Endocrine Abstracts

Objective: To evaluate whether serum GH and IGF1 levels achieved after 3 months treatment with somatostatin analogues (SSA) are concordant with the efficacy of SSA after longer treatment with the same dose.

Patients and methods: From 71 patients with acromegaly treated with SSA in our clinic, in 38 of them (28 women, 10 men, aged 22–62 years) data on serum GH and IGF1 were available at baseline, after 3 months and at the last evaluation on the same SSA dose. Two patients have been evaluated on two different doses of SSA. Optimal response to SSA included random GH ≤2.5 ng/ml and normal age-adjusted IGF1 level.

Results: From 40 evaluations, 18 were on octreotide LAR (9 on 20 mg, 9 on 30 mg/month) and 22 were on lanreotide SR (15 on 60 mg/month, 7 in 90 or 120 mg/month). Three evaluations were before neurosurgery and 25 patients had pituitary radiotherapy before SSA. Mean duration of treatment was 14±9.5 months (5–44).

Normal random GH was recorded at 3 months in 21/39 patients (53.8%) and at the last evaluation in 24/39 patients (61%). Concordant values between the two points of evaluation were found in 28/39 patients (71.8%). Mean±S.D. GH values were 6.1±9.8 and 5.7±11.9 ng/ml respectively (P=NS). Normal serum IGF1 was recorded at 3 months in 20/35 patients (57.1%) and at the last evaluation in 17/35 patients (48.5%), concordant values in 31/35 patients (88.5%). Mean IGF1 levels (×ULN) were 1.3±0.82 and 1.3±0.84 respectively. Normal values at 3 months and elevated at the last evaluation were found for GH in 4/39 patients (10%) and for IGF1 in 4/35 patients (11.4%, 3 of them up to 1.3×ULN). Normalization only at the last evaluation was recorded in 7/39 patients (18%) for GH.

Conclusion: In patients with acromegaly the response to somatostatin analogues evaluated at 3 months was concordant with the response after longer treatment with the same dose in about 72% of patients for GH and 89% for IGF1. When discordances between normal IGF1 and elevated random GH occur at 3 months, we suggest re-evaluation on the same SSA dose.