Transsphenoidal surgery is the first-line therapy for patients with acromegaly, but can achieve biochemical control with normalization of somatomedin C in 40-80% of cases. All patients with continued growth hormone hypersecretion after neurosurgery require adjunctive therapy to prevent morbidity and premature mortality. The aim of our study was to evaluate the efficacy of long-acting somatostatin analog--octreotide LAR (OCT-LAR) as adjunctive therapy for patients with persistent disease. 14 adult subjects (age 45 +/- 15 years) were included into the study. All patients were diagnosed as having growth hormone secreting pituitary tumor and underwent transsphenoidal surgery (TSS). Radiotherapy (RT) was used as adjunctive therapy in 7 of investigated persons. In all subjects elevated level of somatomedin C was found, 9 have increased level of growth hormone (hGH) as well. After 6 months therapy with OCT-LAR we noticed drop in somatomedin C and hGH levels in all patients. Mean drop in somatomedin C level was 42.3% (p=0.001), in GH level was 52.3% (p=0.001). We found entire normalization of GH in 12 (85.7%) patients, nearly normalization of somatomedin C (level lower than 110% of normal upper limit) in 8 (57%) patients. We found no significant correlation between decrease in somatomedin C and its level prior to the treatment (p=0.8), but high positive correlation between decrease in hGh level and its initial value (R=0.75, p=0.002). Decreases in both somatomedin C (p=0.7) and hGH (p=0.6) levels were not correlated with patients' age. The therapeutic outcome defined as decrease in somatomedin C level was not significantly different between patients with or without adjunctive radiotherapy in the past (p=0.08) and between patients with intensive or weak isotope collection in the pituitary in 99mTc-octreotide scintiscan (p=0.2).
Conclusions: Octreotide-LAR efficiently reduces somatomedin C and GH levels in patients with active acromegaly. Initial values of somatomedin C as well as age and isotopic imaging findings are not valuable predictor factors for therapeutic outcome.