he insidious onset of thyroid hypofunction and retardation of
growth in the Marshallese children was probably associated with the slow
loss of functioning thyroid cells through lack of replacement due to
radiation impairment of cellular replication. One can speculate that
less injured cells in the thyroid probably responded to the increased
TSH simulation and the picture of concomitant atrophy and hyperplasia
resulted in gross nodule formation. In the 2 cases with complete
thyroid atrophy, however, there must have been sufficient radiation
damage to prevent appreciable responses to TSH stimulation.
No Jvoubt there is increased risk of cancer of the thyroid in the
Marshallese children and it is perhaps chance that no such malignancies
have yet been discovered.
The literature is replete with many retrospective
as well as prospective studies which show the late development of cancer
of the thyroid in children that had been treated with cervical irradiation
during infancy and early childhood.[11-13]
However, there is scant evidence
as yet for the development of cancer of the, thyroid following radioiodine
treatment. Increased prevalence of cancer of the thyroid has been reported
in adults exposed tc the atomic bomb in Hiroshima [14] and other types of
radiation.[15]
It is of course not possible to prove the causal relation-
ship of irradiation in the case of cancer of the thyroid in the exposed
women reported here, but in view of low incidence of such lesions in the
Marshallese, this possibility must be seriously considered.
It is not known whether treatment with thyroid hormone will reduce
the risk of cancer of the thyroid in the human being. However, sch
suppression has been reported to prevent the development of thyroid
nodules in rats.(16]
It is hoped that the hormone treatment being
given the Marshallese may suppress such neoplasia from radiation.
SOC 1bO2