Effectiveness of long-acting octreotide in suppressing hormonogenesis and tumor growth in thyrotropin-secreting pituitary adenomas: report of two cases.

ABSTRACT

BACKGROUND: The subcutaneous (s.c.) administration of somatostatin analogs, such as octreotide acetate (SMS) and lanreotide, in patients with thyrotropin (TSH)-secreting pituitary adenomas (TSPA's)--thyrotropinomas with residual tumor after initial surgical therapy is effective in controlling hyperthyroidism, as well as curtailing tumor growth in the majority of patients. Long-acting preparations of the above agents, i.e. SMS-LAR and lanreotide-SR, have been synthesized and can be administered as depot injections intramuscularly (i.m.) at intervals of several weeks. Recent studies have reported on preliminary data regarding the use of such preparations in patients with TSPA's. MATERIALS AND METHODS: We present two cases of TSPA's with residual tumor following transsphenoidal adenomectomy. Neither of the two patients underwent external beam pituitary irradiation. The presence and extent of tumoral TSH hypersecretion was assessed by standard biochemical and dynamic endocrine testing, while tumor size was evaluated by conventional radiographic techniques. RESULTS: In both patients, TSH secretion was effectively suppressed by SMS-LAR. Moreover, administration of this compound halted further tumor growth, as well as resulted in improved patient comfort, for 12 and 10 months respectively. CONCLUSION: Our date corroborate earlier reports on the usefulness of SMS-LAR in the medical management of patients with TSPA's who have residual disease after initial pituitary surgery and/or irradiation.