Are pre- or postnatal diagnostic X-rays a risk factor for childhood cancer? A systematic review

Utility of Postnatal Chest X-Ray in Newborns for the Evaluation of Prenatally Suspected Congenital Pulmonary Airway Malformation: A Single-Center Experience

OBJECTIVE

 The aim of the study is to assess the necessity of chest X-ray (CXR) during the newborn hospitalization for all patients with prenatally suspected congenital pulmonary airway malformation (CPAM).

STUDY DESIGN

 This is a retrospective chart review of all infants delivered with prenatally suspected CPAM at our high-risk delivery hospital from January 2013 through April 2020 (n = 44). Nonparametric tests assessed the association between postnatal CXR findings, prescribed follow-up timeline, and neonatal outcomes.

RESULTS

 Mean follow-up period recommended was 6.4 weeks regardless of CXR findings in the neonatal period (p = 0.81). Additionally, patients who required respiratory support at or after birth were not more likely to have a lesion identified on chest X-ray (odds ratio [OR] = 0.72, 95% confidence interval [CI], 0.18-2.64, p = 0.71).

CONCLUSION

 Neonatal hospital course and future follow-up plan of patients with prenatally suspected CPAM were not altered by information from the CXR obtained in the immediate neonatal period, suggesting that this CXR may not be necessary in the asymptomatic patient.

KEY POINTS

· Immediate postnatal X-ray of prenatally diagnosed CPAM does not alter planned follow-up interval.. · Immediate postnatal X-ray does not alter surgical plan for CPAM.. · Postnatal X-ray is not absolutely required for asymptomatic newborns with CPAM..

Inheritance of paternal lifestyles and exposures through sperm DNA methylation

Many different lifestyle factors and chemicals present in the environment are a threat to the reproductive tracts of humans. The potential for parental preconception exposure to alter gametes and for these alterations to be passed on to offspring and negatively affect embryo growth and development is of concern. The connection between maternal exposures and offspring health is a frequent focus in epidemiological studies, but paternal preconception exposures are much less frequently considered and are also very important determinants of offspring health. Several environmental and lifestyle factors in men have been found to alter sperm epigenetics, which can regulate gene expression during early embryonic development. Epigenetic information is thought to be a mechanism that evolved for organisms to pass on information about their lived experiences to offspring. DNA methylation is a well-studied epigenetic regulator that is sensitive to environmental exposures in somatic cells and sperm. The continuous production of sperm from spermatogonial stem cells throughout a man's adult life and the presence of spermatogonial stem cells outside of the blood-testis barrier makes them susceptible to environmental insults. Furthermore, altered sperm DNA methylation patterns can be maintained throughout development and ultimately result in impairments, which could predispose offspring to disease. Innovations in human stem cell-based spermatogenic models can be used to elucidate the paternal origins of health and disease.

Unnecessary radiation exposure during diagnostic radiography in infants in a neonatal intensive care unit: a retrospective cohort study

Unnecessary radiation exposure (URE) during radiographic examination is an issue among infants in neonatal intensive care units (NICUs). The causes of URE have not been fully explored. This study investigated the incidence and identified the causes of URE in infants during diagnostic radiography in a NICU. This was a retrospective cohort study. We retrieved and analysed requests and radiographs taken at a tertiary NICU between September and November 2018. URE was defined as the rate of discordance between requests and images taken (DisBRI) and unnecessary radiation exposure in irrelevant regions (UREIR) during radiography. We compared the rates of URE between very low-birth-weight (VLBW, birth weight < 1500 g) infants and non-VLBW infants. A total of 306 radiographs from 88 infants were taken. The means ± standard deviations (SDs) of gestational age and birth weight were 35.7 ± 3.6 weeks and 2471 ± 816 g, respectively. Each infant underwent an average of 3.5 radiographs. The DisBRI rate was 1.3% and was mostly related to poor adherence to requests. The UREIR rates in thoraco-abdominal babygrams were 89.6% for the head, 14.8% for the elbows and 18.4% for the knee and were mainly related to improper positioning of and collimation in infants while performing radiography. The UREIR rates for the head, knee and ankle were higher in VLBW infants than in non-VLBW infants (94.6% vs. 85.6%, 27.0% vs. 11.5% and 5.4% vs. 0.7%, respectively, p < 0.05).

CONCLUSIONS

URE during diagnostic radiography is common in sick infants and is mainly related to improper positioning and collimation during examinations. Adherence to protocols when performing radiographic examination or using ultrasonography may be a solution to reduce URE in infants in NICUs.

WHAT IS KNOWN

• The risk of unnecessary radiation exposure (URE) during radiography has been a common and important issue in sick infants in neonatal intensive care units (NICUs). • The new point-of-care ultrasound (POCUS) technique decreases the need for chest films and prevents radiation exposure in neonates.

WHAT IS NEW

• In the NICU, URE is still a common issue in critically ill infants during radiographic examinations. The causes of URE during diagnostic radiography are mainly due to improper positioning and collimation during examinations. • The incidence of URE in irrelevant regions is higher in very low-birth-weight (VLBW) infants than in non-VLBW infants.

Chromosome aberrations among atomic-bomb survivors exposed in utero: updated analysis accounting for revised radiation doses and smoking

A previous study of peripheral blood lymphocyte translocations around age 40 among atomic-bomb survivors exposed in utero revealed no overall association with radiation dose-despite a clear association between translocations and dose among their mothers-but the data suggested an increase at doses below 100 mGy with a definite peak. That analysis of the in utero-exposed survivors did not adjust for their subsequent smoking behavior, an established cause of chromosomal aberrations, or their subsequent exposures to medical irradiation, a potential mediator. In addition, atomic-bomb survivor radiation dose estimates have subsequently been updated and refined. We therefore re-estimated the dose response using the latest DS02R1 dose estimates and adjusting for smoking as well as for city and proximal-distal location at the time of exposure to the atomic bomb. Sex of the survivor, mother's age around the time of conception, and approximate trimester of gestation at the time of exposure were also considered as explanatory variables and modifiers. Precision of the estimated dose response was slightly lower due to greater variability near zero in the updated dose estimates, but there was little change in evidence of a low-dose increase and still no suggestion of an overall increase across the entire dose range. Adjustment for smoking behavior led to a decline in background number of translocations (the dose-response intercept), but smoking did not interact with dose overall (across the entire dose range). Adjustment for medical irradiation did not alter the association between dose and translocation frequency. Sex, mother's age, and trimester were not associated with number of translocations, nor did they interact with dose overall. Interactions with dose in the low-dose range could not be evaluated because of numerical instability.

