Abstract 219P
Background
PRRT with LU has shown promising results in the management of patients (pts) with gastroenteropancreatic NETs and sufficient somatostatin receptor uptake. We aim to analyze the safety and efficacy of LU in NETs in a real-world setting.
Methods
Retrospective and multicentric study in pts with NETs treated with LU between 2016 and 2024. Pts’ clinical characteristics, oncological outcomes (objective response rate [ORR], progression-free survival [PFS] and overall survival [OS]) and toxicity profile by CTCAE v.4.0 were analyzed.
Results
We identified 44pts. Age (median): 57 [35-75]. 54.5% were male. We included gastrointestinal (n=16), pancreatic (n=15), pulmonary (n=7) and unknown origin (n=6) NETs. Tumor grade (G): G1 (29.5%), G2 (63.6%) and G3 (4.5%). We described 59.1% of functioning tumors and 35pts (79.5%) debuted in advanced stage. Surgical resection of primary tumor and/or metastases was performed in 50% of cases. 56.8% received ≥ 2 lines of treatment prior to PRRT; which included somatostatin analogs (95.5%), everolimus (36.4%), sunitinib (22.7%) and chemotherapy (34.1%). In the overall population, the median PFS and OS were 25m (95%CI, 18.7-31.3) and 39.1m (95%CI, 32.3-46.0), respectively. We observed poorer PFS in higher tumor G (23.6m vs 36.5m, p=0.26) and in pulmonary NETs 16.3m (95%CI, 9.1-23.5) vs intestinal 23.6m (95%CI, 0.0-48.6) or pancreatic NETs 27.7m (95%CI, 10.5-4.9); p=0.32. Also, we reported worse outcomes in pts with ≥2 metastatic sites (23.6m vs 36.5m, p=0.58). 9.1% developed severe toxicity (G 3-4) and we mostly observed early onset adverse events in 50% of cases. Other treatment-related data are shown in the table. Table: 219P
| Total n (%) | |
| Objective response rate | 15 (38.5) |
| CR | 1 (2.6) |
| PR | 14 (35.9) |
| SD | 18 (46.2) |
| PD | 6 (15.4) |
| Improvement in quality of life | 30 (68.2) |
| PRRT treatment completed | 26 (59.1) |
| Toxicity profile | 23 (52.3) |
| Haematological | 19 (43.2) |
| Anaemia | 8 (18.2) |
| Thrombopenia | 16 (36.4) |
| Myelodysplastic syndrome | 3 (6.8) |
| Hepatic | 1 (2.3) |
| Renal | 3 (6.8) |
| Gastrointestinal | 2 (4.5) |
| Asthenia | 3 (6.8) |
Conclusions
Our results support LU as a feasible, effective and safe treatment in pts with NETs and positive somatostatin receptors. A higher tumor grade and tumor burden may correlate with a worse prognosis.
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
R. Vidal Tocino: Financial Interests, Personal, Invited Speaker: Amgen, Merck, Servier, Bristol-MS, Bayer, MSD; Financial Interests, Personal, Advisory Board: Servier, GSK; Non-Financial Interests, Member: ACLO - Asociación Castellano-leonesa de Oncología, SEOM- Sociedad Española de Oncología Médica; Other, Travel and accommodation: Servier, Roche, MSD. All other authors have declared no conflicts of interest.