Brain Tumors Research Today is a free monthly online journal that collates and summarizes the latest research about Brain Tumors, including details on symptoms, benign and malignant tumors, gliomas, screening, treatment.

The implication of somatotroph adenoma phenotype to somatostatin analog responsiveness in acromegaly.

Bhayana S, Booth GL, Asa SL, Kovacs K, Ezzat S

Department of Medicine, Mount Sinai Hospital, 600 University Avenue, Room 437, Toronto, Ontario, Canada M5G 1X5.

CONTEXT: Persistently elevated GH and IGF-I levels are associated with increased mortality. Their response to somatostatin analogs (SSA) is variable. OBJECTIVE: The objective of this study was to examine the significance of somatotroph adenoma type on response to SSA. DESIGN: This study was a retrospective examination of postoperatively treated acromegalic patients with the SSA octreotide. SETTING: The study was performed at a university-affiliated tertiary care center. Patients: Forty patients with acromegaly were studied. MAIN OUTCOME MEASURES: Normalization of IGF-I levels and GH responses were the main outcome measures. RESULTS: Univariate analysis revealed that responders were more likely to have densely granulated somatotroph adenomas (80% vs. 43.8%; P = 0.024), to be older (51.3 vs. 38.2 yr; P < 0.003), to have smaller tumors (stage < or =3; 78.6% vs. 35.7%; P = 0.022), to have lower baseline IGF-I (453 vs. 716 microg/liter; P < 0.001) and GH levels (2.7 vs. 7.8 microg/liter; P < 0.05), and to require a lower maximum dose of SSA (24 vs. 31 mg every 4 wk; P = 0.013). Multivariate analysis confirmed that a densely granulated adenoma was the strongest predictor of complete response [adjusted odds ratio (OR), 58.41; 95% confidence interval (CI), 1.24-1000.00; P = 0.04] compared with other covariates, including older age at time of diagnosis (OR, 1.15/yr; 95% CI, 1.01-1.31; P = 0.03), and tumor stage of 3 or less (OR, 29.77; 95% CI, 1.01-885.45; P < 0.05). CONCLUSIONS: Somatotroph tumor type represents a strong clinical predictor of response to SSA treatment and will help to identify patients who warrant more vigilant management of their disease.

Published 8 November 2005 in J Clin Endocrinol Metab, 90(11): 6290-5.
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