Lung ultrasonography decreases radiation exposure in newborns with respiratory distress: a retrospective cohort study

Chest X-ray (CXR) is commonly used as a first-line imaging method to determine the cause of respiratory distress in NICUs. The aim of the study was to retrospectively assess the decrease in the number of CXRs performed due to the use of lung ultrasonography on the first day of life for newborns with respiratory distress. Infants who were admitted to the NICU on the first day of life due to respiratory distress were enrolled in this study (ClinicalTrials.gov identifier NCT04722016) and divided into two groups: the study group (n = 104) included patients born between January 2019 and June 2020, and the historical control group (n = 73) included patients born between June 2017 and December 2018. As a first-line technique for lung imaging, only CXR had been used in the historical control group, whereas ultrasound had been preferred in the study group. The radiation dose to the newborns and the number of CXRs performed in the first day of life were compared between the two groups. Significant reductions in the number of CXRs performed and radiation exposure were observed in the study group. The radiation dose decreased from 5.54 to 4.47 µGy per baby when LUS was routinely used. The proportion of patients who underwent CXR decreased from 100 to 71.2%.Conclusion: We observed that using lung ultrasonography as a first-line evaluation method in neonates with respiratory distress decreased both the number of CXRs performed and radiation exposure. What is Known: • Chest X-ray is commonly used as a first line imaging method to diagnose the reason of respiratory distress in NICUs. • Lung ultrasound is a new diagnostic tool for lung imaging. What is New: • With the use of lung ultrasonography, radiation exposure of both newborns and healthcare workers can be reduced. • This retrospective study revealed that most of the babies with respiratory distress were treated without CXR.

Comparison of intracranial injury predictability between machine learning algorithms and the nomogram in pediatric traumatic brain injury

OBJECTIVE

The overuse of head CT examinations has been much discussed, especially those for minor traumatic brain injury (TBI). In the disruptive era, machine learning (ML) is one of the prediction tools that has been used and applied in various fields of neurosurgery. The objective of this study was to compare the predictive performance between ML and a nomogram, which is the other prediction tool for intracranial injury following cranial CT in children with TBI.

METHODS

Data from 964 pediatric patients with TBI were randomly divided into a training data set (75%) for hyperparameter tuning and supervised learning from 14 clinical parameters, while the remaining data (25%) were used for validation purposes. Moreover, a nomogram was developed from the training data set with similar parameters. Therefore, models from various ML algorithms and the nomogram were built and deployed via web-based application.

RESULTS

A random forest classifier (RFC) algorithm established the best performance for predicting intracranial injury following cranial CT of the brain. The area under the receiver operating characteristic curve for the performance of RFC algorithms was 0.80, with 0.34 sensitivity, 0.95 specificity, 0.73 positive predictive value, 0.80 negative predictive value, and 0.79 accuracy.

CONCLUSIONS

The ML algorithms, particularly the RFC, indicated relatively excellent predictive performance that would have the ability to support physicians in balancing the overuse of head CT scans and reducing the treatment costs of pediatric TBI in general practice.

Prenatal X-ray Exposure and the Risk of Developing Pediatric Cancer-A Systematic Review of Risk Markers and a Comparison of International Guidelines

ABSTRACT

Since the first Oxford Survey of Childhood Cancer's results were published, people have become more aware of the risks associated with prenatal exposure from diagnostic x rays. As a result, it has since been the subject of many studies. In this review, the results of recent epidemiological studies are summarized. The current international guidelines for diagnostic x-ray examinations were compared to the review. All epidemiological studies starting from 2007 and all relevant international guidelines were included. Apart from one study that involved rhabdomyosarcoma, no statistically significant associations were found between prenatal exposure to x rays and the development of cancer during 2007-2020. Most of the studies were constrained in their design due to too small a cohort or number of cases, minimal x-ray exposure, and/or data obtained from the exposed mothers instead of medical reports. In one of the studies, computed tomography exposure was also included, and this requires more and longer follow-up in successive studies. Most international guidelines are comparable, provide risk coefficients that are quite conservative, and discourage abdominal examinations of pregnant women.

Effects of Lifestyle and Environmental Factors on the Risk of Acute Myeloid Leukemia: Result of a Hospital-based Case-Control Study

Background: Acute myeloid leukemia (AML) is a common malignancy in adults. A vast variety of environmental and lifestyle factors play a role in AML incidence. This study aimed to assess the factors related to AML.

Study design: A case-control study.

Methods: This case-control study was performed on 137 AML cases during 2018-2021 at Beheshti Hospital in Hamadan, Iran, and 137 gender/age-matched controls. A questionnaire including 12 items was used to obtain information about lifestyle and environmental factors. A univariate and multiple variate logistic regression was used to estimate the odds ratios (OR), and a 95% confidence interval (CI) was used to investigate the relationship between the studied variables and the incidence of AML.

Results: Based on findings, 62 (45.3%) out of the 137 leukemic cases were male and 75 (4.7%) were females. A statistically significant increased risk for AML was found with regard to prior usage of cytotoxic agents (OR: 8.00, 95% CI: 1.01, 63.9, P=0.050), family history of malignancies (OR: 3.62, 95% CI: 1.65, 7.92, P=0.001), exposure to electrical power (OR: 3.22, 95% CI: 1.52, 6.81, P=0.002), and history of mental diseases (OR: 8.50, 95% CI: 3.64, 19.80, P=0.001). It was found that the AML incidence had no association with age, gender, radiation therapy, cigarette smoking, prior chemotherapy, congenital disorders, exposure to chemical agents, history of infectious mononucleosis, exercise, and blood transfusion (P>0.05).

Conclusion: The current results suggested that cytotoxic agents, family history of malignancy, mental disorders, and exposure to electrical power could play a role in AML incidence.

Infantile neuroblastoma and maternal occupational exposure to medical agents

BACKGROUND

Healthcare workers are often exposed to hazardous agents and are at risk for adverse health consequences that affect not only themselves but also their infants. This study aimed to examine whether such occupational exposure increased the risk of childhood cancer in offspring.

METHODS

We used the dataset of the Japan Environment and Children's Study, a nationwide birth cohort involving over 100,000 mother-child pairs. Information was obtained via successive questionnaires that were completed until the child turned 1 year of age. The parents were asked whether they occupationally handled medical agents during pregnancy.

RESULTS

A total of 26 infants developed neoplasms: neuroblastoma, leukemia, and brain tumor. The incidence of neuroblastoma was significantly higher in infants whose mothers were exposed to radiation (3/2142: 140.1 per 100,000 population) than in those who were not (12/90,384: 13.3 per 100,000 population). Multivariable regression analyses revealed a close association between maternal irradiation and the development of neuroblastoma (adjusted incident rate ratio: 10.68 [95% confidence interval: 2.98‒38.27]).

