131I]metaiodobenzylguanidine therapy of malignant pheochromocytoma: interference of medication

Malignant pheochromocytoma may present as a widespread metastatic disease, which is little or non-responsive to external beam radiotherapy and chemotherapy. The prognosis of these patients is bad due to both the progressive metastasis and the secretion of excess catecholamines which may cause hypertensive episodes. For these conditions [131I]metaiodobenzylguanidine (131I-MIBG) therapy may be an alternative treatment modality to induce both tumor remission and reduction of hormonal activity of the disease. The experience with 131I-MIBG therapy in four patients with metastatic malignant pheochromocytoma at The Netherlands Cancer Institute is reviewed. One patient with abdominal tumor recurrence and metastases to the lymph nodes and lungs had a partial remission of disease for 3 years; a second had a mixed response together with palliation and two other patients had stable disease, but were relieved of bone pain and severe hypertension, respectively. It is essential to be aware of the medication the patient is using, as many drugs are known or may be expected to interfere with the uptake and/or retention of 131I-MIBG by the tumor cells. The case of a significant reduction of 131I-MIBG uptake and retention by Labetalol in one of the patients is discussed. It is concluded that 131I-MIBG therapy may induce objective remission in patients with malignant pheochromocytoma and is certainly meaningful in the reduction of hormonal activity, the control of hypertension and the relief of pain from metastases.     

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.     

Proteinuria in metastatic pheochromocytoma is associated with an increased risk of Acute Respiratory Distress Syndrome, spontaneously or after therapy with 131i-meta-iodobenzylguanidine (131I-MIBG)

Acute Respiratory Distress Syndrome (ARDS) has been reported rarely in pheochromocytoma, occurring spontaneously or after therapy with 131I-meta-iodobenzylguanidine (131I-MIBG). Our objective was to determine whether proteinuria is associated with an increased risk of ARDS. This was a retrospective analysis of a prospective cohort study of 64 patients with metastatic pheochromocytoma or paraganglioma treated with 131I-MIBG on institutional protocols. Proteinuria was defined as at least one urinalysis positive for at least trace protein within 1 month prior to 131I-MIBG or within 1 month prior to spontaneous ARDS. Proportions were compared using Fisher's exact test. Urinalyses within the defined time period were available for 48 patients, 8 of whom had proteinuria. Of the 8 patients with proteinuria, 5 developed ARDS: 3 within 10 days following 131I-MIBG, two 6 months following 131I-MIBG. Both patients who developed ARDS 6 months after 131I-MIBG had proteinuria within 1 month before apparently spontaneous ARDS. None of the 40 patients whose urinalyses were all negative for protein developed ARDS. None of the 16 patients with missing urinalyses developed ARDS. Patients with antecedent proteinuria were more likely to develop ARDS than those without proteinuria (63% vs. 0%; p<0.0001). The following variables were not significantly associated with ARDS: 131I-MIBG activities administered, number of 131I-MIBG administrations, age, hypertension, or secretion of catecholamines or metanephrines. In patients with metastatic pheochromocytoma or paraganglioma, proteinuria is associated with ARDS and urine protein should be examined prior to administering 131I-MIBG.     

131I-MIBG therapy in the treatment of pheochromocytoma in children--own experiences

Three cases of pheochromocytoma in children/adolescents or young adults treated by 131I-MIBG are presented in this study. In one patient 131I-MIBG was administrated after ineffective surgical treatment and chemotherapy of a benign retroperitoneal tumor, whereas in two other patients 131I-MIBG therapy was carried out because of malignant pheochromocytoma dissemination. In a child with retroperitoneal paraganglioma decrease of tumor size and its fibrosis after 131I-MIBG therapy allowed radical surgery and complete recovery. In two other cases partial remission was achieved. All patients showed a good subjective response with improvement of the general condition and better blood pressure control. In two children adverse reactions such as leucopenia, hypothyroidism or hypogonadism were observed. The presented data confirm effectiveness and acceptable tolerance of 131I-MIBG treatment in pheochromocytoma, what is very important in pediatric patients.     

