Primary treatment of acromegaly with octreotide LAR: a long-term (up to nine years) prospective study of its efficacy in the control of disease activity and tumor shrinkage

Context: Neurosurgery is regarded as the first-line treatment of acromegaly. Because of its low cure rate in macro and invasive adenoma, the role of primary medical treatment is debated. Objective: Our objective was to evaluate primary pharmacological treatment in acromegaly. Design and Setting: We conducted an open prospective study at two Italian tertiary level centers. Patients: We studied 67 consecutive patients ( 36 women; age, 54.9 +/- 14.2 yr; 72% bearing macroadenoma). Intervention: Individually tailored octreotide LAR (OCLAR) was administered. Main Outcome Measures: Outcomes included safe GH ( < 2.5 mu g/ liter), normal age-matched IGF-I levels, and tumor shrinkage. Results: After a median follow-up of 48 months ( range, 6 - 108 months), safe GH levels and normal age-matched IGF-I values were obtained by 68.7 and 70.1% of patients, respectively. Hormonal endpoints were achieved regardless of basal levels, and early results were predictive of outcome. Tumor shrank in 82.1% of patients by 62 +/- 31% ( range, 0 - 100%), decreasing from 2101 +/- 2912 to 1010 +/- 2196 mm(3) ( P < 0.0001). The higher the basal GH values and the greater the GH/IGF-I changes on treatment, the greater the tumor shrinkage. Tumor disappeared in three patients and was progressively reduced to empty sella in five patients; apparent magnetic resonance imaging cavernous sinus invasion disappeared in three. In males, testosterone increased, restoring eugonadism in 64% of hypogonadal patients. Conclusions: The efficacy on GH/IGF-I levels in unselected patients and the outstanding volumetric control indicate that treatment with OCLAR may be the first therapeutic approach to all acromegalic patients not amenable to surgical cure. Tumor shrinkage might also encourage the evaluation of primary OCLAR adoption in patients with initial visual field defects.