CONCLUSIONS

The present study demonstrated, for the first time, a potential association between maternal occupational exposure and the occurrence of neuroblastoma in offspring. Further studies involving the large pediatric cancer registries are needed to confirm these preliminary results.

IMPACT

Healthcare workers are often exposed to hazardous agents and are at risk for adverse health consequences that affect not only themselves but also their infants. This study examined the association between such occupational exposure and offspring's cancers that developed until the age of 1 year. Maternal exposure to ionizing radiation was associated with infantile neuroblastoma in offspring. Further studies involving the large pediatric cancer registries are needed to confirm these preliminary results.

A review of the types of childhood cancer associated with a medical X-ray examination of the pregnant mother

PURPOSE

For 65 years the interpretation of the statistical association between the risk of cancer in a child and a prior diagnostic X-ray examination of the abdomen of the pregnant mother has been debated. The objections to a direct cause-and-effect explanation of the association vary in their strength, but one of the most notable grounds for controversy is the finding from the first and largest case-control study reporting the association, the Oxford Survey of Childhood Cancers (OSCC), of an almost uniformly raised relative risk (RR) for nearly all of the types of cancer that are most frequent in children. Here we compare the antenatal X-ray associations found in the OSCC for different types of childhood cancer with the results of all other case-control and case-cohort studies appropriately combined in meta-analyses, and we also review the findings of the few cohort studies that have been conducted.

CONCLUSIONS

From the case-control/case-cohort studies other than the OSCC there are consistent and clear elevations of risk for all types of childhood cancer combined, all leukemia, and all cancers except leukemia combined. This compatibility of the findings of the OSCC with those of the combined other studies is less clear, or effectively absent, when some categories containing smaller numbers of incident cases/deaths are considered, but lack of precision of risk estimates due to sparse data presents inferential challenges, although there is a consistent absence of an association for bone tumors. Further, more recent studies almost certainly address lower intrauterine doses, with an anticipated decrease in estimated risks, which could be misleading when comparisons involve a limited number of studies that are mainly from later years, and a similar problem arises when having to employ all types of antenatal X-ray exposures for a study because data for abdominal exposures are absent. The problem of low statistical power is greater for cohort studies, and this, together with other shortcomings identified in the studies, limits the interpretational value of results. The findings of non-medical intrauterine exposure studies are constrained by sparse data and make a limited contribution to an understanding of the association. Certain aspects of the various studies require a need for caution in interpretation, but overall, the appropriate combination of all case-control/case-cohort studies other than the OSCC lends support to the inference that low-level exposure to radiation in utero proportionally increases the risk of the typical cancers of childhood to around the same level.

Early life ionizing radiation exposure and cancer risks: systematic review and meta-analysis

BACKGROUND

Ionizing radiation use for medical diagnostic purposes has substantially increased over the last three decades. Moderate to high doses of radiation are well established causes of cancer, especially for exposure at young ages. However, cancer risk from low-dose medical imaging is debated.

OBJECTIVE

To review the literature on cancer risks associated with prenatal and postnatal medical diagnostic ionizing radiation exposure among children and to assess this risk through a meta-analysis.

MATERIALS AND METHODS

A literature search of five electronic databases supplemented by a hand search was performed to retrieve relevant epidemiological studies published from 2000 to 2019, including patients younger than 22 years of age exposed to medical imaging ionizing radiation. Pooled odds ratio (OR_pooled) and pooled excess relative risk (ERR_pooled) representing the excess of risk per unit of organ dose were estimated with a random effect model.

RESULTS

Twenty-four studies were included. For prenatal exposure (radiographs or CT), no significant increased risk was reported for all cancers, leukemia and brain tumors. For postnatal exposure, increased risk was observed only for CT, mostly for leukemia (ERR_pooled=26.9 Gy^-1; 95% confidence interval [CI]: 2.7-57.1) and brain tumors (ERR_pooled=9.1 Gy^-1; 95% CI: 5.2-13.1).

CONCLUSION

CT exposure in childhood appears to be associated with increased risk of cancer while no significant association was observed with diagnostic radiographs.

Long-term follow-up after fetal radiation exposure during endoscopic retrograde cholangiopancreatography

Background and study aims  The main concern about endoscopic retrograde cholangiopancreatography (ERCP) during pregnancy is the risk of radiation exposure to the fetus. The potential exists not only in the short-term, but also in the long-term and includes growth and development problems and the possibility of childhood cancer. Little is known about the long-term effects of fetal radiation exposure at the time of ERCP. The aim of the study was to report the long-term outcome of babies born after radiation exposure to mothers who underwent ERCP during pregnancy. Patients and methods  This was a single-center retrospective cohort study. We included 24 consecutive pregnant patients who underwent ERCP due to choledocholithiasis and their children, between June 1997 and June 2015. All patients and their babies were followed up until birth to assess their short-term outcome. To assess long-term outcomes, from September 2014 to September 2015, a comprehensive medical interview was conducted with the mothers and their children. We also evaluated medical records, lab tests, school report cards, and the families completed a questionnaire inquiring about perceived health status of the children. Results  Fifteen patients had full-term pregnancies. One patient had a preterm delivery (32 weeks) due to preeclampsia. There were no cases of miscarriage, stillbirth or fetal malformations. Long-term follow-up was performed at a mean age of 11.08 years (range 1-18) for the children, with no developmental delays, poor school performance, or malignancies found. Conclusions  Long-term outcome in children born after radiation exposure during ERCP was unremarkable.

5 Reasons Why Scoliosis X-Rays Are Not Harmful

Radiographic imaging for scoliosis screening, diagnosis, treatment, and management is the gold standard assessment tool. Scoliosis patients receive many repeat radiographs, typically 10-25 and as many as 40-50, equating to a maximum 50 mGy of cumulative exposure. It is argued this amount of radiation exposure is not carcinogenic to scoliosis patients for 5 main reasons: 1. Estimated theoretical cumulative effective doses remain below the carcinogenic dose threshold; 2. Scoliosis patient x-rays are delivered in serial exposures and therefore, mitigate any potential cumulative effect; 3. Linear no-threshold cancer risk estimates from scoliosis patient cohorts are flawed due to faulty science; 4. Standardized incidence/mortality ratios demonstrating increased cancers from aged scoliosis cohorts are confounded by the effects of the disease entity itself making it impossible to claim cause and effect resulting from low-dose radiation exposures from spinal imaging; 5. Children are not more susceptible to radiation damage than adults. Radiophobia concerns from patients, parents, and doctors over repeat imaging for scoliosis treatment and management is not justified; it adds unnecessary anxiety to the patient (and their parents) and interferes with optimal medical management. X-rays taken in the evidence-based management of scoliosis should be taken without hesitation or concern about negligible radiation exposures.

