The efficacy of octreotide LAR (long acting release) treatment in patients with somatotropinoma, and mixed pituitary tumours.

Objective: The efficacy of somatostatin analogues in the treatment of acromegaly is not always equal and therefore we wanted to evaluate the efficacy of therapy with octreotide long acting release (LAR) in patients with monohormonal tumours (somatotropinomas) in comparison to individuals with mixed pituitary tumours secreting alpha-subunit.

Method: The 35 acromegalic patients (18 males and 17 females), aged 41.8 +/- 8.8 years, were divided into 2 groups according to the secreted hormones: 1 with mixed pituitary tumours with elevated growth hormone and alpha-subunit concentrations, the other with isolated growth hormone hypersecretion and normal alpha-subunit levels. The groups included 19 patients (9 males and 10 females), aged 40.1 +/- 7.1 years (mean +/- SD), and 16 patients (9 males and 7 females) aged 43.8 +/- 8.8 years (mean +/- SD), respectively.

Results: The decrease of GH and IGF-I levels after octreotide LAR treatment were observed in both groups. However, the reduction of GH and IGF-I concentrations was not equal in both groups and the differences between both groups were statistically significant (P = 0.01 for GH levels, and P = 0.047 for IGF-I levels).

Conclusions: After octreotide LAR treatment, the decrease of GH level and of mean IGF-I values was greater in patients with mixed pituitary tumours and high alpha-subunit concentrations than in patients with isolated GH hypersecretion and normal alpha-subunit levels.