The role of [131I]metaiodobenzylguanidine in the treatment of medullary thyroid carcinoma: results in five cases.

Therapeutic doses of [131I]metaiodobenzylguanidine (131I-MIBG) were administered to 5 patients, 3 men and 2 women aged from 33 to 66 years, with proven medullary thyroid carcinoma (one "intermediate" papillary/medullary tumor). The treatment procedure consisted of single doses (3.7-8.5 GBq) of 131I-MIBG given by slow i.v. infusion at 2-8 month intervals. In two advanced-stage patients the treatment played an important palliative role, ranging from an objective response (substantial, but not complete, regression of the tumor) to pain relief which was significant for these patients. In three other cases with residual/recurrent tumor, 131I-MIBG complemented conventional treatment in the attempt to effect a cure which actually was achieved in one case. The only side-effect observed was a transient, mild hematologic toxicity in some cases.     

Preliminary results of [131I]metaiodobenzylguanidine treatment in metastatic carcinoid tumors.

The successful use of [131I]metaiodobenzylguanidine (131I-MIBG) in the scintigraphic localisation and treatment of several tumors deriving from neuroectoderm has led us to its application in metastatic carcinoid tumors. We selected five patients (two men and three women; age range 53-79 years) who showed progression of the disease with severe related symptoms, poor response to traditional therapy and a good uptake of 131I-MIBG in neoplastic tissue. A cumulative radioactivity of 3.7-22.2 GBq was given. All patients had a clear subjective improvement with a better quality of life for a period of 2-36 months, sometimes accompanied by decreased 5-hydroxyindoleacetic acid urinary excretion. Results concerning objective remission of the disease were unsatisfactory. No remarkable early or late side-effect was noted. We believe 131I-MIBG is useful for symptomatic treatment of metastatic carcinoid in seriously ill patients too. Different treatment schedule and recruitment of patients with less advanced disease could make pathological remission a possible goal.     

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.     

Therapy of pheochromocytoma with [131I]metaiodobenzylguanidine.

Fourteen patients with chromaffin tumors were treated with [131]metaiodobenzylguanidine (131I-MIBG); 13 of them suffered from malignant and one from benign pheochromocytoma. In all patients clinical symptoms were improved. In some of these patients tumor shrinkage was observed. In one patient surgery of all tumor tissue was made possible by 131I-MIBG treatment. As shown in one patient, close follow-up is necessary in any case because remnant tumor tissue may start growing again after a long period of rest.     

Preliminary results of [131]metaiodobenzylguanidine treatment in metastatic malignant pheochromocytoma.

The poor results of traditional therapy (for purposes of recovery or palliation) in malignant pheochromocytoma and the well proven uptake of [131I]metaiodobenzylguanidine (131I-MIBG) shown by these tumors, induced us to evaluate the clinical usefulness of radiometabolic therapy with 131I-MIBG. Four patients with malignant pheochromocytoma were subjected to 131I-MIBG therapy, between 1987 and 1991, in our department. They all were in an advanced stage of the disease and showed severe symptoms and poor reaction to traditional therapy. The cumulative activity given was 7.4-22.2 GBq. All patients demonstrated transient subjective improvement; in addition, both biochemical and haemodynamic parameters ameliorated. Two patients showed a reduction in the size and number of metastases seen on scintigraphy. One patient died due to progression of the disease. Three patients are still alive and in good condition. No remarkable early or late side-effects were reported. We suggest that 131I-MIBG radiometabolic therapy in advanced-stage malignant pheochromocytoma could be useful in reducing symptoms. Further investigation might show whether a greater reduction in the size of the tumor could be achieved using different therapeutic schedules or by treating the disease in its earlier stages.     

Radiopharmaceutical therapy of malignant pheochromocytoma with [131I]metaiodobenzylguanidine: results from ten years of experience.