Diagnostic X-Ray Exposure and Thyroid Cancer Risk: Systematic Review and Meta-Analysis

BACKGROUND

Radiation exposure is a well-known risk factor for thyroid cancer. However, the specific effects of diagnostic radiation exposure on thyroid cancer risk are controversial. The purpose of this study was to perform a systematic review and meta-analysis to assess the effects of diagnostic radiation exposure on thyroid cancer risk.

METHODS

The PubMed and EMBASE databases were searched to identify eligible studies. Summary odds ratio (OR) estimates and confidence intervals (CIs) were used to compute the risk of thyroid cancer using fixed- and random-effects models. Subgroup and sensitivity analyses were performed to evaluate the potential heterogeneity.

RESULTS

Nine studies from 12 publications were included in the meta-analysis. Overall exposure to diagnostic radiation exposure was associated with a significantly increased thyroid cancer risk (OR = 1.52 [CI 1.13-2.04]). The subgroup and sensitivity analyses revealed similar results. By type of exposure, exposure to computed tomography scans (OR = 1.46 [CI 1.27-1.68]) or dental x-rays (OR = 1.69 [CI 1.17-2.44]) were associated with an increased thyroid cancer risk. Head and neck (OR = 1.31 [CI 1.02-1.69]) and chest (OR = 1.71 [CI 1.09-2.69]) exposure to diagnostic radiation was associated with an increased thyroid cancer risk.

CONCLUSIONS

The results of this meta-analysis indicate that diagnostic radiation exposure is associated with an increased thyroid cancer risk. Therefore, to the extent that it will not compromise the information being sought, radiation exposure to the thyroid should be minimized during diagnostic examinations.

Neonatal respiratory distress syndrome: Chest X-ray or lung ultrasound? A systematic review

BACKGROUND AND AIM

Neonatal respiratory distress syndrome is a leading cause of morbidity in preterm new-born babies (<37 weeks gestation age). The current diagnostic reference standard includes clinical testing and chest radiography with associated exposure to ionising radiation. The aim of this review was to compare the diagnostic accuracy of lung ultrasound against the reference standard in symptomatic neonates of ≤42 weeks gestation age.

METHODS

A systematic search of literature published between 1990 and 2016 identified 803 potentially relevant studies. Six studies met the review inclusion criteria and were retrieved for analysis. Quality assessment was performed before data extraction and meta-analysis.

RESULTS

Four prospective cohort studies and two case control studies included 480 neonates. All studies were of moderate methodological quality although heterogeneity was evident across the studies. The pooled sensitivity and specificity of lung ultrasound were 97% (95% confidence interval [CI] 94-99%) and 91% (CI: 86-95%) respectively. False positive diagnoses were made in 16 cases due to pneumonia (n = 8), transient tachypnoea (n = 3), pneumothorax (n = 1) and meconium aspiration syndrome (n = 1); the diagnoses of the remaining three false positive results were not specified. False negatives diagnoses occurred in nine cases, only two were specified as air-leak syndromes.

CONCLUSIONS

Lung ultrasound was highly sensitive for the detection of neonatal respiratory distress syndrome although there is potential to miss co-morbid air-leak syndromes. Further research into lung ultrasound diagnostic accuracy for neonatal air-leak syndrome and economic modelling for service integration is required before lung ultrasound can replace chest radiography as the imaging component of the reference standard.

In utero exposure to radiation and haematological malignancies: pooled analysis of Southern Urals cohorts

BACKGROUND

It is scientifically uncertain whether in utero exposure to low-dose ionising radiation increases the lifetime risk of haematological malignancies.

METHODS

We pooled two cohorts from the Southern Urals comprising offspring of female workers of a large nuclear facility (the Mayak Production Association) and of women living in areas along the Techa River contaminated by nuclear accidents/waste from the same facility, with detailed dosimetry.

RESULTS

The combined cohort totalled 19 536 subjects with 700 504 person-years at risk over the period of incidence follow-up, and slightly more over the period of mortality follow-up, yielding 58 incident cases and 36 deaths up to age 61 years. Risk was increased in subjects who received in utero doses of ⩾80 mGy (excess relative risk (ERR): 1.27; 95% confidence interval (CI): -0.20 to 4.71), and the risk increased consistently per 100 mGy of continuous exposure in utero (ERR: 0.77; CI: 0.02 to 2.56). No association was apparent in mortality-based analyses. Results for leukaemia and lymphoma were similar. A very weak positive association was observed between incidence and postnatal exposure.

CONCLUSIONS

In summary, the results suggest a positive association between in utero exposure to ionising radiation and risk of haematological malignancies, but the small number of outcomes and inconsistent incidence and mortality findings preclude firm conclusions.

Prenatal and Postnatal Medical Conditions and the Risk of Brain Tumors in Children and Adolescents: An International Multicenter Case-Control Study

BACKGROUND

Previous studies have evaluated the effect of medical diagnostic radiation on brain tumors. Recent cohort studies have reported an increased risk associated with exposure to head CT scans.

METHODS

Information regarding medical conditions, including prenatal and postnatal exposure to medical diagnostic radiation, was obtained from CEFALO, a multicenter case-control study performed in Denmark, Norway, Sweden, and Switzerland through face-to-face interview. Eligible cases of childhood and adolescent brain tumors (CABT) were ages 7 to 19 years, diagnosed between January 1, 2004 and August 31, 2008, and living in the participating countries (n = 352). The cases were matched by age, sex, and region to 646 population-based controls.

RESULTS

Prenatal exposure to medical diagnostic radiation and postnatal exposure to X-rays were not associated with CABTs. A higher risk estimate of CABTs, although not statistically significant, was found for exposure to head CT scan (OR, 1.86; 95% confidence interval, 0.82-4.22). The associations with head injury, febrile seizure, fever in the first 12 weeks, and general anesthesia were close to unity.

CONCLUSIONS

Prenatal or postnatal medical conditions, including medical diagnostic radiation, were not associated with CABTs. On the basis of small numbers of exposed children, we observed a nonsignificant increased risk for CT scans of the head.

IMPACT

We have presented additional evidence, suggesting that exposure to head CT scan may be associated with the occurrence of CABTs. Cancer Epidemiol Biomarkers Prev; 26(1); 110-5. ©2016 AACR.

