Page 133 - 2018_11-Haematologica-web

Acute Lymphoblastic Leukemia
Radiation exposure from computerized tomography and risk of childhood leukemia: Finnish register-based case-control study of childhood leukemia (FRECCLE)
Atte Nikkilä,1 Jani Raitanen,2,3 Olli Lohi1,4 and Anssi Auvinen2,3,5
1Faculty of Medicine and Biosciences, University of Tampere; 2Faculty of Social Sciences, University of Tampere; 3UKK Institute for Health Promotion Research, Tampere; 4Tampere Center for Child Health Research, University of Tampere and Tampere University Hospital and 5STUK – Radiation and Nuclear Safety Authority, Helsinki, Finland
ABSTRACT
The only well-established risk factors for childhood leukemia are high-dose ionizing radiation and Down syndrome. Computerized tomography is a common source of low-dose radiation. In this study, we examined the magnitude of the risk of childhood leukemia after pediatric computed tomography examina- tions. We evaluated the association of computed tomography scans with risk of childhood leukemia in a nationwide register-based case- control study. Cases (n=1,093) were identified from the population- based Finnish Cancer Registry and three controls, matched by gender and age, were randomly selected for each case from the Population Registry. Information was also obtained on birth weight, maternal smoking, parental socioeconomic status and background gamma radi- ation. Data on computed tomography scans were collected from the ten largest hospitals in Finland, covering approximately 87% of all pediatric computed tomography scans. Red bone marrow doses were estimated with NCICT dose calculation software. The data were ana- lyzed using exact conditional logistic regression analysis. A total of 15 cases (1.4%) and ten controls (0.3%) had undergone one or more com- puted tomography scans, excluding a 2-year latency period. For one or more computed tomography scans, we observed an odds ratio of 2.82 (95% confidence interval: 1.05 – 7.56). Cumulative red bone marrow dose from computed tomography scans showed an excess odds ratio of 0.13 (95% confidence interval: 0.02 – 0.26) per mGy. Our results are consistent with the notion that even low doses of ionizing radiation observably increase the risk of childhood leukemia. However, the observed risk estimates are somewhat higher than those in earlier studies, probably due to random error, although unknown predispos- ing factors cannot be ruled out.
Introduction
Leukemia is the most common childhood malignancy.1 The incidence rates of childhood leukemia in Finland are comparable to those in other European coun- tries and show a slight increasing trend up to the 1990s.2 Acute lymphoblastic leukemia accounts for approximately 85% of all childhood leukemias. The major histological subtype of acute lymphoblastic leukemia is precursor B-cell acute lym- phoblastic leukemia (~85%).1
Well-established risk factors for childhood leukemia include high doses of ion- izing radiation, alkylating chemotherapy agents, as well as Down syndrome and some rare congenital syndromes such as Fanconi anemia, Bloom syndrome and ataxia telangiectasia.1,3-6 A number of genetic variants have also been associated
Ferrata Storti Foundation
Haematologica 2018 Volume 103(11):1873-1880
Correspondence:
atte.nikkila@uta.fi
Received: January 6 2018. Accepted: June 26, 2018. Pre-published: July 5, 2018.
doi:10.3324/haematol.2018.187716
Check the online version for the most updated information on this article, online supplements, and information on authorship & disclosures: www.haematologica.org/content/103/11/1873
©2018 Ferrata Storti Foundation
Material published in Haematologica is covered by copyright. All rights are reserved to the Ferrata Storti Foundation. Use of published material is allowed under the following terms and conditions: https://creativecommons.org/licenses/by-nc/4.0/legalcode. Copies of published material are allowed for personal or inter- nal use. Sharing published material for non-commercial pur- poses is subject to the following conditions: https://creativecommons.org/licenses/by-nc/4.0/legalcode, sect. 3. Reproducing and sharing published material for com- mercial purposes is not allowed without permission in writing from the publisher.
haematologica | 2018; 103(11)
1873
ARTICLE