Kc. Loh et al., THE TREATMENT OF MALIGNANT METAIODOBENZYLGUANIDINE (I-131-MIBG) - A COMPREHENSIVE REVIEW OF 116 REPORTED PATIENTS, Journal of endocrinological investigation, 20(11), 1997, pp. 648-658
Iiodine-131 metaiodobenzylguanidine (I-131-MIBG), a radiopharmaceutica
l agent used for scintigraphic localization of pheochromocytomas, has
been employed to treat malignant pheochromocytomas since 1983 in a few
specialized centers around the world. We review our clinical experien
ce together with the published experience of 23 other centers in 10 co
untries, regarding the use of I-131-MIBG for treating patients with ma
lignant adrenal pheochromocytomas or extra-adrenal paragangliomas. The
re were a total of 116 evaluable patients: 3 were from our current rep
ort and another 113 were reported in the literature from 1983 to 1996.
A majority of the patients were selected for treatment based upon pos
itive tracer uptake studies, The cumulative dose of I-131-MIBG adminis
tered ranged from 96 to 2,322 mCi (3.6 to 85.9 GBq), with a mean (+/-S
D) of 490+/-350 mCi (18.1+/-13.0 GBq). The subjects received a mean si
ngle therapy dose of 158 mCi (5.8 GBq) and the number of doses adminis
tered ranged from 1 to 11, with a mean of 3.3+/-2.2 doses. Initial sym
ptomatic improvement was achieved in 76% of patients, tumor responses
in 30%, and hormonal responses in 45%. Five patients had complete tumo
r and hormonal responses, ranging from 16 to 58 months, which were sus
tained at the time of reporting. Patients with metastases to soft tiss
ue had more favorable responses to treatment than those with metastase
s to bone. No difference was noted in the age between the responders a
nd non-responders. Adverse effects, recorded in 41% of the treated pat
ients, were generally mild except for one fatality from bone marrow ap
lasia. Among 89 patients with follow-up data, 45% of the responders ha
d relapsed with recurrent or progressive disease after a mean interval
of 29.3+/-31.1 months (median 19 months). Of patients with an initial
response to I-131-MIBG, death was reported in 33% after a mean of 23.
2+/-8.1 months(median 22 months) following treatment. Of non-responder
s, death was reported in 45% after a mean of 14.3+/-8.3 months (median
13 months). In conclusion, this review suggests that I-131-MIBG thera
py may be a useful palliative adjunct in selected patients with malign
ant pheochromocytoma or paraganglioma. Although controlled studies are
lacking, our review raises the hope that this therapeutic modality ma
y prolong survival with an occasional sustained complete remission or
possible cure. (C) 1997, Editrice Kurtis.