Risk of Hematologic Malignancies in the Offspring of Female Workers of the Mayak Nuclear Facility in the Southern Urals, Russian Federation

Long-term effects of in utero exposure to ionizing radiation remain poorly quantified in humans. In this study, the risk of hematologic malignancies was investigated in offspring of female workers of the Mayak Production Association, a large Russian nuclear facility. Excess relative risks (ERR) for exposure to gamma radiation and plutonium were estimated in a cohort of 8,466 offspring who were born between January 1, 1948 and December 31, 1988 and followed until 2009. An unstable linear ERR of 1.12 (95% CI 0.11-3.44) per 100 mGy gamma exposure in utero was estimated based on 32 incident hematologic malignancies in 277,002 person-years under risk. The ERR was increased in the dose category 20-79 mGy gamma exposure in utero (1.75, 95% CI 0.04; 5.63), while the other dose categories showed decreased or unstable estimates. Leukemia showed an ERR of 1.76 (95% CI 0.01-8.33) per 100 mGy based on 13 cases. There was no consistent association with plutonium exposure. While an increased risk of hematologic malignancies after gamma exposure in utero was suggested, the small numbers prevented more definitive conclusions.

Is There a Need for Repeat Radiologic Examination of Children with Esophageal Coin Foreign Body?

Objectives To determine factors associated with the passage of coins. To determine the need for repeat preoperative chest x-ray (CXR) for esophageal coin foreign body. Setting Academic tertiary care center. Design Case series with chart review. Subjects and Methods Patient information was retrieved from an Institutional Review Board-approved database. We identified 1359 children with esophageal coin foreign bodies from 2001 to 2013. Patients with both initial diagnostic and immediate preoperative CXR were included. Results A total of 406 patients met inclusion criteria. The average age was 47 months (range, 1.8-194 months). On preoperative CXR, the position changed in 29 patients (7%). Age, type of coin, and location of coin were all statistically significant factors affecting the passage of the coin ( P < .0001). Coins in the distal esophagus were 9.3 times more likely to pass than coins in the proximal esophagus. The longer the object was in the esophagus, the less likely it was to pass. Conclusions This study characterizes when esophageal coins may pass. Age, type of coin, location of coin at initial x-ray, and length of time are all important considerations to determine if the coin will pass. This information may be used to counsel families about the likelihood of coins to pass and whether repeat x-ray is necessary prior to surgical removal. Additionally, it may be more cost-effective to obtain repeat films in select patients and prevent those from going to the operating theater who are more likely to pass the coin spontaneously.

Risk of solid cancer in the offspring of female workers of the Mayak nuclear facility in the Southern Urals, Russian Federation

Studies of cancer risk following in utero exposure to ionizing radiation are limited in number, particularly for adult-onset cancers, and the evidence is unclear. In the present study, the risk of solid cancer incidence following in utero radiation exposure is examined among 8466 offspring of female nuclear workers at one of the largest nuclear facilities (Mayak Production Association) in the Russian Federation. Poisson regression methods were used to estimate excess relative risks (ERRs) per Gray (Gy). Mother's uterine gamma dose served as a surrogate for fetal gamma dose. During 277,002 person-years of follow-up (1948-2009), there were 177 first primary solid cancers excluding non-melanoma skin cancers. Estimated in utero gamma and plutonium doses exceeded zero for 41 and 23 % of offspring, respectively. Of the 177 solid cancers, 66 occurred among individuals with some in utero exposure to gamma radiation and 53 among those with estimated plutonium exposures. There was no indication of a statistically significantly increased risk of solid cancer incidence from in utero gamma exposure (linear ERR/Gy -1.0; upper 95 % confidence limit 0.5). This result was unchanged after accounting for subsequent occupational exposure. Plutonium doses were estimated but were too low to obtain meaningful risk estimates. Thus, in this cohort in utero radiation exposure was not associated with solid cancer risk. This is consistent with an earlier report of mortality in the cohort, but is based on twice as many cases and less susceptible to biases inherent in mortality analyses. Given the relatively young age of the cohort with respect to cancer, continued follow-up should be done as the number of cancer cases increases.

Chemotherapeutic treatment of colorectal cancer in pregnancy: case report

INTRODUCTION

Colon cancer in pregnancy is uncommon. Only a small number of case reports have been published in the literature on the use of chemotherapeutic drugs during pregnancy. Reports of such cases assist clinicians in further investigating the use of chemotherapy in pregnancy.

CASE PRESENTATION

FOLFOX-6 was administered to a pregnant, 33-year-old Saudi woman with metastatic colon cancer from 22 to 30 weeks of gestation. Her cancer was diagnosed during her pregnancy. She tolerated the chemotherapy well and delivered a full-term baby girl with no obvious harm, and normal development was documented at her 2-year follow-up examination.

CONCLUSION

Colon cancer during pregnancy is not easily detected and is difficult to manage. A detailed history and high clinical suspicion are needed in patients who present with symptoms and signs suggestive of malignancy. A multidisciplinary approach with patient involvement is needed to decrease morbidity and mortality caused by both treatment and the cancer in the mother and to limit side effects for the fetus. Further data and long-term follow-up are needed to better understand the potential long-term side effects of chemotherapeutic drugs on offspring.

Infrared thermography is useful for ruling out fractures in paediatric emergencies

Musculoskeletal injuries are a leading cause of paediatric injuries and emergency department visits in Western countries. Diagnosis usually involves radiography, but this exposes children without fractures to unnecessary ionising radiation. We explored whether infrared thermography could provide a viable alternative in trauma cases. We compared radiography and thermal images of 133 children who had been diagnosed with a trauma injury in the emergency unit of a Spanish hospital. As well as the thermal variables in the literature, we introduced a new quantifier variable, the size of the lesion. Decision tree models were built to assess the technique's accuracy in diagnosing whether a bone had been fractured or not. Infrared thermography had a sensitivity of 0.91, a specificity of 0.88 and a negative predictive value of 0.95. The new lesion size variable introduced appeared to be of main importance to the discriminatory power of the method.

CONCLUSION

The high negative predictive value of infrared thermography suggests that it is a promising method for ruling out fractures.

Are Risks From Medical Imaging Still too Small to Be Observed or Nonexistent?

Several radiation-related professional societies have concluded that carcinogenic risks associated with doses below 50-100 mSv are either too small to be detected, or are nonexistent. This is especially important in the context of doses from medical imaging. Radiation exposure to the public from medical imaging procedures is rising around the world, primarily due to increased utilization of computed tomography. Professional societies and advisory bodies consistently recommend against multiplying small doses by large populations to predict excess radiation-induced cancers, in large part because of the potential for sensational claims of health impacts which do not adequately take the associated uncertainties into account. Nonetheless, numerous articles have predicted thousands of future cancers as a result of CT scanning, and this has generated considerable concern among patients and parents. In addition, some authors claim that we now have direct epidemiological evidence of carcinogenic risks from medical imaging. This paper critically examines such claims, and concludes that the evidence cited does not provide direct evidence of low-dose carcinogenicity. These claims themselves have adverse public health impacts by frightening the public away from medically justified exams. It is time for the medical and scientific communities to be more assertive in responding to sensational claims of health risks.

