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

Abstract

The risk of cancer after diagnostic X-rays received as fetus or during early childhood has been investigated in many studies. The results of recent epidemiological studies are summarized in a present systematic review. The strategies for literature search, inclusion criteria, and items for study quality assessment were defined in the study protocol. All epidemiological case control and cohort studies published in English between 1990 and 2006 that reported at least the size of the study population and risk estimates were included. Results were summarized separately for pre- and postnatal exposure and for each cancer site. Nineteen case control studies and six cohort studies matched the inclusion criteria. No association of leukemia with prenatal exposures was observed in nine case control studies. Heterogeneous results were found for postnatal exposures and leukemia in four studies. No significant effect of pre- and postnatal X-ray exposure was observed for other cancer sites (non-Hodgkin lymphomas, solid tumors and brain tumors). Most studies have limitations in study design, study size, or exposure measurement, and involve very low exposures. These results thus do not contradict previous evidence accumulated since 1956 indicating risk increases associated with prenatal X-ray exposure. Computed tomography is not covered in the studies and needs to be investigated in the future.

Response to “On pre- or postnatal diagnostic X-rays as a risk factor for childhood cancer review” by R. Wakeford

“…A systematic review." (Schulze-Rath et al 2008).His comment on our systematic review is very interesting and we generally agree with his Wndings. Nevertheless, it is noted that the scope of our review diVered from that of Wakeford's review (Wakeford 2008).…”

“…Thus, the odds ratio (OR) of 1.16 does not compare directly to the one of 0.99 that we found. The diVerence between the two ORs suggests that maternal abdominal X-rays may have a higher cancer risk for the child.The diVerences in the literature included in the two publications (Schulze-Rath et al 2008;Wakeford 2008) may be explained as follows: our inclusion criteria for the literature search were narrower. Studies were included if the publication was written in English and an eVect estimate as OR or relative risk (RR) was reported.…”

Risk Perceptions of Environmental Hazards and Human Reproduction: A Community-Based Survey

“…There is also evidence to suggest a causal relationship between air pollution and fetal growth but the association is small and it is difficult to determine which particulates are most harmful [15][16][17][18]. However, there is equivocal or conflicting evidence on the associations between effects on the fetus and diagnostic X-rays [31], nonionizing radiation [20,21], exposure to hair products [26], and nitrates in drinking water [24].…”

Suivi d’enfants exposés aux rayonnements ionisants dans le cadre de procédures radiologiques à visée diagnostique

“…Au cours des 30 dernières années, de nombreuses données épidémiologiques ont été rassemblées concernant des populations (tous âges confondus) exposées à des rayonnements ionisants d'origine médicale, à visée thérapeutique ou diagnostique (Schutz-Rath et al, 2008 ;Linet et al, 2009). Néanmoins ces études sont difficilement comparables entre elles puisqu'elles incluent des populations de tailles très différentes (de quelques centaines à quelques milliers de patients), hétérogènes en âge puisque certaines incluent des enfants mais également des jeunes adultes et de qualité méthodologique variable (Baysson et al, 2012 (Boice et al, 1991 ;Howe et McLaughlin, 1995 ;Doody et al, 2000 ;Ronckers et al, 2010).…”