Endocrine Abstracts

Purpose: Lutetium-177 Dotatate peptide receptor radionuclide therapy (PRRT) is an established option for advanced neuroendocrine tumours (NETs). The NETTER-1 trial demonstrated clear progression-free survival (PFS) and overall survival (OS) advantage in midgut NETs, while the NETTER-2 study suggests potential benefit from earlier use of PRRT in higher-grade disease. However, trial populations often exclude many patients seen in routine practice. Real-world evidence across larger, unselected UK populations is therefore essential to confirm outcomes and inform clinical decision-making. We present OS and PFS outcomes from one of the largest UK single-centre PRRT audits to date.

Methods: Data was collected from 138 patients with well-differentiated, unresectable/metastatic gastroenteropancreatic NETs who received Lutetium-177 Dotatate between August 2018 and June 2025 in the North East and North Cumbria. Baseline demographics, tumour grade and primary site of disease were collected. OS and PFS were measured from PRRT initiation using Kaplan–Meier analysis.

Results: A total of 138 patients were included (36 grade 1, 102 grade 2). Median OS for the population was 51.8 months (Figure 1). Median OS was not reached for grade 1 (58.3% alive at 52.3 months). Grade 2 had a median OS of 49.2 months (Figure 2). Median PFS for the population was 45.2 months (Figure 3). For grade 1, median PFS was not reached (55.4% without progression at 45.2 months). Grade 2 had a median PFS of 35.6 months (Figure 4). A total of 103 (74.6%) had gastrointestinal primaries and 35 (25.4%) had pancreatic primaries, with no significant survival differences between groups. Twenty (14.5%) discontinued treatment: 5 due to progression, 5 haematological toxicity (2 pancytopenia, 3 thrombocytopenia), 3 renal toxicity, 2 gastrointestinal toxicity (diarrhoea, enteropathy), 3 reduced fitness, and 2 patient-related factors (relocation, non-compliance).

Conclusion: This large regional dataset demonstrates that Lutetium-177 Dotatate achieves survival outcomes in routine UK practice mirroring those seen in clinical trials. These results provide reassurance that PRRT is safe and effective in the NICE-approved patient population. As new trials such as NETTER-2 explore earlier integration of PRRT, our findings provide an essential benchmark of outcomes under current NICE-approved pathways, reinforcing its safety and efficacy across unselected patients.