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The International Workshop on Radiation and Thyroid Cancer, 21 – 23 February 2014 ,Tokyo, Japan. Childhood Thyroid Cancer in Ukraine Following the Chernobyl accident.
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The International Workshop on Radiation and Thyroid Cancer, 21 – 23 February 2014 ,Tokyo, Japan Childhood Thyroid Cancer in Ukraine Following the Chernobyl accident Tronko M.1*, Bogdanova T.1 , Mabuchi K.2, Hatch M.2, Likhtarev I.3, Bouville A.2, Oliynik V.1, Shpak V.1, Tereshchenko V.1, Brenner A.2, Zurnadzgy L.1, Zamotaeva G.1, Gulak L.4, Shchepotin I.4 1Institute of Endocrinology and Metabolism, Kyiv, Ukraine 2U.S. National Cancer Institute, Bethesda, U.S.A 3Scientific Centre for Radiation Medicine, Kyiv, Ukraine 4 Ukrainian National Cancer Institute, Kyiv, Ukraine
Comparison of radioactive iodine I131fallout from nuclear reactors 15-20 40 000 000 – 50 000 000 4 000 000 – 5 000 000 * In addition, fallouts of short-lived iodine and tellurium isotopes are estimated to be equal to 100,000,000 Curie (UNSCEAR 2008). ** Report of Japanese Government to IAEA Ministerial Conference on Nuclear Safety - Accident at TEPCO's Fukushima Nuclear Power Stations, 7 June 2011
Cumulative fallout of I131 in the territory of Ukraine as a result of the Chernobyl accident (April 26th – May 7th, 1986) Cumulative I-131 fallout on the soil (MBq/m2) 0.16mean regional values of I131 fallout (kBq/m2) Likhtarev et al., “Radiationandrisk", 2005
Main components of Clinical-Morphological Registry (CMR) Preliminary activity 1990– 1991 Formally established by Ukraine Ministry of Public Health in order N12 January 20th, 1992 “On the improvement of endocrinological care to children and adolescent with thyroid diseases”
Cooperation between CMRand some other projects TherDep, IEM, Kiev National Cancer Registry of Ukraine, National Cancer Institute, Ukraine, Kiev Clinical-Morphological Register, IEM, Kiev Chernobyl Tissue Bank
Current number of thyroid cancer cases registered in CMR(1986 – 2012)
Time trends of thyroid cancer incidence in 6 and 21 regions of Ukraine among children aged 0-14 years at the time of accident
Time trends of thyroid cancer incidence in 6 and 21 regions of Ukraine among adolescents aged 15-18 years at the time of accident
Time trends of thyroid cancer incidence in 6 and 21 regions of Ukraine among children aged 0-14 years at surgery
Time trends of thyroid cancer incidence in 6 and 21 regions of Ukraine among adolescents aged 15-18 years at surgery
Time trends of thyroid cancer incidence in 6 and 21 regions of Ukraine among adults aged 19+ years at surgery
Distributions of thyroid cancer cases by age at exposurein Ukraine and Fukushima 12 thyroid cancer cases revealed in 6 regions of Ukraine in 1986-1988 111 thyroid cancer cases revealed in 6 regions of Ukraine in 1990-1992 59 suspicious or thyroid cancer cases, detected on September 30, 2013 in results of examination 238 789 Japan children (Proceedings of the 13th Prefectural Oversight Committee Meeting for Fukushima Health Management Survey. Thyroid Ultrasound Examination. 12 November 2013)
Histological types of thyroid carcinomas PTC – papillary thyroid carcinoma; FC – follicular carcinoma; MTC – medullary carcinoma; PDC – poorly differentiated carcinoma
Ukrainian-American Thyroid Project UkrAm cohort thyroid study – a classical prospective cohort study of radiation risk of thyroid cancer and other thyroid pathology in Ukrainian exposed as children and adolescent due to Chernobyl accident and having direct thyroid activity measurements in May-June 1986. Stezhko et al., Rad. Res., 2004
Distribution of selected and examined cohort by dose group Total number of records selected from dose file 34092 Dose group A D<0,3Gy Low dose 15541(45.6%) Dose group B 0,3<D<1,0Gy Middle dose 8476(24.9%) Dose group C D>1,0Gy High dose 10075 (29.6%) Number of cohort members examined 13243 Dose group A 7542 (57.0%) Dose group B 3457 (26.1%) Dose group C 2244 (16.9%)
Geographic distribution of cohort members that underwent examination in 1998-2000
Number of cohort members that underwent different screening rounds
