Thyroid Cancer Risk from In Utero Exposure to Chernobyl Fallout
Maureen Hatch
Workshop on Radiation and Thyroid CancerTokyo, Japan
22 February 2014
• April 26, 1986 accident at ChNPP
• Principal radionuclide: Iodine-131 (I-131)
• I-131 concentrates in the thyroid gland
Chernobyl Nuclear Reactor Accident
Exposure to the Embryo/Fetus
• I-131 uptake begins ~10-12 weeks gestation• Uptake increases faster than thyroid mass
• In late gestation, fetal I-131 levels many-fold higher than maternal levels
• I-131 readily crosses the placenta
Potential Radiosensitivity of the Fetus
• Small thyroid mass
• Rapid cell division
4
Chernobyl Accident Fallout: Ukraine
< 3 7 k B q m -2
5 5 5 -1 4 8 0 k B q m1 4 8 0 -3 7 0 0 k B q m -2-2
-2 3 7 -1 8 5 k B q m1 8 5 -5 5 5 k B q m -2
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SM O L E N S K
B RYA N SK
K A L U G AT U L A
O R E L
K U R SK
PO LTAVA
K H A R K O V
C H E R K A S SY
Z H IT O M IR
R O V N O
Te rn o p o l
K h m e ln itsk iy V IN N IT S A
B erd ich evB e lay a Tserk ov
P in sk
L id a
M o lod ech n oB o riso v
M o zy r
N o v o z y b k o v
K ric h e vC h erik o vB y k ho v
G o rk i
R o s la v l
K iro v
L y u d in o v o
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N aro d ic h i
K o ro s te n
N o v og rad Vo ly n sk iy
S a rn yO v ru ch P rip y a t
S h o s tk a
S lu tsk
S o lig o rsk
N o v og rud o k
C H E R N IG O V
G O M E L
SU M Y
B E L G O R O D
V IL N IU S
M O G IL E V
K IEV
M IN SK
B E L A R U S
U K R A I N E
R U S S I A
E fre m o v
S lav utich
N aro v ly a
B o b ru y sk
Ukraine-American In Utero Study:Objectives
• Estimate risk of thyroid cancer
• Explore incidence of non-thyroid cancer
Ukraine-American In Utero Study: Methods
• For thyroid cancer:
-in-depth screening examinations, 2003-2006
-in-person mother-child interviews
• For non-thyroid cancer:
-record linkage, National Cancer Registry,
1997-2009
• Study area: most affected northern oblasts,
• 2,582 mother-child pairs: Women pregnant on April 26,1986 or the two months following
-1,494 from contaminated areas
-1, 088 from no/low-contaminated areas
(Hatch et al., JCEM, 2009; Likhtarov et al., Health Phys, 2011)
Ukraine-American In Utero Study:Design
Distribution of I-131 Thyroid Dose Estimates
Trimester ATA N Mean, mGy
‘Contaminated’ group
1 400 3.7
2 575 104.2
3 469 206.5
‘Comparison’ group
1 321 0.3
2 276 7.0
3 419 13.1
Statistical Methods
• Estimated EOR/Gy for thyroid cancer
(linear logistic regression models)
sensitivity analyses comparison of radiosensitivity
• Estimated SIRs for non-thyroid cancers
(indirect standardization)
Screening Cases with Thyroid Neoplasia
# Dx Source of dx
Trimester ATA
Sex Age, yr
I-131 dose, mGyTotal Postnatal
1 PTC1 PMC4 3 F 19.9 18.6 4.2
2 PTC PMC 3 F 19.8 421.2 395.2
3 PTC PMC 3 F 19.8 453.6 3.6
4 PTC PMC 3 F 17.7 16.2 0
5 PTC FNA5 2 F 16.5 139.3 0
6 PTC FNA 2 F 20.9 86.4 0
7 FTC2 PMC 1 F 19.4 3.1 0
8 HCN3 FNA 2 M 20.8 33.0 0
1PTC, papillary thyroid cancer. 2FTC, follicular thyroid cancer. 3HCN, Hurthle cell neoplasm. 4PMC, pathomorpology. 5FNA, fine needle aspiration biopsy.
Results: Thyroid Cancer
Outcome EOR1/Gy 95% CI P
In utero
Thyroid cancer or neoplasia3 (n=8)
5.35 NE2-77.29 0.24
Thyroid cancer4 (n=7) 11.66 NE-1,982 0.12
1-5 year old
Thyroid cancer (n=13) 3.24 NE-539 0.01
1Adjusted for sex and age. 2NE, not estimable. 3Exclusion of one case with postnatal I-131 dose > 30 mGy or one case exposed during 1st trimester had little influence on EOR/Gy.4Hurthle cell neoplasm excluded.
