Endocrine Abstracts

The current paradigm for management of acromegaly includes surgery as primary treatment regardless of whether or not this is likely to be curative. There is increasing evidence that somatostatin analogue medical therapy may produce shrinkage of growth hormone producing pituitary tumours. This study tests the hypothesis that primary medical therapy may produce clinically significant tumour shrinkage prior to surgery.

Eleven treatment naïve subjects with acromegaly were recruited. Mean GH 51 mU/l (range 6–96), mean IGF1 99 nmol/l (range 54–161). Maximum tumour diameter at presentation 12–38 mm. All patients were treated with lanreotide autogel at maximum dose. Nine subjects completed 12 months treatment. Mean GH fell to 14 mU/l (2.5–37.8). Mean IGF1 fell to 71 nmol/l (17–150). Tumour shrinkage was seen in 9 subjects with a mean reduction of 31.1% (17.1–57.6%). Although the fall in IGF1 appeared to plateau by 6 months we continued to see tumour shrinkage to the end of the study. None of the pre-study measures predicted the degree of tumour shrinkage. We did not see significant shrinkage beyond 6 months unless we had already seen tumour shrinkage at the 6 month scan. Two individuals withdrew because of lack of response to therapy and underwent surgery before trial completion.

In conclusion primary somatostatin analogue therapy may be an effective but unpredictable primary treatment of acromegaly. A 6-month scan may be used as an assessment for whether to continue treatment.