w. H. ADAMS: LATE MEDICAL CONSEQUENCES OF EXPOSURE TO RADIOACTIVE
THYROID DISEASE vs. RADIATION DOSE
100
-induced cancer.
en equated with cancer
ortality. Since cancer
ment
iber of cases
PERCENT OF POPULATION
IN EACH DOSE CATEGORY
90 +
80 70
1
t
T
T
7
(7) BENIGN NODULES
SJ HYPOTHYROIDISM
|
THYROID CANCERS
7
60 F
4
50
4
SSSHSSSSHHSs
VLLLLLLLLLLLL
fferent types of cancer
40
30
1
20
» ea Ler LAA
10
1-250
051:-500
7
4
_
4
501 “1000 1001-2
-2000 2001 -3000 3001-4000 4001--5000
REM
a
Figure 6.
Thyroid-absorbed radiation dose and subsequent developmentof benign thyroid
nodules, thyroid carcinomas, and hypofunction.
population, both benign nodules and thyroid hypofunction display a similar correlation with
urring cancer mortality,it
g the radiation-exposed
ancer tisk. On the other
lisease, principally of the
sions have been of great
radiation (Figure 6), and in contrast to thyroid cancer, adenomatous nodules have been very
common (Table 6). Adenomatous nodulesare rarely of clinical significance, because they do not
evolve into cancers. Surgery is necessary only to exclude the latter diagnosis. Nevertheless, the
clinical evaluation required to establish a diagnosis is associated with its own morbidity. Prominent
in this morbidity is thyroid surgery itself, a procedure that requires general anesthesia and results in
a cosmetic defect and the unavoidable removal of some normalthyroid tissue.
Thyroid Hypofunction, Radiation-Induced
up have had surgery for
oid nodules found in the
ad adenomatous nodules.
»mas, are benign, and are
c lesions. In the exposed
Overt hypothyroidism was diagnosed in two Rongelap boys who wereinfants at the time of
exposure (11). In addition, subclinical hypothyroidism unrelated to thyroid surgery was confirmed
in twelve other Rongelap persons (22). In 1987, a Utirik man was diagnosed as biochemically
hypothyroid. He was twoyears of age at the time of exposure, and heis the first exposed person
from Utirik to have this diagnosis.
287