Which of the following statement(s) is/are true with respect to growth hormone secreting pituitary adenomas?

c. Over 80% of growth hormone-secreting microadenomas can be cured with transphenoidal resection

d. Preoperative treatment of macroadenomas with a somatostatin analogue may improve postoperative remission rates

The endocrine diagnosis of acromegaly rests largely on serum growth hormone (GH) levels, because 90% of patients will have levels over 10ng/mL. When acromegaly is apparent but consistently elevated growth hormone levels are not obtained, the glucose suppression test is the most useful diagnostic procedure. In normal patients, 1 to 2 hours after the oral administration of 100 g of glucose, the growth hormone level falls well below 5 ng/mL. This suppression is not seen with GH-secreting adenomas, and often a paradoxical rise in GH is observed.

The goals of treatment are to lower the circulating growth hormone or somatomedin C levels to within a normal range and to reduce the size of the mass lesion causing compression-related symptoms. When a microadenoma is removed transsphenoidally, endocrine remission may be expected in 80% to 88% of cases. When a macroadenoma is resected, postoperative remission is reported in 30% to 68% of cases. The rate of remission is inversely related to preoperative GH levels and tumor size. Preoperative treatment of macroadenomas with a somatostatin analogue may improve postoperative remission rates.