Endocrine Abstracts

Phaeochromocytomas (Phaeo) and paragangliomas (PGL) are rare catecholamine producing tumours. It can be difficult to predict their malignant potential and patients can sometimes present with metastatic disease many years after their original diagnosis (1). Therefore, we offer a single dose of adjuvant ¹³¹I-Metaiodobenzylguanidine (¹³¹I-MIBG) to subjects felt to be at higher risk of local recurrence (demonstration of capsular or vascular invasion on pathology). However, there is a lack of evidence supporting this practice and concern regarding the safety and tolerability of such therapy. We therefore aimed to review outcomes of cases of adjuvant ¹³¹I-MIBG use in such ‘high risk’ patients.

We reviewed the casenotes of patients who received adjuvant ¹³¹I-MIBG for phaeo or PGL from 1985 to 2010. Patients who had metastatic disease at the time of treatment were excluded. Recurrence of disease was assessed by ¹³¹I-MIBG scintigraphy, computed tomography/magnetic resonance imaging, biochemical measurement of catecholamines and symptom recurrence.

Fifteen patients (eight males) were reviewed. Mean age was 36 years (range 9–79). One patient was receiving an α blocker and another was on β and α blockers during treatment. All had undergone surgical resection prior to ¹³¹I-MIBG therapy. Indications for therapy were capsule breach, local nodal spread/vascular invasion or local recurrence. One patient received ¹³¹I-MIBG due to a strong family history of malignant disease. Each patient received one dose of ¹³¹I-MIBG; mean dose was 9166 MBq (range 5180–10 353 MBq). The treatment was well tolerated with no haematological sequelae. One patient developed recurrent disease and one patient died due to disease progression. Follow-up is ongoing for the rest of the cohort with no evidence of recurrence.

Adjuvant ¹³¹I-MIBG treatment of phaeo/PGL is well tolerated and routine use of α/β blockade during therapy is not required. These data support its use in an adjuvant basis to prevent progression to metastatic disease in patients thought to be at risk of malignant disease however lack of a control group prevents firm conclusions.

Reference

1. Chrisoulidou A et al. The diagnosis and management of malignant phaeochromocytoma and paraganglioma. Endocrine-Related Cancer 2007 14 569–585.