ICRP Publication 127: Radiological Protection in Ion Beam Radiotherapy

The goal of external-beam radiotherapy is to provide precise dose localisation in the treatment volume of the target with minimal damage to the surrounding normal tissue. Ion beams, such as protons and carbon ions, provide excellent dose distributions due primarily to their finite range, allowing a significant reduction of undesired exposure of normal tissue. Careful treatment planning is required for the given type and localisation of the tumour to be treated in order to maximise treatment efficiency and minimise the dose to normal tissue. Radiation exposure in out-of-field volumes arises from secondary neutrons and photons, particle fragments, and photons from activated materials. These unavoidable doses should be considered from the standpoint of radiological protection of the patient. Radiological protection of medical staff at ion beam radiotherapy facilities requires special attention. Appropriate management and control are required for the therapeutic equipment and the air in the treatment room that can be activated by the particle beam and its secondaries. Radiological protection and safety management should always conform with regulatory requirements. The current regulations for occupational exposures in photon radiotherapy are applicable to ion beam radiotherapy with protons or carbon ions. However, ion beam radiotherapy requires a more complex treatment system than conventional radiotherapy, and appropriate training of staff and suitable quality assurance programmes are recommended to avoid possible accidental exposure of patients, to minimise unnecessary doses to normal tissue, and to minimise radiation exposure of staff.

Infrared thermal imaging in the diagnosis of musculoskeletal injuries: a systematic review and meta-analysis

OBJECTIVE

Musculoskeletal injuries occur frequently. Diagnostic tests using ionizing radiation can lead to problems for patients, and infrared thermal imaging could be useful when diagnosing these injuries.

CONCLUSION

A systematic review was performed to determine the diagnostic accuracy of infrared thermal imaging in patients with musculoskeletal injuries. A meta-analysis of three studies evaluating stress fractures was performed and found a lack of support for the usefulness of infrared thermal imaging in musculoskeletal injuries diagnosis.

Predicted cancer risks induced by computed tomography examinations during childhood, by a quantitative risk assessment approach

The potential adverse effects associated with exposure to ionizing radiation from computed tomography (CT) in pediatrics must be characterized in relation to their expected clinical benefits. Additional epidemiological data are, however, still awaited for providing a lifelong overview of potential cancer risks. This paper gives predictions of potential lifetime risks of cancer incidence that would be induced by CT examinations during childhood in French routine practices in pediatrics. Organ doses were estimated from standard radiological protocols in 15 hospitals. Excess risks of leukemia, brain/central nervous system, breast and thyroid cancers were predicted from dose-response models estimated in the Japanese atomic bomb survivors' dataset and studies of medical exposures. Uncertainty in predictions was quantified using Monte Carlo simulations. This approach predicts that 100,000 skull/brain scans in 5-year-old children would result in eight (90 % uncertainty interval (UI) 1-55) brain/CNS cancers and four (90 % UI 1-14) cases of leukemia and that 100,000 chest scans would lead to 31 (90 % UI 9-101) thyroid cancers, 55 (90 % UI 20-158) breast cancers, and one (90 % UI <0.1-4) leukemia case (all in excess of risks without exposure). Compared to background risks, radiation-induced risks would be low for individuals throughout life, but relative risks would be highest in the first decades of life. Heterogeneity in the radiological protocols across the hospitals implies that 5-10 % of CT examinations would be related to risks 1.4-3.6 times higher than those for the median doses. Overall excess relative risks in exposed populations would be 1-10 % depending on the site of cancer and the duration of follow-up. The results emphasize the potential risks of cancer specifically from standard CT examinations in pediatrics and underline the necessity of optimization of radiological protocols.

Risk of cancer associated with cardiac catheterization procedures during childhood: a cohort study in France

BACKGROUND

Radiation can be used effectively for diagnosis and medical treatment, but it can also cause cancers later on. Children with congenital heart disease frequently undergo cardiac catheterization procedures for diagnostic or treatment purposes. Despite the clear clinical benefit to the patient, the complexity of these procedures may result in high cumulative radiation exposure. Given children's greater sensitivity to radiation and the longer life span during which radiation health effects can develop, an epidemiological cohort study is being launched in France to evaluate the risks of leukaemia and solid cancers in this specific population.

METHODS/DESIGN

The study population will include all children who have undergone at least one cardiac catheterization procedure since 2000 and were under 10 years old and permanent residents of France at the time of the procedure. Electronically stored patient records from the departments of paediatric cardiology of the French national network for complex congenital heart diseases (M3C) are being searched to identify the children to be included. The minimum dataset will comprise: identification of the subject (file number in the centre or department, full name, sex, date and place of birth), and characteristics of the intervention (date, underlying disease, type of procedure, technical details, such as fluoroscopy time and dose area product, (DAP), which are needed to reconstruct the doses received by each child). The cohort will be followed up through linkage with the two French paediatric cancer registries, which have recorded all cases of childhood leukaemia and solid cancers in France since 1990 and 2000, respectively. Radiation exposure will be estimated retrospectively for each child. 4500 children with catherizations between 2000 and 2011 have been already included in the cohort, and recruitment is ongoing at the national level. The study is expected to finally include a total of 8000 children.

DISCUSSION

This French cohort study is specifically designed to provide further knowledge about the potential cancer risks associated with paediatric cardiac catheterization procedures. It will also provide new information on typical dose levels associated with these procedures in France. Finally, it should help improve awareness of the importance of radiation protection in these procedures.

Cancer mortality following in utero exposure among offspring of female Mayak Worker Cohort members

Little is known about long-term cancer risks following in utero radiation exposure. We evaluated the association between in utero radiation exposure and risk of solid cancer and leukemia mortality among 8,000 offspring, born from 1948-1988, of female workers at the Mayak Nuclear Facility in Ozyorsk, Russia. Mother's cumulative gamma radiation uterine dose during pregnancy served as a surrogate for fetal dose. We used Poisson regression methods to estimate relative risks (RRs) and 95% confidence intervals (CIs) of solid cancer and leukemia mortality associated with in utero radiation exposure and to quantify excess relative risks (ERRs) as a function of dose. Using currently available dosimetry information, 3,226 (40%) offspring were exposed in utero (mean dose = 54.5 mGy). Based on 75 deaths from solid cancers (28 exposed) and 12 (6 exposed) deaths from leukemia, in utero exposure status was not significantly associated with solid cancer: RR = 0.94, 95% CI 0.58 to 1.49; ERR/Gy = -0.1 (95% CI < -0.1 to 4.1), or leukemia mortality; RR = 1.65, 95% CI 0.52 to 5.27; ERR/Gy = -0.8 (95% CI < -0.8 to 46.9). These initial results provide no evidence that low-dose gamma in utero radiation exposure increases solid cancer or leukemia mortality risk, but the data are not inconsistent with such an increase. As the offspring cohort is relatively young, subsequent analyses based on larger case numbers are expected to provide more precise estimates of adult cancer mortality risk following in utero exposure to ionizing radiation.

