Objective: To evaluate the efficacy of octreotide in the treatment of pituitary thyroid-stimulating hormone (TSH)-secreting adenomas.
Data Sources: Combination of review and original data. Review data included information supplied by Sandoz Pharmaceuticals from patient case report forms and information from abstracts and articles published in the French or English language between 1987 and 1991. Original data included follow-up data on 15 of 37 previously reported cases and data on 15 new cases provided by 11 investigators.
Study Selection: Fifty-two cases from 24 medical centers in nine countries reported between 1987 and 1991.
Data Extraction: Chief clinical characteristics of the patients; dose and duration of octreotide treatment; serum TSH, thyroid hormone, and free -subunit levels before and during treatment; serial anatomic evaluation of the pituitary gland by either computed tomographic scanning or magnetic resonance imaging; and side effects.
Data Synthesis: After the first octreotide dose (50 to 100 g), TSH levels decreased in all but 2 patients (mean decrease for the whole group, 55.8% 27%). Levels of -subunit decreased in 15 of the 19 patients who had -subunit assessments (mean decrease, 37.5% 24%). Reduction of TSH levels after short-term treatment (50 or 100 g two or three times daily) was observed in 30 of 33 patients (mean decrease, 74.1%). Thyroid hormone levels were reduced in all patients and returned to normal in 73%. Despite an initial response to therapy, thyroid hormone levels continued to rise (true escape) in 2 patients receiving short-term therapy and in 3 patients receiving long-term therapy. Partial shrinkage of the adenoma occurred in 11 patients.
Conclusions: Octreotide is an effective treatment for TSH-secreting adenomas. Thyroid-stimulating hormone levels almost always decreased, and thyroid hormone levels reverted to normal in about three quarters of patients. Partial tumor shrinkage was observed in one third of patients receiving long-term octreotide treatment.