Endocrine Abstracts

Introduction: Low-grade gliomas (LGGs) are the commonest benign childhood brain tumour and typically affect the optic pathway and diencephalon, thus potentially causing serious neuroendocrine deficits from tumour and/or treatment. We have previously presented a preliminary analysis of risk factors for neuroendocrine morbidity in our 30-year cohort of LGG patients at Great Ormond Street Hospital, and now present comprehensive results of the completed dataset.

Methods: Retrospective case note analysis of 166 patients with optic pathway and diencephalic LGGs diagnosed between 1980–2010 by multivariate regression.

Results: Patients were of median age 4.90 (range 0.18–15.37) years at diagnosis, and followed up for a median of 8.21 (0.04–29.70) years. 30-year overall, progression-free and endocrine event-free survival (EEFS) were 84.9, 49.0 and 20.8% respectively. EEFS continued to fall up to 15 years from diagnosis, being independently reduced by hypothalamic involvement (P=0.00), more recent treatment era (P=0.00) and radiotherapy (P=0.02). The number of deficits was increased by hypothalamic involvement (P=0.02), repeated surgery (P=0.03) and radiotherapy (P=0.04). GH deficiency was commonest (41.0%), followed by precocious puberty (26.6%), LH/FSH deficiency (20.4%), ACTH deficiency (14.5%), TSH deficiency (13.9%), posterior pituitary dysfunction (13.3%) and hyperprolactinaemia (10.8%). Posterior pituitary dysfunction occurred despite minor surgical interventions (17/29 events were post-shunt/ biopsy procedures), and was present at death in 6/10 patients. 32.5% were obese at last follow-up, particularly with more recent treatment strategies (P=0.03) and hypothalamic tumours (P=0.04).

Conclusion: This large long-term multivariate analysis of LGG survivors strongly suggests that hypothalamic involvement is more predictive of both the onset and severity of endocrinopathies than irradiation, and challenges the perception that surgery is less neurotoxic, as even minor, repeated surgical intervention can result in increased endocrinopathies and fatal posterior pituitary dysfunction. More recent treatment strategies have not increased overall survival in this cohort, at the expense of increasing the risk of earlier endocrinopathy and obesity.