[Somatostatin receptor status in non-medullary thyroid carcinoma]. / Untersuchungen zum Somatostatinrezeptor-Status bei nicht-medullären Schilddrüsenkarzinomen.

ABSTRACT

AIM: Recent in-vitro and in-vivo studies demonstrated a somatostatin receptor expression in some non-medullary thyroid carcinomas. In this study we investigated the somatostatin receptor status for this particular tumor entity in a larger patient group. SUBJECT AND METHODS: We compared 131-iodine with 111-In-pentetreotide scans in 24 patients with metastasizing, non-medullary thyroid cancer. The findings were correlated with other imaging modalities. Additionally, we performed receptor autoradiography in one patient, octreotide therapy in another patient and administration of 90-Y- and 111-In-DOTATOC in 2 consecutive patients. RESULTS: In the 15 patients with papillary or follicular carcinoma, 111-In-pentetreotide was inferior to 131-I in 8/15, equal in 1/15, and superior in 6/15 patients. In 8/9 of the patients with Hürthle cell carcinoma, metastases showed a 111-In-pentetreotide accumulation of various intensity, while 131-iodine scans were negative except for one patient. 111-In-pentetreotide was equal or superior compared to 201-Tl or 99m-Tc-sestamibi, but for the most part inferior in comparison with 18-F-FDG-PET. The findings of 111-In-pentetreotide scintigraphy correlated well with the receptor autoradiography and the accumulation of DOTATOC, but not with the therapeutic effect of "cold" octreotide on the thyroid cancer metastases. CONCLUSIONS: Several metastases of papillary and follicular carcinoma, and the majority of Hürthle cell cancer metastases can express somatostatin receptors. 111-In-pentetreotide scintigraphy is a promising tool for localization of metastases especially in Hürthle cell cancer or if PET is not available, and may be useful for selection of possible candidates, if therapeutic effective beta-emitting somatostatin analogues will be available for routine application.