PSUN21 Adrenal Incidentaloma: Is Interval Scanning Warranted?

BACKGROUND: Adrenal incidentaloma (AI) is an increasingly recognised finding, with pressure on healthcare systems. Earlier guidelines recommended interval scanning and testing to ensure stability. However, the recent European guidelines do not recommend the need for repeat scanning if initial assessment is reassuring. AIM: To explore the utility of this guidance on need for interval scanning of benign AI. METHODS: A retrospective unselected review of AI cases seen in our unit before the launch of the European guidelines was conducted. At that time, a local protocol was in use to characterise scan and test adrenal functions at baseline, and at two years, the scan and endocrine tests were repeated. We compared the baseline scan results with those at two-years. RESULTS: We collected data on 54 patients initially identified between 2011 and 2016. Of these, 31 had left-sided lesions, 15 had right-sided lesions and 8 bilateral. Of the left-sided lesions, 16 increased in size over the 2.2-year follow-up period, 4 decreased in size and 17 remained the same. Of the right-sided lesions, 3 increased in size over the follow-up period, 6 decreased in size and 13 remained the same. Of those that increased (left- or right-sided), the largest increase was 5mm. Taking 2 mm as the cut-off for a significant change: on the left, 32/37 (86%) had a change ≤2mm (P<0. 001 for no increase). On the right, 21/22 (95%) had a change ≤2mm (P<0. 001). Using a ≤5% increase as cut-off: 28/37 on the left (P=0. 028) and 20/22 on the right (p<. 001) showed ≤5% increase. There was no statistical difference in change in lesion size in terms of laterality, being indeterminate on initial scanning, gender, age or initial size on presentation. CONCLUSION: We found that there was no significant change in size after two years. Therefore, our data support the European guidelines that repeat scanning is unnecessary. This should be reassuring to patients and provide a more cost-effective service. Presentation: Sunday, June 12, 2022 12:30 p.m. - 2:30 p.m.