Octreotide treatment does not affect the size of most non-functioning pituitary adenomas.

The somatostatin analogue, octreotide (OC) has commonly been used in the management of growth hormone- and thyrotropin-secreting pituitary tumors, and shown to be effective both on hormone production and tumor size. Because OC receptors may be expressed also in some nonfunctioning pituitary adenomas, it has been postulated that OC might play a role in the treatment of these tumors as well. In the present study, the morphological effects of OC administration, as assessed by computer tomography (CT) scan, were evaluated in 8 patients (5 men, 3 women, age range 25-79 yr) affected by non-functioning pituitary tumors. The drug was given sc at the dose of 100 micrograms tid for 3-6 months. No significant change in visual field or tumor size occurred after OC treatment in 7 patients, whereas one showed a significant improvement of visual field associated with a decreased tumoral mass. These data suggest that OC is not an effective drug in the management of nonfunctioning pituitary adenomas.