Abstract 217P
Background
177-LuDOTATE is an effective but expensive treatment for patients (pts) with advanced neuroendocrine tumors (NETs). Reducing treatment-related costs, such as the number of images (CT scans), could improve access of 177-LuDOTATE to pts. We evaluated the rate of early tumor progression (within 8-10 weeks) and associated prognostic factors in pts with NETs treated with 177-LuDOTATE. Our objective was to identify which pts could be spared of frequent radiological images.
Methods
We retrospectively included all pts diagnosed with NETs between 2006 and 2023 who received at least one cycle of 177-LuDOTATE. The primary objective was to evaluate the rate of early radiological disease progression right after two cycles of 177-LuDOTATE. Secondary objectives were to evaluate prognostic factors (grade, tumor location, hormone secretion, 177-LuDOTATE treatment line) associated with progression-free survival (PFS) and overall survival (OS) in Cox proportional hazards models.
Results
Fifty-nine patients were included: the most common tumor locations were small bowel (46%) and pancreas (34%). The median number of cycles was 3 (range 1-6). Overall, early progression was found in 10 (17%) cases. Among 14 patients who received two cycles or less of 177-LuDOTATE, 10 (72%) stopped treatment due to disease progression, with 5 pts having a G2 (ki67: 5-25%) and 4, a G3 (ki67: 25-90%) NET. The median overall survival (OS) was 43.7 months, while the median progression-free survival (PFS) was 16.1 months. In the Cox multivariable analysis, higher grade (G2 or G3 vs G1) were significantly associated with inferior PFS and OS. The median PFS of G1, G2 and G3 NET pts were: 34.1, 11.7 and 6.1 months (p = 0.01), respectively.
Conclusions
We consider it is safe to omit CT scans right after cycle 2 of 177-LuDOTATE in pts with G1 and indolent NETs, reserving images for after treatment completion, with the intent to reduce costs. For patients with more aggressive disease, such as those with G2 and G3 NETs, it is advisable to perform images after each 177-LuDOTATE cycle.
Legal entity responsible for the study
Centro Internacional de Pesquisa (CIPE) do A.C. Camargo Câncer Center.
Funding
Has not received any funding.
Disclosure
R.S.P. Riechelmann: Financial Interests, Personal, Invited Speaker: Ipsen; Non-Financial Interests, Personal, Advisory Board: Ipsen. All other authors have declared no conflicts of interest.