47
- range 700 to 1400 rads). The fact that a part of the
total dose to the thyroid (175 rads) was due to
whole-body gamma exposure (including the pituitary gland) maybe of somesignificance.
The fact that all three Marshallese developing
the thyroid nodules weregirls is in accord with the
experience of others that thyroid neoplasia and
goiters predominatein females. In the report by
Sheline et al.*° referred to above, 8 cases among
256 patients treated with I**' developed thyroid
nodules. All 8 cases were females: the ages at the
time of treatmentin 6 were <(18 (4 aged <10 and
2 between 20 and 30). In the Marshallese girls, the
stress of puberty may have beena factorin the developmentof the nodules.
Nore: During the 11th-year survey now in progress (March 1965) 3 newcases of thyroid nodules
in the exposed group have been detected. Two
were in boys 12 and 17 years of age and one in an
adult woman 41 years of age. The nodules ap-
peared grossly similar to those described in the
teen-age girls in this report, and these cases will
receive study and treatment.
MALIGNANCY |
Two older women who had been exposed died
with a diagnosis of cancer, one at 67 years of age
of ovarian malignancy at 5 years post exposure
andthe otherat 60 years of age of probable cancer
ofthe cervix at 8 years post exposure. The diagnosis
in the latter case was not confirmed by autopsy or
biopsy. One unexposed older woman died possibly
of cancer of the cervix, but the diagnosis was not
confirmed. No other cases of malignancy have
been noted in the unexposed population.
No cases of leukemia have been detected in
either the exposed or unexposed Rongelapese. Peripheral blood smears were studied closely for leukemic cells, including examinationsfor alkaline
phosphatase and basophil counts.
Thethree cases of thyroid nodules plus the two
earlier cases of cancer in older exposed women
raise the question whether an increased frequency
of cancer may be expected in future years. However, in evaluating the role of radiation, it must be
kept in mind that one case of cancer in the ex-
posed group occurred at 5 years after exposure —
too soon, it is believed, to be related to radiation
7]
Cc
CD
|
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Cc
cs
exposure — andin the second caseit was not possible to obtain autopsy or biopsy material for con-
firmation of the diagnosis. Atomic Bomb Casualty
Commission studies have conclusively demonstrated an increased incidence of leukemia in Japanese exposed to the atom bombradiation.**-*° An
increased incidence hasalso been notedin patients
who hadreceived radiation therapy for ankylosing
spondylitis.*' There are many reports of the late
developmentof neoplasia, particularly cancer of
the thyroid gland,following radiation exposure of
infants and children.*?-** Increased instances of
cancerof the thyroid gland and adenomata have
been reported in the Japanese heavily exposed to
ionizing radiation from the atomic bombs.*7-*
The Marshallese will be carefully observed for
such a possibility in future surveys. The question
of increased incidence of malignancy in the irradiated Marshallese must be left open for the
present.
“BETA BURNS”
During the past several years, increased numbers of pigmented nevus-like lesions have been’
noted in previously irradiated areas of the skin,
but these have appeared to be quite benign.
Neither chronic radiation dermatitis nor cancers
of the skin have been noted.
INTERNALLY ABSORBED ISOTOPES
Radiochemicalurine analyses and whole-body
gammaspectrometric analyses revealed that the
level of body burdensof radioisotopes in the exposed Rongelapesefell rapidly, so that by 2 and 3
years post exposurethe levels were far below the
stated maximum permissible level.+° The return
of the Rongelapese to their homeisland wasassociated with a rise in their body burdensof Cs’*’,
Zn**, and Sr®*’. By 1961, the whole-body content
of Cs'*" had apparently reached an equilibrium
with the environment at a value of about 14.7
mpC/kg body weight or about 300 times the mean
of the medical team measured at the sametime.
Zn°*, which hadrisen to about 9.9 mpC in 1959,
fell by 1961 to 1.5 mpC/kg body weight, or about
100 times that measured in membersof the medical team. The levels of Sr°® in 1962 and 1963 hov-
ered around the 12.0-mpC level in adults and
about 22 mpCin children, about 5 and 10% of
the maximum permissible level (for members of
the population at large). It thus appears that body