Standardized clinical examination procedure Thyroid palpation Ultrasoundexamination FNA test and surgery (if recommended) Individual medical history documentation Blood sample to determine thyroid hormone levels Urinary iodine content test Extended structured dosimetry interviews Endocrinology conclusion and recommendations
Nodular pathology examination Ultrasound examination No thyroid nodular abnormality Thyroid nodule or lesion FNA test I. Non informative FNA Next exam two years after Thyroid nodule or lesion, FNA not recommended II. Benign nodular goiter IV. Suspected carcinoma V. Carcinoma III. Follicular neoplasia Next exam six months after Thyroid surgery, Pathology diagnosis, IPP (CTB) verification Thyroid benign pathology Thyroid carcinoma
Thyroid cancer cases revealed during the 1st, 2nd, 3rd and 4th cycles of screening (110 cases) 60 (18+21+11+10) 29(17+5+1+6) 21 (10+6+5+0)
Number of thyroid cancer cases per 1,000 study subjects detected during 1st- 4th screening cycles Number of cases Number per 1000 subjects in each dose group
Prospects for scientific investigations • Assessment of the risk for thyroid cancer as a result of the Chernobyl accident
UkrAm: estimates of thyroid cancer risk Prevalence: cases diagnosed in 1998-2000 Tronko M.D., Howe G.R., Bogdanova T.I. et al. JNCI, Vol. 98, 2006 Dose-response prevalence of thyroid cancers detected during first screening cycle (1998-2000) • In the cohort 13127 screened subjects during 1998-2000 45 thyroid cancer cases were detected. • The excess relative risk per gray (Gy) was estimated using individual doses and a linear excess relative risk model. • Thyroid cancer showed a strong, monotonic, and approximately linear relationship with individual thyroid dose estimate ( P <.001), yielding an estimated excess relative risk of 5.25 per Gy (95%CI = 1.70 to 27.5). In the absence of Chernobyl radiation, 11.2 thyroid cancer cases would have been expected compared with the 45 observed.
UkrAm: estimates of thyroid cancer risk Incidence: cases diagnosed in 2001-2008 BrennerA.V.,Tronko M.D., Hatch М., BogdanovaT.I. et al. EHP, March 2011, doi: 10.1289/ehp.1002674 I-131 Dose-Response for Incident Thyroid Cancers in Ukraine Related to the Chernobyl Accident • There were 65 incident thyroid cancers diagnosed during the 2nd-4th screenings in 2001-2008 (N=12514 ) and about 73,000 person-years of observation. • The ERR per Gy was estimated 1.91 (95% CI: 0.43-6.34) and EAR per 104 PY per Gy was 2.21 (95% CI: 0.04 - 5.78). The ERR per Gy varied significantly by oblast of residence, but not by time since exposure. I-131-related thyroid cancer risks persisted for two decades following exposure.
CONCLUSIONSI Among the exposed population of children and adolescents (aged 0-18 years at the time of accident) observed a significant increase in thyroid cancer incidence beginning from 1990. This tendency persists for the period of 22 years (1990-2012). Incidence rate in the 6 most contaminated regions exceeded that in 21 low-contaminated regions for all periods of study. By age at surgery, peak incidences in childhood and adolescent groups were observed in 1996-1998 and 2000-2002, respectively. Age distribution of subjects with radiogenic thyroid cancer in Ukraine for shortest latency of tumor development (4-6 years) is characterized by realization of radiation effect in youngest groups at the time of the accident and significantly differs from that observed in Fukushima after screening examinations.
CONCLUSIONSII The number of thyroid cancer cases per 1,000 study subjectsof UkrAm thyroid cohort study was decreasing with each subsequent screening but after the fourth two-year cycle it also remained at a significant level: 1.5 cases per 1000 study subjects. During the first and second cycles the number of thyroid cancer cases per 1,000 study subjects was increasing with increasing of thyroid exposure doses. During third and fourth cycles of screening such relationship has not been established. As a result of four cycles of screening examinations, 110 cohort members with thyroid cancer have been operated on during 1998-2008. Among 110 thyroid carcinomas revealed during four screenings papillary carcinoma was predominant: 104 cases (94.5%).