Registry-linked Non-thyroid Cancers: 1997-2009
# Diagnosis Trimester ATA
Sex Age, yr
I-131 dose, mGy
1 Hodgkin’s disease 3 M 18.3 309.7
2 Hodgkin’s disease 2 F 20.4 18.4
3 Hodgkin’s disease 1 M 15.7 0
4 Brain cancer, NOS1 3 F 12.3 3.8
5 Diffuse astrocytoma 1 F 14.2 0
6 Choriocarcinoma 2 F 22.1 66.9
1NOS, not specified.
Results: Non-thyroid Cancers
Categories O E1 SIR (O/E)
95% CI
All 6 5.0 1.20 0.47-2.42
Lymphoma 3 1.3 2.28 0.57-5.90
Leukemia 0 0.8 0.00 0.00-2.52
1Estimated by applying sex- and age-specific cancer rates to person-years at risk (assuming different scenarios for losses to follow-up).
Chernobyl Accident Fallout: Belarus
< 3 7 k B q m -2
5 5 5 -1 4 8 0 k B q m1 4 8 0 -3 7 0 0 k B q m -2-2
-2 3 7 -1 8 5 k B q m1 8 5 -5 5 5 k B q m -2
P r i p y a t
Dr
n ep -B u g s k i C a na lP r i p y a t
S to
k ho
d
Go
r yn
’
Be
rezi
na
De s
na
T e t er e
v
De s
na
D n e p r
D n e p rR o s k a
S e y m
S o s n a
Os k
ol
Vo
r sk
l a
Ps e
l
S o z h
Ok a
Ok a
O R SH A
Yele ts
B aranov ich i
SM O L E N S K
B RYA N SK
K A L U G AT U L A
O R E L
K U R SK
PO LTAVA
K H A R K O V
C H E R K A S SY
Z H IT O M IR
R O V N O
Te rn o p o l
K h m e ln itsk iy V IN N IT S A
B erd ich evB e lay a Tserk ov
P in sk
L id a
M o lod ech n oB o riso v
M o zy r
N o v o z y b k o v
K ric h e vC h erik o vB y k ho v
G o rk i
R o s la v l
K iro v
L y u d in o v o
D y a tlo v o
B o lk h o vM ts e n s k
P la v s k
A le k s in
K im o v s k
N o v o-m o sko v sk
K h o yn ikiB rag in
C h ern ob y lP o le ssk oje
N aro d ic h i
K o ro s te n
N o v og rad Vo ly n sk iy
S a rn yO v ru ch P rip y a t
S h o s tk a
S lu tsk
S o lig o rsk
N o v og rud o k
C H E R N IG O V
G O M E L
SU M Y
B E L G O R O D
V IL N IU S
M O G IL E V
K IEV
M IN SK
B E L A R U S
U K R A I N E
R U S S I A
E fre m o v
S lav utich
N aro v ly a
B o b ru y sk
Belarus-Japanese In Utero Study
• Ultrasound thyroid screening study in 2000• School children living 150 km from ChNPP• Thyroid cancer pre/post-accident
• Shibata et al., Lancet 2001
16
Belarus-Japanese In Utero Study
• Group I: born before the accident • Group II: exposed in utero (N=2,409)• Group III: exposed post-natally
OR (II v I) = 11 (3-176)
OR (III v I) = 121 (9-31,000)
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Belarus-American In Utero Study
• Cohort of 3000• Exposed In Utero • Gomel, Mogilev oblasts• Dose reconstruction for I-131 and Cs-137• Linkage with Belarusian Cancer Registry,
Chernobyl State Registry
• Currently in progress
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Summary of Findings to Date:Thyroid Cancer Risk from In Utero Exposure
to Chernobyl Fallout
19
Collaborators
US
• Kiyo Mabuchi Belarus• Alina Brenner • Alexander Rozhko• Andre Bouville • Vasilina Evseenko• Vladimir Drozdovitch • Vladimir Masyakin Evgenia Ostroumova
• Olga Polyanskaya
• Victor Minenko
Ukraine
• Mykola Tronko
• Valery Tereschenko
• Tatiana Bogdanova
• Victor Shpak
• Olexandr Zvinchuk
• Anna Derevyanko
• Evgenie Gorokh
Thank you for your attention