Endocrine Abstracts

Objective: The rate of surgical cure of acromegaly with transphenoidal hypophysectomy varies greatly. Factors that have been previously noted to affect outcome include tumour size and level of growth hormone (GH). We evaluated clinical factors associated with surgical outcome in our patient series.

Method: Retrospective study of clinical data and surgical outcome of patients who underwent transphenoidal hypophysectomy for acromegaly by a single surgeon at a tertiary neurosurgical centre.

Result: Clinical and outcome data was obtained on 61 patients. Cure was defined as either a nadir GH <2 mU/l following a glucose tolerance test or mean GH of <5 mU/l post-operatively. Cure rate was 50% overall (89% for microadenomas, 33% for macroadenomas). Histological analysis revealed 16 were pure GH adenomas, 30 immunostained for GH and prolactin (PRL), and 11 immunostained for >2 hormones (GH, PRL plus TSH, LH and/or FSH). Pre-operative GH levels of <=20 mU/l (12 cases) were associated with good cure rates (Macroadenoma 88%, Overall 92%). None of the 9 cases with GH >100 mU/l were cured. PRL was elevated (>600 miU/l) in 13 cases, 11 involving adenomas immunostaining for PRL. An elevated PRL was associated with a lower cure rate (23%). Macroadenomas with elevated PRL had a cure rate of 17% compared to 50% with normal PRL. Taking GH levels into account, cases with elevated PRL had poor outcome regardless of GH.

Conclusion: High pre-operative GH levels were associated with poor outcome, cure being unlikely with GH levels >100 mU/l. Our data suggests elevated PRL may be associated with poor outcome independent of GH levels.