Endocrine Abstracts

Background: Adrenal incidentalomas are common and require investigation to exclude malignancy and evidence of hormone overproduction. Prospective screening programmes are essential for early detection of cancer but often lead to incidental findings which have potential health economic implications and may increase patient anxiety. With regards to investigation of incidental adrenal nodules, current national lung cancer screening recommendations are not in keeping with current endocrinogy guidelines regarding which nodules need further investigation. This study aimed to assess the characteristics of the patients identfied with adrenal nodules from the UK Regional Lung Cancer Screening trial.

Methods: Data were collected retrospectively on patients over a three year period. Inclusion criiteria were adult patients who had undergone a computerised-tomography scan as part of the lung cancer screening trial with an adrenal nodule >1cm incidentally identified. Demographics, imaging characterisitics (maximum axial diameter, Hounsfield Units - HU), biochemistry and outcome data were recorded.

Results: A total of 187 patients were included (55% male), mean age 69.8 years±7 (SD). 145 (77%) had a unilateral lesion, mean size of 2.3±0.9cm. 17(9%) lesions were >4cm and 26(14%) had HU above 10. Overall 183 (98%) of the cohort underwent associated functional hormone tests, 94 (51%) had cortisol >50nmol/l on overnight dexamethasone suppression test. Of those who had plasma metanephrines, two (1%) were signifiantly elevated and 5(5%) had aldosterone:renin suggesting possible primary hyperaldosteronism (PA). Following review in the Adrenal MDT one patient was diagnosed with phaeochromocytoma and 2 with Conn’s syndrome. 59 patients were diagnosed with mild autonomous cortisol secretion (MACS). Of the patients with MACS, 49 had further investigations; 13(27%) had pre-diabetes, 7(14%) had hypertension and 2(4%) had osteoporosis identified. Three patients underwent surgery. If the lung screening guidelines had been followed only 17(9%) patients would have been referred to the adrenal team and 52 of the patients with MACS would not have undergone further investigation.

Conclusions: Amongst this cohort of patients, a majority had postive functional testing requiring further review. Although this has an impact on resources, important diagnoses were made as a result, including phaeochromocytoma, PA and MACS. Additionally, further co-morbidities assoicated with MACS including pre-diabetes and hypertension were identified allowing earlier intervention. Based on these data, 91% of investigated lesions would not have warranted further evaluation if the national lung cancer referral recommendations had been followed. This analysis highlights the additional diagnoses that would have resulted from investigating all adrenal nodules greater than 1cm in diameter.