that children conceived by fertility treatment had significantly higher risk for developing overall cancer (relative risk [RR]: 1.16, 95% CI: 1.01, 1.32), haematological malignancies (RR: 1.39, 95% CI: 1.21, 1.60) and other solid tumours (RR: 1.57, 95% CI: 1.14, 2.16). For specific cancers, fertility treatment was associated with a significantly increased risk of leukaemia (RR: 1.31, 95% CI: 1.09, 1.57) and hepatic tumours (RR: 2.26, 95% CI: 1.32, 3.85). Sensitivity analysis validated evidence of the robustness of the findings. The results may demonstrate a possible association between fertility treatment and an increased risk of cancer among the offspring. However, the findings cannot say whether this increased risk is due to the subfertility itself or to the fertility treatment. Further research is needed to address the underlying mechanisms.

Correction to: Assisted reproductive technologies (ART) and childhood cancer: is the risk real?

The original version of this article unfortunately contained a mistake in the 1st sentence of the 1st paragraph in page 2.

DNA methylation signatures in cord blood of ICSI children

STUDY QUESTION

Does ICSI induce specific DNA methylation changes in the resulting offspring?

SUMMARY ANSWER

Although several thousand analyzed CpG sites (throughout the genome) displayed significant between-group methylation differences, both ICSI and spontaneously conceived children varied within the normal range of methylation variation.

WHAT IS KNOWN ALREADY

Children conceived by ART have increased risks for medical problems at birth and to the extent of present knowledge also in later life (i.e. impaired metabolic and cardiovascular functions). One plausible mechanism mediating these ART effects are epigenetic changes originating in the germ cells and/or early embryos and persisting during further development.

STUDY DESIGN, SIZE, DURATION

We compared the cord blood methylomes and candidate gene methylation patterns of newborns conceived through ICSI or spontaneously.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Umbilical cord bloods were obtained from healthy newborn singletons conceived spontaneously (53 samples), through ICSI (89) or IVF (34). Bisulfite-converted DNA samples of 48 ICSI and 46 control pregnancies were used for genome-wide analyses with Illumina's 450K methylation arrays. Candidate genes from the methylation screen were analyzed in all three groups by bisulfite pyrosequencing.

MAIN RESULTS AND THE ROLE OF CHANCE

Altogether, 4730 (0.11%) of 428 227 analyzed CpG sites exhibited significant between-group methylation differences, but all with small (β < 10%) or very small (β < 1%) effect size. ICSI children showed a significantly decreased DNA methylation age at birth, lagging approximately half a week behind the controls. ART-susceptible CpGs were enriched in CpG islands with low methylation values (0-20%) and in imprinting control regions (ICRs). Eighteen promoter regions (six in microRNA and SNORD RNA genes), four CpG islands (three in genes including one long non-coding RNA), and two ICRs contained multiple significant sites. Three differentially methylated regions were studied in more detail by bisulfite pyrosequencing. ATG4C and SNORD114-9 could be validated in an independent ICSI group, following adjustment for maternal age and other confounding factors. ATG4C was also significant in the IVF group.

LARGE SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

The observed epigenetic effects are small and there are numerous potential confounding factors such as parental age and infertility. Although our study meets current standards for epigenetic screens, sample size is still two orders of magnitude below that of genome-wide association studies.

WIDER IMPLICATIONS OF THE FINDINGS

Our study suggests an impact of ICSI on the offspring's epigenome(s), which may contribute to phenotypic variation and disease susceptibility in ART children. Epigenetic regulation of gene expression by different classes of non-coding RNAs may be a key mechanism for developmental programming through ART.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by a research grant (no. 692185) from the European Union (ERA of ART). There are no competing interests.

Parental age and childhood cancer risk: A Danish population-based registry study

BACKGROUND

Though the association between parental age at child's birth and the risk of childhood cancer has been previously investigated, the evidence to date is inconclusive and scarce for rarer cancer types.

