How often should patients be reviewed after treatment with iodine-131 for thyrotoxicosis?

Six to 18 years after treatment with iodine-131 for thyrotoxicosis 69 euthyroid patients with raised serum thyrotrophin (TSH) concentrations (mean 25.0 +/- SE 2.0 mU/l) and 61 with normal concentrations (mean 4.0 +/- 0.2 mU/l) were included in a prospective five-year follow-up study beginning in 1972. During this period 13 patients from the original group with raised serum TSH concentrations became hypothyroid. In contrast it was five years before hypothyroidism developed in a single patient from the group with normal serum TSH concentrations in 1972, although raised concentrations were recorded in 19 of these patients during the study.     

131I]metaiodobenzylguanidine therapy after conventional therapy for neuroblastoma.

[131I]Metaiodobenzylguanidine (131I-MIBG) is used for diagnostic scintigraphy and targeted therapy in a range of neural crest tumors, which exhibit an active uptake-1 mechanism at the cell membrane and cytoplasmatic storage in neurosecretory granules. A good and selective concentration and a long retention in the tumor, as is generally the case in neuroblastoma, are the basis for successful 131I-MIBG treatment. At The Netherlands Cancer Institute a phase II study was carried out in 53 patients with progressive recurrent disease after conventional therapy had failed. Despite the unfavorable basis for treatment, 131I-MIBG therapy induced 7 complete remissions, 23 partial remissions and arrest of disease (no change) in 10. Nine patients had progressive disease and one patient was lost to follow-up. The palliative effect of the treatment under these conditions was impressive. The duration of remissions varied from 2 to 38 months. The best results were obtained in patients with voluminous soft tissue disease. In general the treatment was well tolerated by children and the toxicity was mild, provided the bone marrow was not invaded by the disease. It is concluded that 131I-MIBG therapy has a definitive place in the treatment of neuroblastoma after conventional treatment has failed. As the invasiveness and toxicity of this therapy compare favorably with that of chemotherapy, immunotherapy and external beam radiotherapy, 131I-MIBG therapy is the best palliative treatment for patients with advanced recurrent neuroblastoma.     

Surgical treatment of thyrotoxicosis.

A retrospective study of thyrotoxic patients treated by subtotal thyroidectomy between 2 and 21 years ago in the north-east of Scotland showed that 20% of the patients could not be identified or traced at the time of the survey. The thyroid status of 40% of patients followed up was abnormal.It is now accepted that radioiodine treatment of thyrotoxicosis is followed by a significant incidence of late onset hypothyroidism, and life-long follow-up is regarded as obligatory. The findings in this study indicate that similar methods of aftercare are required for surgically treated patients and for all patients receiving thyroxine-replacement therapy.     

131I uptake in human thyroid after antidote treatment for mixed fission products contamination

The efficacy of a mixed antidote treatment in blocking 131I uptake in humans was investigated in two volunteers. Simultaneous oral administration of 10 g of calcium alginate, 3 g of ferrihexacyanoferrate (II) and 130 mg of potassium iodide 30 min before 131I administration caused an almost complete block of the 131I thyroid uptake in both subjects. This indicated that calcium alginate and ferrihexacyanoferrate (II) had no influence on the blocking effect of potassium iodide on 131I thyroid uptake. This finding is important because mixed antidote treatment is the recommended treatment in cases of accidental exposure to mixed fission products.     

131I]metaiodobenzylguanidine treatment of a malignant paraganglioma.

The bone metastases of a malignant, non-secreting paraganglioma were treated with [131I]metaiodobenzylguanidine (131I-MIBG) over a 10-year period. Initial treatment (131I-MIBG: 9.6 GBq) resulted in a decrease in the number of bone metastases from 16 to 2. At three years, a relapse with primary tumor regrowth and liver metastasis was again treated with 131I-MIBG (22.2 GBq). A decrease in the number of bone metastases and MIBG uptake was again observed.     

The use of [131I]metaiodobenzylguanidine in the treatment of neuroblastoma after conventional therapy.

