Endocrine Abstracts

Introduction: Although acromegaly and pituitary gigantism have the same pathological cause, they have different disease characteristics.

Aim: To study tumour size, treatment course and the most common comorbidities in a population with young-onset acromegaly.

Materials and Methods: UK Acromegaly Register (UKAR, 22 centres, 1997-2017) retrospective analysis, enriched with patients from the FIPA-consortium. We defined gigantism as diagnosis of GH excess at <20yrs, or +3SD height for UK population. We recruited 156 giants: 111 from 3309 UKAR patients, and 90 from FIPA-consortium (45 overlapping). The remaining cohort from UKAR formed acromegaly control group (AG).

Results: Giants had pituitary macroadenoma and extrasellar extension more often than AG (84.9% vs 68.8%, P = 0 .001 and 53.2% vs 33.9%, P < 0.001). Most patients underwent surgery (giants:87.4%, AG:83.9%%). Giants had repeated surgery and transcranial surgery more often than AG (27.8% vs 9.0%, P < 0.001 and 11.9% vs 4.2%, P < 0.001). There was no difference in radiotherapy (59.1% vs 58.8%). Medical treatment was comparable for dopamine agonist (34.8% vs 37.8%, P = 0 .456), and pegvisomant (10.3% vs 7.2%, P = 0 .148), but higher for somatostatin analogues in giants (53.5% vs 44.6%, P = 0 .028). The total number of treatment modalities was higher for giants (2.88± 1.52 vs 2.49± 1.38, P = 0 .003). Polyps/cancers in colonoscopy and hypertension were more frequent in acromegalics in age adjusted analysis (25.4% vs 42.1% P = 0 .008 and 24.5% vs 52.3%, P < 0.001). Diabetes does not have higher frequency in acromegaly (32.7% vs 28.3%, P = 0 .280). Death rate in giants was lower than acromegalics (12.8% vs 19.5%, P = 0 .038), but with lower age of death in giants (64.9 vs 73.48yrs, P = 0 .006). From the genetically screened giants (59.6% of cases), 41.9% harboured an AIP mutation.

Conclusions: Pituitary gigantism patients more frequently have extrasellar macroadenoma, and require more invasive treatment (re-surgery, transcranial approach, more medical treatment, more overall treatment modalities). Comparison of morbidity, mortality and GH/IGF-1 control adjusted for decades are further needed in these patients. On behalf of the UK Acromegaly Register Study Group 2019 and the FIPA-consortium UK members