SOMATOSTATIN RECEPTOR SCINTIGRAPHY AND OCTREOTIDE TREATMENT IN PATIENTS WITH THYROID EYE DISEASE

OBJECTIVE Octreotide, a potent long-acting synthetic somatostatin anal ogue, has been reported to have a beneficial effect in thyroid eye dis ease (TED), but the precise mechanism of action remains unexplained. I n-111-DTPA-D-Phe(1)-octreotide (Octreoscan-111) has been used to local ize a number of endocrine tumours and visualize somatostatin receptors in the retrobulbar tissue of patients with TED. Furthermore, this tec hnique can predict the inhibitory effect of octreotide on hormone secr etion by endocrine tumours, as there is a close relation between the c linically observed inhibition and visualization of the tumour using Oc treascan-111. The aims of the present study were to confirm the benefi cial effect of octreotide in patients with TED, to investigate the pre sence of somatostatin receptors in the orbital area and also, if possi ble, to ascertain whether this technique could select those patients w ith TED who might benefit from treatment with octreotide. DESIGN A pro spective study. SETTING An endocrine clinic of a national hospital. PA TIENTS Twenty treated thyrotoxic patients with TED, 5 treated thyrotox ic patients without TED and 5 normal individuals were studied. In 12 p atients with TED, 5 without TED and 5 normal individuals, Octreoscan-1 11 scintigraphy of the orbits was performed. The remaining 8 patients with ophthalmopathy served as controls. In patients with TED who were investigated with Octreoscan-111, 300 mu g octreotide daily was given for 12 weeks. RESULTS Six patients in both eyes and one patient in one eye showed an improvement in ocular manifestations as assessed by cli nical criteria and changes in the NOSPECS score, while the rest showed no improvement. The patients who showed an improvement had a high num ber of somatostatin receptors and positive orbital scans, while with o ne exception the patients who did not respond had a low number of rece ptors and negative orbital scans (P < 0.02). None of the, 5 patients w ithout TED nor the normal individuals had a positive orbital scan. Sev en out of 8 control patients with TED showed no change in the disease during the trial, while 1 deteriorated. CONCLUSIONS We conclude that o ctreotide has a beneficial effect in thyroid eye disease and that Octr eoscan-111 could predict those patients with thyroid eye disease who m ight benefit from this treatment.