METHODS

Cancer cases (N=5,856) were selected from all children born from 1968 to 2014 and diagnosed from 1968 to 2015 in Denmark at less than 16 years of age listed in the nationwide Danish Cancer Registry. Cases were individually matched to controls (1:100) on sex and year of birth with a total of 585,594 controls randomly sampled from all live births in Denmark from the Danish Central Population Registry. Parental age at child's birth was extracted from the Central Population Registry. Conditional logistic regression models were used to estimate odds ratios for the association between parental age at child's birth and childhood cancer risk. Parental age was modeled as both categorical (referent group, parents aged 25-29) and continuous per 5-year increase in age.

RESULTS

Offspring of older mothers were at an increased risk of acute lymphoblastic leukemia [OR=1.10, 95% CI: (1.02, 1.19) per 5-year increase in age]. Older maternal age (40+) increased the risk of non-Hodgkin lymphoma [OR=1.96, 95%CI: (1.12, 3.43)]. The risk of Wilms' tumor also appeared elevated with older paternal age [OR=1.11, 95% CI: (0.97, 1.28) per 5-year increment in age].

CONCLUSION

Older parental age was a risk factor for various childhood cancers in Danish children. Further investigation of the biological and social factors that may be contributing to these associations is warranted.

Spatial clustering of childhood leukaemia with the integration of the Paediatric Environmental History

BACKGROUND

Leukaemia remains the most common type of paediatric cancer and its aetiology remains unknown, but considered to be multifactorial. It is suggested that the initiation in utero by relevant exposures and/or inherited genetic variants and, other promotional postnatal exposures are probably required to develop leukaemia. This study aimed to map the incidence and analyse possible clusters in the geographical distribution of childhood acute leukaemia during the critical periods and to evaluate the factors that may be involved in the aetiology by conducting community and individual risk assessments.

MATERIALS AND METHODS

We analysed all incident cases of acute childhood leukaemia (<15 years) diagnosed in a Spanish region during the period 1998-2013. At diagnosis, the addresses during pregnancy, early childhood and diagnosis were collected and codified to analyse the spatial distribution of acute leukaemia. Scan statistical test methodology was used for the identification of high-incidence spatial clusters. Once identified, individual and community risk assessments were conducted using the Paediatric Environmental History.

RESULTS

A total of 158 cases of acute leukaemia were analysed. The crude rate for the period was 42.7 cases per million children. Among subtypes, acute lymphoblastic leukaemia had the highest incidence (31.9 per million children). A spatial cluster of acute lymphoblastic leukaemia was detected using the pregnancy address (p<0.05). The most common environmental risk factors related with the aetiology of acute lymphoblastic leukaemia, identified by the Paediatric Environmental History were: prenatal exposure to tobacco (75%) and alcohol (50%); residential and community exposure to pesticides (62.5%); prenatal or neonatal ionizing radiation (42.8%); and parental workplace exposure (37.5%) CONCLUSIONS: Our study suggests that environmental exposures in utero may be important in the development of childhood leukaemia. Due to the presence of high-incidence clusters using pregnancy address, it is necessary to introduce this address into the childhood cancer registers. The Paediatric Environmental History which includes pregnancy address and a careful and comprehensive evaluation of the environmental exposures will allow us to build the knowledge of the causes of childhood leukaemia.

Literature review on cancer risk in children born after fertility treatment suggests increased risk of haematological cancers

Medically assisted fertility treatment, including assisted reproductive technology (ART), is increasingly being used and the subsequent child health outcomes are of interest. Some studies have suggested an elevated risk of somatic morbidity, while others have reported an elevated cancer risk. This review summarises the literature on fertility treatments and childhood cancer, based on 23 cohort and case-control studies.

CONCLUSION

The findings varied, but reassuring results on overall childhood cancer and fertility treatment were observed. However, some studies suggested an elevated risk of haematological cancers. More large population-based studies are needed, and the growing population of ART children should be monitored.

