The efficacy of octreotide LAR in acromegalic patients as primary or secondary therapy

Abstract

The objective of this study was to investigate the efficacy of octreotide therapy in acromegalic patients as primary or secondary therapy. Ten acromegalic patients diagnosed at the Endocrinology Clinic in Sarajevo (seven females and three males, mean age 55.2 ± 7.2 years, age range 40-65 years, five patients with microadenoma and five patients with macroadenoma) were treated with octreotide. Among them, 60% of patients were operated on and the majority of the procedures were performed transnasaly (90%). That group of patients had recidivism of disease (pituitary adenoma and acromegaly). The concentration of human growth hormone (HGH) and insulin-like growth factor 1 (IGF-1) was evaluated at 0, 6 and 12 months, while magnetic resonance imaging (MRI) was taken before the treatment and 12 months after. Eight patients received octreotide 30 mg/28 days, one patient received a dose of 20 mg and the other received 60 mg/28 days. Before treatment growth hormone (GH) levels were 50.87 ± 10.56 ng/ml (range: 26-64.9), IGF-1 were 776.66 ± 118.40 ng/ml (range: 526-934). Four patients (40%) were treated with primary octreotide treatment and six patients (60%) with secondary somatostatin analog treatment. At the beginning of therapy, there were no differences in terms of age, HGH levels and IGF-1 levels between primary and secondary treatment groups (p > 0.05). The difference between groups was only in regard to the size of tumors (p = 0.01). After 6 and 12 months the GH levels decreased to 1.61 ± 0.86 ng/ml (range: 0.7-2.65) and 1.85 ± 2.40 ng/ml (range: 0.0-8.3), respectively, while the IGF-1 became 305.90 ± 43.19 ng/ml after 6 months of treatment (range: 240-376) and 256.99 ± 71.43 ng/ml after 12 months of octreotide treatment (range: 126-325), respectively. The pituitary adenomas size prior to treatment was 9.57 mm, while after 12 months of treatment, the size decreased to 8.0 mm. After therapy, a GH decrease to less than 2.5 ng/ml was achieved in 90% of cases; tumor size decrease was achieved in 60% while normalization of IGF-1 was achieved in 100% of the patients, respectively. All differences about HGH and IGF-1 in each group were statistically significant (p < 0.05). In the group of acromegalic patients treated with octreotide LAR as primary therapy, the difference was more significant for GH and IGF-1 than for adenomas size. Octreotide treatment of acromegaly not only decreases GH and IGF-1 concentrations, but also appears to diminish the size of the tumor in about 60% of cases. The somatostatin analogs are more efficient in the primary treatment of acromegalic patients, due to the fact that primary therapy is as effective as secondary therapy but primary therapy has small advantages when compared with secondary octreotide therapy because no surgical treatment is required before.