Background: Although mostly benign, head and neck paragangliomas require active management because of injury to adjacent neurovascular structures. Surgery, usually preceded by embolization, allows for complete tumor removal. However, surgery carries a significant risk of iatrogenic injury, related to tumor volume. Because paragangliomas express somatostatin receptors with high density, we investigated the effect of a long-acting somatostatin analogue (OCT-LAR) on the size of such tumors to reduce iatrogenic injury and related the percentage of tumor shrinkage to a tracer uptake index calculated on somatostatin receptor scintigraphy (SRS).
Methods: In eight of the first nine patients, 30 mg of OCT-LAR was given intramuscularly every 28 days for 3 doses; one patient withdrew after the first dose because of side effects. Conventional imaging with computed tomography (CT) scan or magnetic resonance imaging plus SRS revealed 18 paraganglioma sites. For each lesion, a tracer uptake index was calculated on pretreatment SRS. All 18 tumors were measured by CT scan before treatment and 1 month after the third injection.
Results: The average percent tumor shrinkage was 4.0 +/- 10.0%, and the average tumor reduction was 1.0 +/- 3.8 cm (P = .27, NS). Only 2 of the 18 paragangliomas shrank by more than 20%; these two tumors belonged to the only one secreting patient. There was no significant relation between tracer uptake index and tumor response.
Conclusion: These results suggest 1) that SRS results do not predict OCT-LAR efficacy on paraganglioma size, and 2) OCT-LAR is not useful in the preoperative management of paragangliomas.