title: Thyroid Cancer after Childhood Exposure to External Radiation: An Updated Pooled Analysis of 12 Studies.
abstract: Studies have causally linked external thyroid radiation exposure in childhood with thyroid cancer. In 1995, investigators conducted relative risk analyses of pooled data from seven epidemiologic studies. Doses were mostly <10 Gy, although childhood cancer therapies can result in thyroid doses >50 Gy. We pooled data from 12 studies of thyroid cancer patients who were exposed to radiation in childhood (ages <20 years), more than doubling the data, including 1,070 (927 exposed) thyroid cancers and 5.3 million (3.4 million exposed) person-years. Relative risks increased supralinearly through 2-4 Gy, leveled off between 10-30 Gy and declined thereafter, remaining significantly elevated above 50 Gy. There was a significant relative risk trend for doses <0.10 Gy (P < 0.01), with no departure from linearity (P = 0.36). We observed radiogenic effects for both papillary and nonpapillary tumors. Estimates of excess relative risk per Gy (ERR/Gy) were homogeneous by sex (P = 0.35) and number of radiation treatments (P = 0.84) and increased with decreasing age at the time of exposure. The ERR/Gy estimate was significant within ten years of radiation exposure, 2.76 (95% CI, 0.94-4.98), based on 42 exposed cases, and remained elevated 50 years and more after exposure. Finally, exposure to chemotherapy was significantly associated with thyroid cancer, with results supporting a nonsynergistic (additive) association with radiation.
authors.affiliation: a   Divisions of Cancer Epidemiology and Genetics and.|c   Institute for Radiation Protection and Dosimetry, Brazilian Nuclear Energy Commission, Rio de Janeiro, Brazil;
authors.forename: Lene H S
authors.initials: LH
authors.lastname: Veiga
authors.affiliation: d   Department of Oncology and Radiation Physics and the Oncological Centre, Sahlgrenska University Hospital, Goteborg, Sweden;
authors.forename: Erik
authors.initials: E
authors.lastname: Holmberg
authors.affiliation: e   Department of Cancer Epidemiology, Lund University, Lund, Sweden;|f   Representing the Nordic Countries Childhood Cancer Survival Group;
authors.forename: Harald
authors.initials: H
authors.lastname: Anderson
authors.affiliation: g   Captain, United States Public Health Service (retired), Bethesda, Maryland;
authors.forename: Linda
authors.initials: L
authors.lastname: Pottern
authors.affiliation: h   Cancer and Radiation Epidemiology Unit, The Gertner Institute, Chaim Sheba Medical Center and Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel;
authors.forename: Siegal
authors.initials: S
authors.lastname: Sadetzki
authors.affiliation: i   University of Rochester School of Medicine and Dentistry, Department of Public Health Sciences, Rochester, New York;
authors.forename: M Jacob
authors.initials: MJ
authors.lastname: Adams
authors.affiliation: j   Radiation Effects Research Foundation, Hiroshima, Japan (retired);
authors.forename: Ritsu
authors.initials: R
authors.lastname: Sakata
authors.affiliation: k   University of Illinois College of Medicine, Section of Endocrinology, Diabetes and Metabolism, Chicago, Illinois;
authors.forename: Arthur B
authors.initials: AB
authors.lastname: Schneider
authors.affiliation: a   Divisions of Cancer Epidemiology and Genetics and.
authors.forename: Peter
authors.initials: P
authors.lastname: Inskip
authors.affiliation: l   Program in Epidemiology, Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington;
authors.forename: Parveen
authors.initials: P
authors.lastname: Bhatti
authors.affiliation: m   Oncology, Department of Radiation Sciences, Umeå University, Umeå, Sweden;
authors.forename: Robert
authors.initials: R
authors.lastname: Johansson
authors.affiliation: b   Cancer Control and Population Sciences, National Cancer Institute, NIH, DHHS, Bethesda, Maryland;
authors.forename: Gila
authors.initials: G
authors.lastname: Neta
authors.affiliation: j   Radiation Effects Research Foundation, Hiroshima, Japan (retired);
authors.forename: Roy
authors.initials: R
authors.lastname: Shore
authors.affiliation: n   Cancer Epidemiology Research Unit, National Institute for Health and Medical Research-Institut Gustave Roussy, Villejuif, France;
authors.forename: Florent
authors.initials: F
authors.lastname: de Vathaire
authors.affiliation: m   Oncology, Department of Radiation Sciences, Umeå University, Umeå, Sweden;
authors.forename: Lena
authors.initials: L
authors.lastname: Damber
authors.affiliation: a   Divisions of Cancer Epidemiology and Genetics and.
authors.forename: Ruth
authors.initials: R
authors.lastname: Kleinerman
authors.affiliation: Centre for Childhood Cancer Survivor Studies, Department of Public Health and Epidemiology, University of Birmingham, Birmingham, United Kingdom; and.
authors.forename: Michael M
authors.initials: MM
authors.lastname: Hawkins
authors.affiliation: a   Divisions of Cancer Epidemiology and Genetics and.
authors.forename: Margaret
authors.initials: M
authors.lastname: Tucker
authors.affiliation: p   Department of Medical Physics, Radiumhemmet, Karolinska University Hospital and Karolinska Institute, Stockholm, Sweden.
authors.forename: Marie
authors.initials: M
authors.lastname: Lundell
authors.affiliation: a   Divisions of Cancer Epidemiology and Genetics and.
authors.forename: Jay H
authors.initials: JH
authors.lastname: Lubin
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D004307:Dose-Response Relationship, Radiation; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D009381:Neoplasms, Radiation-Induced / Q000209:etiology*; D013964:Thyroid Neoplasms / Q000209:etiology*; D055815:Young Adult