Cancer risks associated with external radiation from diagnostic imaging procedures

The 600% increase in medical radiation exposure to the US population since 1980 has provided immense benefit, but increased potential future cancer risks to patients. Most of the increase is from diagnostic radiologic procedures. The objectives of this review are to summarize epidemiologic data on cancer risks associated with diagnostic procedures, describe how exposures from recent diagnostic procedures relate to radiation levels linked with cancer occurrence, and propose a framework of strategies to reduce radiation from diagnostic imaging in patients. We briefly review radiation dose definitions, mechanisms of radiation carcinogenesis, key epidemiologic studies of medical and other radiation sources and cancer risks, and dose trends from diagnostic procedures. We describe cancer risks from experimental studies, future projected risks from current imaging procedures, and the potential for higher risks in genetically susceptible populations. To reduce future projected cancers from diagnostic procedures, we advocate the widespread use of evidence-based appropriateness criteria for decisions about imaging procedures; oversight of equipment to deliver reliably the minimum radiation required to attain clinical objectives; development of electronic lifetime records of imaging procedures for patients and their physicians; and commitment by medical training programs, professional societies, and radiation protection organizations to educate all stakeholders in reducing radiation from diagnostic procedures.

Radiation exposure from CT in early childhood: a French large-scale multicentre study

OBJECTIVES

The increasing use of CT scans in the paediatric population raises the question of a possible health impact of ionising radiation exposure associated with CT scans. The aim of this study was to describe the pattern of CT use in early childhood.

METHODS

In 14 major French paediatric radiology departments, children undergoing at least 1 CT scan before age 5, between 2000 and 2006, were included. For each examination, absorbed organ doses were calculated.

RESULTS

43% of the 27 362 children in the cohort were aged less than 1 year during their first exposure, with 9% being aged less than 1 month. The mean number of examinations per child was 1.6 (range 1-43). The examinations included: head in 63% of the cases, chest in 21%, abdomen and pelvis in 8% and others in 8%. Brain and eye lenses received the highest cumulative doses from head examinations, with mean organ dose values of 22 mGy (maximum 1107 mGy) and 26 mGy (maximum 1392 mGy), respectively. The mean cumulative effective dose was 3.2 mSv (range 0.1-189 mSv).

CONCLUSION

CT scan exposure in childhood is responsible for relatively high doses to radiosensitive organs. The rather large dose range according to the protocols used requires their optimisation. The cohort follow-up will study the risk of long-term radiation-induced cancer.

[Diagnostic radiation exposure in children and cancer risk: current knowledge and perspectives]

The question of the risk of cancer associated with postnatal diagnostic medical exposure involving ionizing radiation in childhood is particularly relevant at the moment given the growing use of diagnostic examinations, especially computed tomography scans, in children. Compared to adults, pediatric patients are more sensitive to radiation and have more years of life expectancy and therefore more years at risk of cancer occurrence as compared to adults. This paper provides a description of diagnostic x-ray exposure in children in France and summarizes epidemiologic studies on subsequent risk of cancer. Overall, this review, based on 12 case-control studies and 6 cohort studies, shows no significant association between exposure to medical diagnostic radiation exposure and childhood cancer risk. The methodological limitations of these studies are discussed. As the expected cancer risks are low, epidemiological studies require very large sample sizes and long periods of follow-up in addition to a good dosimetry assessment to enable quantitative risk estimation. New cohort studies of young patients who underwent CT scans are currently underway within the European EPI-CT project. In the meantime, continued efforts to reduce doses and the number of radiological examinations in children are needed, including adhering to the "as long as reasonably achievable" (Alara) principle.

Childhood cancer risk from conventional radiographic examinations for selected referral criteria: results from a large cohort study

OBJECTIVE

Little is known about the long-term effects of exposure to diagnostic ionizing radiation in childhood. Current estimates are made with models derived mainly from studies of atomic bomb survivors, a population that differs from today's patients in many respects.

MATERIALS AND METHODS

We analyzed the cancer incidence among children who underwent diagnostic x-ray exposures between 1976 and 2003 in a large German university hospital. We reconstructed individual radiation doses for each examination and sorted results by groups of referral criteria for all cancers combined, solid tumors, and leukemia and lymphoma combined.

RESULTS

A total of 68 incidence cancer cases between 1980 and 2006 were identified in a 78,527-patient cohort in the German childhood cancer registry: 28 leukemia, nine lymphoma, six tumors of the CNS, and 25 other tumors. The standardized incidence ratio for all cancers was 0.97 (95% CI, 0.75-1.23). Dose-response relations were analyzed by multivariable Poisson regression. Although the cancer incidence risk differed by initial referral criterion for radiographic examination, a positive dose-response relation was observed in five patients with endocrine or metabolic disease.

CONCLUSION

Overall, we observed no increase in cancer risk among children and youths with very low radiation doses from diagnostic radiation, which is compatible with model calculations. The growing use of CT warrants further studies to assess associated cancer risk. Our work is an early contribution of epidemiologic data for quantifying these risks among young patients.

Bone age assessment by dual-energy X-ray absorptiometry in children: an alternative for X-ray?

OBJECTIVE

The aim of the study was to validate dual-energy X-ray absorptiometry (DXA) as a method to assess bone age in children.

METHODS

Paired dual-energy X-ray absorptiometry (DXA) scans and X-rays of the left hand were performed in 95 children who attended the paediatric endocrinology outpatient clinic of University Hospital Rotterdam, the Netherlands. We compared bone age assessments by DXA scan with those performed by X-ray. Bone age assessment was performed by two blinded observers according to the reference method of Greulich and Pyle. Intra-observer and interobserver reproducibility were investigated using the intraclass correlation coefficient (ICC), and agreement was tested using Bland and Altman plots.

RESULTS

The intra-observer ICCs for both observers were 0.997 and 0.991 for X-ray and 0.993 and 0.987 for DXA assessments. The interobserver ICC was 0.993 and 0.991 for X-ray and DXA assessments, respectively. The mean difference between bone age assessed by X-ray and DXA was 0.11 years. The limits of agreement ranged from -0.82 to 1.05 years, which means that 95% of all differences between the methods were covered by this range.

CONCLUSIONS

Results of bone age assessment by DXA scan are similar to those obtained by X-ray. The DXA method seems to be an alternative for assessing bone age in a paediatric hospital-based population.

