Thyroid cancer and I-131

[maay100@bgumail.bgu.ac.il (Quastel)]

Bjorn Cedervall's comment regarding different adult and childhood thyroid
sensitivities to radiation is relevant since, as he mentions, the L-E Holm
studies were conducted with adults.

There seems to be little doubt that the significant increase of childhood
cancer (though not adult cancer) of the thyroid in Belarus and Ukraine was
caused by incorporated Chernobyl radioiodines (I-131 together with the more
short lived I-132, I-133 and I-135 (with half lives of 2.3 hrs, 21 hrs &
6.7 hrs respectively). Although dosimetry has been very difficult for these
populations, it seems likely that the thyroids of young children are more
radiosensitive than those of adults

In Belarus and the Ukraine the increased incidence of childhood thyroid
cancer has been found yearly since 1990 ( Kazakov et al,1992; Baverstock et
al, 1992; Likhtarov et al,1995)  Most investigators have gone on record as
supporting the likelihood that the increase of cancer of thyroid is real
(Abelin, 1994). Williams (1994) rather than a consequence of improved
surveillance.

Other evidence for (non-malignant) radiation effects of environmental
radioiodine in chidren include a recent report of juvenile hypothyroidism
in 2 exposed populations, one being the Hanford downwinders and the second
being the population living in regions near Chernobyl (Goldsmith et al
1999).

Abelin, T. (1994) Thyroid cancer in Belarus post-Chernobyl: Improved
detection or increased incidence. Soz Präventivmed 39, 189-197.

Baverstock,K.et al (1992) Thyroid cancer after Chernobyl. Nature 359, 21-22.

Kazakov, V. et al (1992) Thyroid cancer after Chernobyl. Nature 359, 21.

Likhtarev, I.A. et al (1995) Thyroid cancer in the Ukraine. Nature 375, 365.

Goldsmith JR et al (1999) Juvenile hypothyroidism among 2 populations
exposed to radioiodine. Environ Health Perspect 107:303-308 (1999).

Williams, E.D. (1994) Chernobyl, eight years on. Nature 371, 556.

                                        Mike Quastel
                                        Nuclear Medicine
                                        Soroka Medical Center and
                                        Faculty of Health Sciences,
                                        Ben Gurion University of the Negev
                                        Beer Sheva, Israel
                                        maay100@bgumail.bgu.ac.il

---------------------------------------------------------------------------
>Just a comment: The L-E. Holm studies on I-131 and treatment for
>hyperthyroidism (from around 15-20 yrs ago) concerned only adults. I think
>that it is always important to make this distinction. I have seen a "green"
>discussion about childhood thyroid cancer and then refs. to L-E. Holm's work
>(to downgrade it) without a proper note about the child/adult difference.
>Did Dr. R. Yalow publish any research studies on the risks of I-131 BTW (did
>I miss any references?)?
>
>bjorn_cedervall@hotmail.com
>Any opinions expressed above are those of mine and may not necessarily
>coincide with those of others.
>
>
>
>
>______________________________________________________
>Get Your Private, Free Email at http://www.hotmail.com
>************************************************************************
>The RADSAFE Frequently Asked Questions list, archives and subscription
>information can be accessed at http://www.ehs.uiuc.edu/~rad/radsafe.html


************************************************************************
The RADSAFE Frequently Asked Questions list, archives and subscription
information can be accessed at http://www.ehs.uiuc.edu/~rad/radsafe.html