Twenty-eight patients with histologically proven metastatic or invasive, unresectable pheochromocytomas, which were shown to concentrate and retain tracer doses of [131I]metaiodobenzylguanidine (131I-MIBG), were treated with therapeutic quantities of this radiopharmaceutical. Between one and six doses ranging from 97 to 301 mCi (cumulative dose 111-916 mCi) were administered. Partial response in tumor size was achieved in 8/28 patients and partial biochemical responses in 12/28 patients. No pharmacological toxicity was observed. Mild radiation sickness (nausea, vomiting, anorexia) occurred in 21/28. Minor degrees of leukopenia and thrombocytopenia were observed in 3/28. There were three cases of hypothyroidism but no significant hepatic, renal, adrenocortical or autonomic nervous dysfunction. We conclude that therapeutic 131I-MIBG can achieve significant therapeutic responses in some cases of malignant pheochromocytoma without pharmacological toxicity and only mild radiotoxicity.     

Preoperative [131I]metaiodobenzylguanidine therapy of neuroblastoma at diagnosis ("MIBG de novo").

The observed response of [131I]metaiodobenzylguanidine (131I-MIBG) therapy in advanced neuroblastoma after conventional therapy had failed, the noninvasiveness of the procedure, and the high metabolic activity of untreated tumors led to a new protocol to use 131I-MIBG therapy in newly diagnosed patients instead of combination chemotherapy prior to surgery. The objectives of this study are to improve the overall outcome of patients with neuroblastoma by introducing 131I-MIBG therapy as the first therapy in the treatment schedule, in order to reduce the tumor volume, enabling adequate surgical resection and avoiding toxicity and the induction of early drug resistance. The advantages of this approach are that the child's general condition is unaffected before surgical resection is performed and that chemotherapy is reserved to treat minimal residual disease. So far, 13 patients with inoperable neuroblastoma (stage III and IV) were treated with 131I-MIBG initially and then submitted to surgery. More than 50% decrease of the volume of the primary tumor was noted in 7 of 10 evaluable patients; 8 patients have so far been operated with complete resection in 2, greater than 95% resection in 5 and 80% resection in one patient. Three patients are still undergoing 131I-MIBG treatment. The toxicity of 131I-MIBG de novo is in contrast with the previous experience of 131I-MIBG therapy after conventional therapy: only 4 patients had thrombocytopenia and only 1 of 7 patients with bone marrow involvement developed bone marrow depression.(ABSTRACT TRUNCATED AT 250 WORDS)     

131I]metaiodobenzylguanidine therapy in paraganglioma.

Our experience with [131I]metaiodobenzylguanidine (131I-MIBG) therapy in a 10 year old boy is reported. At disease onset, in May 1988, this boy presented a large mass in the upper left abdominal quadrant, which was resected with a histopathological diagnosis of extra-adrenal malignant pheochromocytoma (paraganglioma). He subsequently underwent two further surgical resections and chemotherapy. When 131I-MIBG therapy was started, in June 1990, skeletal and abdominal metastases were present. These localizations were revealed by 131I-MIBG scans and confirmed by x-ray examination. At present 6 courses of therapy have been performed with a cumulative activity of 29.6 GBq. Side-effects have been limited to vomiting and mild thrombocytopenia, lasting 2 weeks during the second course of therapy. After 15 months of therapy, a progressive reduction of MIBG uptake, coupled with a stabilization of the lythic lesions, has been observed.     

Role of [131I]metaiodobenzylguanidine therapy in carcinoids.

From cumulative reported data the sensitivity of [131I]metaiodobenzylguanidine (131I-MIBG) scintigraphy of carcinoids appears to be greater than 60%; at our Institute 131I-MIBG scintigrams were positive in 51 of 70 patients with metastatic carcinoid. Twenty patients with symptomatic, metastatic disease have received 7.4 GBq doses of 131I-MIBG for palliation. Most of these patients had multiple large metastases showing no response to other therapies. No objective response (greater than 50% tumor volume reduction) was ever observed; however, 13 patients were relieved of symptoms, such as flushes, diarrhea, anorexia and pain. Palliation in some of these patients was meaningful and long lasting. Possible explanations for a palliative effect in the absence of objective remission are discussed. Treatment with escalating doses of stable MIBG (up to 80 mg) in 9 patients does not support the hypothesis that the palliation is due to a purely pharmacological effect. Palliation might be explained by the observation that carcinoid liver metastases may present both as hot and cold lesions; 131I-MIBG therapy will thus target exclusively at metabolically active metastases, which are responsible for the patient's symptoms.     