Endocrine effects of Fukushima: Radiation-induced endocrinopathy

The unfortunate accidents of Chernobyl and Fukushima have led to an enormous amount of radioactive material being released into the atmosphere. Radiation exposure to the human body may be as a result of accidents, such as those in Chernobyl and Fukushima, or due to occupational hazards, such as in the employees of nuclear plants, or due to therapeutic or diagnostic procedures. These different sources of radiations may affect the human body as a whole or may cause localized damage to a certain area of the body, depending upon the extent and dosage of the irradiation. More or less every organ is affected by radiation exposure. Some require a higher dose to be affected while others may be affected at a lower dose. All the endocrine glands are susceptible to damage by radiation exposure; however, pituitary, thyroid and gonads are most likely to be affected. In addition to the endocrine effects, the rates of birth defects and carcinomas may also be increased in the population exposed to excessive radiation.

Early life exposure to diagnostic radiation and ultrasound scans and risk of childhood cancer: case-control study

OBJECTIVE

To examine childhood cancer risks associated with exposure to diagnostic radiation and ultrasound scans in utero and in early infancy (age 0-100 days).

DESIGN

Case-control study.

SETTING

England and Wales.

PARTICIPANTS

2690 childhood cancer cases and 4858 age, sex, and region matched controls from the United Kingdom Childhood Cancer Study (UKCCS), born 1976-96.

MAIN OUTCOME MEASURES

Risk of all childhood cancer, leukaemia, lymphoma, and central nervous system tumours, measured by odds ratios.

RESULTS

Logistic regression models conditioned on matching factors, with adjustment for maternal age and child's birth weight, showed no evidence of increased risk of childhood cancer with in utero exposure to ultrasound scans. Some indication existed of a slight increase in risk after in utero exposure to x rays for all cancers (odds ratio 1.l4, 95% confidence interval 0.90 to 1.45) and leukaemia (1.36, 0.91 to 2.02), but this was not statistically significant. Exposure to diagnostic x rays in early infancy (0-100 days) was associated with small, non-significant excess risks for all cancers and leukaemia, as well as increased risk of lymphoma (odds ratio 5.14, 1.27 to 20.78) on the basis of small numbers.

CONCLUSIONS

Although the results for lymphoma need to be replicated, all of the findings indicate possible risks of cancer from radiation at doses lower than those associated with commonly used procedures such as computed tomography scans, suggesting the need for cautious use of diagnostic radiation imaging procedures to the abdomen/pelvis of the mother during pregnancy and in children at very young ages.

Diagnostic X-rays and risk of childhood leukaemia

BACKGROUND

The association between diagnostic X-ray exposures early in life and increased risk of childhood leukaemia remains unclear.

METHODS

This case-control study included children aged 0-14 years diagnosed with acute lymphoid leukaemia (ALL, n = 711) or acute myeloid leukaemia (AML, n = 116) from 1995 to 2008. Controls were randomly selected from the California birth registry and individually matched to cases with respect to date of birth, sex, Hispanic ethnicity and maternal race. Conditional logistic regression analyses were performed to assess whether ALL or AML was associated with self-reported child's X-rays after birth (post-natal), including number of X-rays, region of the body X-rayed and age at first X-ray, as well as maternal X-rays before and during pregnancy (preconception and prenatal).

RESULTS

After excluding X-rays in the year prior to diagnosis (reference date for matched controls), risk of ALL was elevated in children exposed to three or more post-natal X-rays [odds ratio (OR) = 1.85, 95% confidence interval (CI) 1.12-2.79]. For B-cell ALL specifically, any exposure (one or more X-rays) conferred increased risk (OR = 1.40, 95% CI 1.06-1.86). Region of the body exposed was not an independent risk factor in multivariable analyses. No associations were observed between number of post-natal X-rays and AML (OR = 1.05, 95% CI 0.90-1.22) or T-cell ALL (OR = 0.84, 95% CI 0.59-1.19). Prevalence of exposure to prenatal and preconception X-rays was low, and no associations with ALL or AML were observed.

CONCLUSIONS

The results suggest that exposure to post-natal diagnostic X-rays is associated with increased risk of childhood ALL, specifically B-cell ALL, but not AML or T-cell ALL. Given the imprecise measures of self-reported X-ray exposure, the results of this analysis should be interpreted with caution and warrant further investigation.

Radiodiagnostic imaging in pregnancy and the risk of childhood malignancy: raising the bar

Eduardo Franco and Guy-Anne Turgeon discuss new findings from Joel Ray and colleagues on the cancer risk following prenatal exposure to radiodiagnostic imaging, and where new research needs to be focused.

A cohort study of childhood cancer incidence after postnatal diagnostic X-ray exposure

Ionizing radiation is an established cause of cancer, yet little is known about the health effects of doses from diagnostic examinations in children. The risk of childhood cancer was studied in a cohort of 92.957 children who had been examined with diagnostic X rays in a large German hospital during 1976-2003. Radiation doses were reconstructed using the individual dose area product and other exposure parameters, together with conversion coefficients developed specifically for the medical devices and standards used at the radiology department. Newly diagnosed cancers occurring between 1980 and 2006 were determined through record linkage to the German Childhood Cancer Registry. The median radiation dose was 7 microSv. Eight-seven incident cases were found in the cohort: 33 leukemia, 13 lymphoma, 10 central nervous system tumors, and 31 other tumors. The standardized incidence ratio (SIR) for all cancers was 0.99 (95% CI: 0.79-1.22). No trend in the incidence of total cancer, leukemia or solid tumors with increasing radiation dose was observed in the SIR analysis or in the multivariate Poisson regression. Risk did not differ significantly in girls and boys. Overall, while no increase in cancer risk with diagnostic radiation was observed, the results are compatible with a broad range of risk estimates.

[Epidemiology of primary brain tumor]

Two main approaches are generally used to study the epidemiology of primary brain tumors. The first approach is to identify risk factors, which may be intrinsic or related to external causes. The second main approach is descriptive. Intrinsic factors potentially affecting risk include genetic predisposition and susceptibility, gender, race, birth weight and allergy. Radiation exposure is the main extrinsic factor affecting risk. A large body of work devoted, among others, to electromagnetic fields and especially cellular phones, substitutive hormonal therapy, pesticides, and diet have been published. To date, results have been discordant. Descriptive epidemiological studies have reported an increasing annual incidence of primary brain tumors in industrialized countries. The main reasons are the increasing age of the population and better access to diagnostic imaging. Comparing incidences from one registry to another is difficult. Spatial and temporal variations constitute one explanation and evolutions in coding methods another. In all registries, weak incidence of primary brain tumors constitute a very important limiting factor. Renewed interest from the neuro-oncological community is needed to obtain pertinent and essential data which could facilitate improved knowledge on this topic.