Læknablaðið - 15.01.1995, Page 44

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LÆKNABLAÐIÐ 1995; 81
Árangur geislajoðmeðferðar (131l)
við ofstarfsemi skjaldkirtils
Guðmundur Sigþórsson1,21, Matthías Kjeld1,21
Sigþórsson G, Kjeld M
Results of individually adjusted radioiodine trcat-
ment of hyperthyroidism
Læknablaðið 1995; 81: 34-43
Radioiodine (13II) treatment was started in Iceland
in 1960 and the same formula has been used from the
beginning to calculate the doses of radioactivity aim-
ing for 70 Gy irradiation of the gland. In the present
investigation we studied 468 patients who were
treated over a period of 19 years (1973-1991). About
90% of the patients had Graves’ disease (GD), 9%
toxic adenoma but less than 1% toxic multinodular
goiter. Approximately 70% of the GD patients be-
came hypothyroid (subclinical hypothyroidism in-
cluded) within the first year after a single radioio-
dine treatment and about 80% were hypothyroid
four years after treatment with no significant in-
crease after that. By contrast, only one of 15 patients
with toxic adenoma became hypothyroid after a sin-
gle treatment. For both groups the recurrence rate
of hyperthyroidism was approximately 20%.
The formula used for dose calculation in this study
for GD patients does not seem to be satisfactory.
The smaller glands are getting to much irradiation
and the larger glands to little as can be seen by the
frequency of hypothyroidism in the smaller glands
and recurrences (continuing hyperthyroidism) in the
larger glands after one treatment (table V).
In 1993 blood samples were obtained from a sample
group (n=103) of once 131I treated GD patients and
measurements were done for serum TSFl, T4 and
free T4. One third of the patients who were consid-
ered euthyroid, and therefore not taking T4, were
found to be hypothyroid with elevated TSH and low
FT4 and one third of those taking T4 seemed to be
Frá ” Rannsóknastofu Landspítalans í meinefnafræði, 21
Rannsóknarstofunni i Domus Medica. Fyrirspurnir, bréfa-
skipti: Matthías Kjeld, Rannsóknastofu Landspítalans í
meinefnafræði, 101 Reykjavík.
Lykilorð: Geislajoðmeðferð, Graves sjúkdómur.
overtreated with elevated FT4 and decreased TSH
levels.
It is concluded that the results of the radioiodine
treatment for GD are unsatisfactory and need to be
changed, either by adjusting the present regimen so
that radiation is decreased in the smaller glands but
increased in the larger ones or alternatively, by in-
creasing the radiation dose to all the glands render-
ing the majority of the patients quickly hypothyroid
followed by replacement therapy. The follow up of
patients could be improved.
Ágrip
í rúma þrjá áratugi hefur geislajoðmeðferð
við skjaldvakaóhófi (hyperthyroidism) verið
veitt á Landspítalanum. Gefnir hafa verið
geislaskammtar í þeim tilgangi að ná eðlilegri
starfsemi í skjaldkirtlinum. í þessari rannsókn
var athugaður árangur þeirrar meðferðar á 19
ára tímabili (1973-91). Af 468 sjúklingum sem
meðhöndlaðir voru, höfðu um 90% Graves
sjúkdóm, 9% heita hnúta (toxic adenoma) og
tæplega 1% „toxic multinodular goiter" (heitan
fjölhnúta kepp). Um 70% sjúklinga með Gra-
ves sjúkdóm reyndust komnir með skjaldvaka-
brest (hypothyroidism) ári eftir geislagjöf og
þremur árum síðar var tíðnin orðin 80% en
breyttist lítið úr því. Meðal sjúklinga með heita
hnúta reyndist aðeins einn af 15 vera með
skjaldvakabrest eftir rannsóknartímabilið.
Tæplega fimmtungur sjúklinga úr báðum hóp-
um þurftu fleiri en einn geislaskammt.
Þegar tekið er mið af árangri meðferðarinn-
ar við Graves sjúkdómi virðist sú aðferð sem er
notuð hérlendis við útreikninga á geisla-
skammti vera ófullnægjandi. Litlir kirtlar virð-
ast fá of stóra geislaskammta en stærri kirtlar
of litla skammta.
Skjaldkirtilstarfsemi sem metin var með
hormónamælingum í úrtakshópi (n=103)
sjúklinga með Graves sjúkdóm og meðhöndl-