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.     

Summary, conclusions, and future directions of [131I]metaiodobenzylguanidine therapy in the treatment of neural crest tumors.

The role of diagnostic [131I/123I]metaiodobenzylguanidine (*I-MIBG) scintigraphy in the management of pheochromocytoma and neuroblastoma is established, but for other neural crest tumors is less defined. Radiopharmaceutical therapy of all these tumors with large activities of suitably radiolabeled MIBG is a compelling concept. In the five years since the first workshop on 131I-MIBG therapy held in Rome, the initial therapeutic promise appears to have been maintained for neuroblastoma and pheochromocytoma. A significant fraction of patients enter partial remission but complete remission is rare and relapse frequent. To date, experience with other neuroendocrine tumors and the use of 125I in place of 131I remains limited. Many promising areas remain incompletely explored. These include development of appropriate in vitro cultures and animal models, basic pharmacological mechanisms, drug interactions, macro- and microdosimetry and human clinical trials. The latter includes determining dose-limiting toxicity of 131I- and 125I-MIBG, treatment of patients at earlier times or stages of disease, optimal integration with other therapy including granulocyte-stimulating factor and marrow transplant rescue from otherwise limiting myelotoxicity. Progress to date has been slow and painstaking, but nevertheless significant, while the future holds both challenges and promise.     

Results of [131I]metaiodobenzylguanidine therapy administered to three patients with malignant pheochromocytoma.

Three patients with malignant pheochromocytoma were treated with [131I]metaiodobenzylguanidine (131I-MIBG). In two patients with widespread metastatic disease, the effect of treatment was palliative and of short duration. In the third case, with only residual tumor and no metastases, the treatment was effective after 22 GBq of 131I-MIBG.     

131I]metaiodobenzylguanidine therapy in medullary thyroid cancer: Guy's Hospital experience.

[131I]Metaiodobenzylguanidine (131I-MIBG) was utilized in the therapy of seven patients with medullary thyroid cancer. Treatment doses ranged from 3.7 to 11 GBq, for upto four total treatments. Six of the seven patients treated showed some response to treatment (from transient partial response to symptom palliation). Treatment was tolerated well in all patients, with minimal side-effects and no signs of hematologic radiotoxicity. These encouraging results emphasize the potential of 131I-MIBG as a form of targetted radiometabolic therapy in patients with medullary thyroid cancer.     

Role of [131I]metaiodobenzylguanidine therapy in medullary thyroid carcinoma.

In recent years several radiopharmaceuticals have become available, offering new possibilities for the diagnosis and therapy of medullary thyroid carcinoma (MTC). For the diagnosis and follow-up 201TI-chloride and 99mTc(V)-DMSA are the tracers of choice. Imaging with [131I]metaiodobenzylguanidine (131I-MIBG) and 131I-anti-CEA or anti-calcitonin antibodies or fragments is less sensitive but very specific. These tracers can be used to evaluate their potential therapeutic use. Cumulative reported data on the diagnostic use of 131I-MIBG in 178 MTC patients indicate that overall 34.5% of medullary cancers concentrate MIBG. At The Netherlands Cancer Institute 131I-MIBG scintigraphy was positive in 8 of 23 patients with MTC. Four of these patients have received therapeutic amounts of 131I-MIBG, resulting in 1 partial remission and meaningful palliation in 3 patients with metastatic MTC. It is concluded that, although the preliminary experience suggests that the objective response of MTC to 131I-MIBG therapy is limited, the palliation provided to these patients, for whom there is little other treatment, may be very meaningful.     

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)