Eleven cases of neuroblastoma (10 males and 1 female; 9 aged 1-13 years, and two aged 17 and 38 years, respectively) ten of which were refractory to chemotherapy, were submitted to treatment with [131I]metaiodobenzylguanidine (131I-MIBG). The therapeutic procedure consisted essentially of single doses (2.6-9.5 GBq) of 131I-MIBG mostly split into two parts, administered by slow i.v. infusion and given in several therapeutic courses, usually at 1-2 month intervals. The treatment resulted in: 1 complete response, 1 partial response, 1 minor response, 4 stabilized diseases and 2 progressive diseases (two patients were not evaluable due to rapid progression of the disease). Pain relief was observed in all cases and particularly in four patients who suffered severe tumor pain. The major side-effects recorded were: hypertensive crises over a 6-day period in one case, fever lasting a few days in another and bone marrow depression in two intensively pretreated patients. A slight hematologic toxicity was observed, however, in almost all cases.     

131I]metaiodobenzylguanidine in neuroblastoma patients at diagnosis.

Treatment of resistant neuroblastoma with high dosage [131I]metaiodobenzylguanidine (131I-MIBG) appears effective since encouraging results have been obtained so far even in patients with very advanced, intensively pre-treated disease. We have already reported a stage III NB patient treated at diagnosis, who is at present in complete remission with a 4-year follow-up. To further explore the potential role of this new drug in untreated patients, we administered radionuclide to two children with stage III neuroblastoma. Both cases received 131I-MIBG at relatively low doses, and showed a significant reduction of the tumor mass and, interestingly enough, no evidence of 131I-MIBG uptake of a tracer dose in the remaining tumor. Particularly in case 1, the permanence and subsequent progression of the part of the tumor mass without 131I-MIBG uptake, after therapeutic doses of 131I-MIBG which apparently destroyed the 131I-MIBG-positive cell population, clearly suggest heterogeneity at diagnosis, with a dual neuroblastoma cell population, one with 131I-MIBG uptake and the other without. Aside from the biological implications of the heterogeneous MIBG uptake in neuroblastoma at diagnosis, our findings suggest that in stage III neuroblastoma patients even a relatively small dose of 131I-MIBG administered at diagnosis is sufficient to either completely destroy the primary tumor, as reported by our group, or to destroy that part of the tumor which shows 131I-MIBG uptake (as in the present cases), without any significant hematologic toxicity. Furthermore, a single course of 131I-MIBG at the dosage employed here does not appear to jeopardize the subsequent use of chemotherapy.(ABSTRACT TRUNCATED AT 250 WORDS)     

Results of [131I]metaiodobenzylguanidine treatment in metastatic carcinoid.

The results obtained with [131I]metaiodobenzylguanidine (131I-MIBG) treatment in 6 patients affected by metastatic carcinoid are reported. 131I-MIBG was given in single doses of 3.7-8.0 GBq, reaching a maximum cumulative dose of 29.5 GBq in 4 courses. Objective responses were not observed, but in 4 cases an apparent stabilisation of the disease for more than 1 year was obtained. A subjective response regarding the carcinoid syndrome was observed in 4 cases. No response was seen in 2 cases. No adverse side-effects of any importance were observed, usually being prevented by a mild medication.     

Results of [131I]metaiodobenzylguanidine treatment in metastatic malignant phaeochromocytoma.

The results obtained with [131I]metaiodobenzylguanidine (131I-MIBG) treatment in 6 patients affected by metastatic phaeochromocytoma are reported. Single doses of 3.7-7.4 GBq were given, in 1-6 courses, up to cumulative doses of 5.4-37.8 GBq. Objective responses were observed in 5 patients (2 tumour shrinkages, even if small; 5 lowering of blood pressure), which were only temporary in 3 patients and stable in 2. Complete disappearance of pain was obtained in 2/2 patients. No adverse side-effects were observed. The problem of treatment strategy in situations of stable disease deserves further study.