Endocrine Abstracts

Background: Pituitary radiotherapy (RT) is known to have metabolic, cardiovascular and cerebrovascular complications due to the effects of radiation on normal pituitary tissue and surrounding neurological structures.

Objectives: Retrospective evaluation of effects of RT on pituitary dysfunction, type 2 diabetes mellitus, cardio- and cerebrovascular morbidity and mortality in unselected consecutive pituitary adenomas in a tertiary centre.

Methodology: Retrospective case note and electronic record review of 124 consecutive pituitary adenomas (Non-functioning adenomas {NFA}-57, acromegaly-33, prolactinoma-8, cushings-6, others-6) subjected to RT from 1968 to 2015 was undertaken. Age Standardised Mortality Ratio (ASMR) was calculated in comparison with mortality rates of Leicestershire population as per Office of National Statistics (ONS).

Results: n=124 (68 males, 56 females), mean age 45 yrs, mean duration of follow-up post-RT 16.2 yrs. 53% of functional tumours achieved remission (25/47). Hypopituitarism increased from 39% pre-RT (48/124) to 81% (100/124) by the end of follow-up period. An increased prevalence of ischaemic heart disease (IHD)(7 to 11), myocardial infarction (1 to 5), stroke (1 to 12), heart failure (1 to 9), dementia (1 to 6) was noted from pre-RT to end of follow-up period. There was an approximate 5-fold increased incidence of diabetes (6 to 29), and one new diagnosis of tumour (meningioma). Acromegaly patients showed higher IHD incidence than NFA (16% vs 10%); NFA showed higher stroke incidence than acromegaly (14% vs 3%) . ASMR was 8113/100,000 (CI 5345 – 10882 deaths per 100,000 population) for RT versus ASMR for Leicestershire 1174/100,000 (reported from ONS), yielding a Relative Risk of 6.9.

Conclusion: RT-induced-hypopituitarism occurs in the majority of patients. RT appears to increase the incidence of diabetes; stroke, cardiac disease and dementia. In post-RT patients, ASMR is ≃7 times higher than the background population. These data suggests a conservative approach to pituitary RT should be considered in order to prevent long term morbidity and mortality.