Fertility treatments and pediatric neoplasms of the offspring: results of a population-based cohort with a median follow-up of 10 years

OBJECTIVE

Studies have questioned the long-term health effects of offspring conceived after fertility treatments.

METHODS

We aimed to evaluate whether an association exists between mode of conception (in vitro fertilization, ovulation induction, or spontaneous pregnancy) and neoplasm risk (both benign and malignant tumors) among the offspring; we observed the offspring for up to 18 years.

STUDY DESIGN

A population-based cohort analysis was performed that compared the risk for neoplasms among children (up to the age of 18 years) based on mode of conception. Neoplasm diagnoses were based on hospital records of the same single tertiary center in the region. All singletons born during from 1991-2013 and discharged alive were included in the study. Offspring with congenital malformations were excluded from the analysis. Kaplan-Meier survival curves were constructed to compare cumulative neoplasms incidence; multivariable survival analyses were used to control for confounders that included gestational age, pregnancy complications, and maternal factors.

RESULTS

During the study period, 242,187 newborn infants met the inclusion criteria: 2603 (1.1%) were conceived after in vitro fertilization; 1721 (0.7%) were conceived after ovulation induction treatments, and 237,863 (98.3%) were conceived spontaneously. During the follow-up period (median, 10.55 years), 1498 neoplasms(0.6%) were diagnosed. Incidence density rate for neoplasms was higher among children conceived either after in vitro fertilization (1.5/1000 person years) or ovulation induction treatments (1.0/1000 person years), as compared with naturally conceived children (0.59/1000 person years; Kaplan-Meier log rank, P<.001). The association between in vitro fertilization and total pediatric neoplasms and the association between any fertility treatments and malignancies remained significant; we controlled for confounders such as gestational diabetes mellitus, hypertensive disorders, preterm birth, and maternal age (adjusted hazard ratio, 2.48; 95% confidence interval, 1.71-3.50; and adjusted hazard ratio, 1.96; 95% confidence interval, 1.14-3.36, for all neoplasms and all malignancies, respectively).

CONCLUSION

Children conceived after fertility treatments are at an increased risk for pediatric neoplasms.

Childhood Cancer Risk in the Siblings and Cousins of Men with Poor Semen Quality

PURPOSE

Poor semen quality is associated with reduced somatic health and increased cancer risk. Infertility and cancer are increasingly being linked by epidemiologists and basic scientists. We sought to identify semen parameters associated with an increased childhood cancer risk in the family members of subfertile men.

MATERIALS AND METHODS

We performed a retrospective cohort study in men from the SHARE (Subfertility Heath and Assisted Reproduction) study who underwent semen analysis between 1994 and 2011. We used fertile population controls from the Utah Population Data Base. Our primary outcome was the risk of any childhood (18 years or younger) cancer in the siblings and cousins of men who underwent semen analysis compared to fertile, age matched controls. Cox proportional hazard regression models were used to test the association between semen quality and childhood cancer incidence.

RESULTS

We selected 10,511 men with complete semen analysis and an equal number of fertile controls. These men had a total of 63,891 siblings and 327,753 cousins. A total of 170 and 958 childhood cancers were identified in siblings and cousins, respectively. The 3 most common cancers diagnosed in siblings were acute lymphoblastic leukemia in 37, brain cancer in 35 and Hodgkin lymphoma in 15. Oligozoospermia was associated with a twofold increased risk of any childhood cancer and a threefold increased risk of acute lymphoblastic leukemia in the siblings of subfertile men compared to fertile controls (HR 2.09, 95% CI 1.18-3.69 vs HR 3.07, 95% CI 1.11-8.46).

CONCLUSIONS

Siblings of men with oligozoospermia are at increased risk for any-site cancer and acute lymphoblastic leukemia. This suggests a shared genetic/epigenetic insult or an environmental exposure that merits further investigation.