1163P - Prognostic value of systemic inflammatory index (SII) in neuroendocrine tumors (NETs) treated with peptide receptor radionuclide therapy (PRRT)

Background

PRRT with ¹⁷⁷Lu-Dotatate (Lutathera®) (LU) offers an effective approach in gastroenteropancreatic NETs. We know that systemic inflammatory (SI) parameters could show poorer results, however, it remains unknown in patients (p) treated with PRRT. We aim to analyze the prognostic value of SI biomarkers in NETs undergoing LU.

Methods

Retrospective and multicentric study of NETs receiving LU between 2016 and 2024. Clinical features and blood test [at baseline (BL) and after two cycles of PRRT] data were collected to determine SI markers and calculate the following ratios: neutrophil to lymphocyte (NLR), monocyte to lymphocyte (MLR), platelet to lymphocyte (PLR) and albumin to lymphocyte (ALR). The cut-off values were determined as the median of each variable, correlating them with progression-free (PFS) and overall survival (OS).

Results

44 patients (p) with NETs were included with a median age of 57 years and 54.5% males. NETs were of gastrointestinal (n=16), pancreatic (n=15), pulmonary (n=7) and unknown (n=6) origin. Tumor grade (G) was G1 (29.5%) and G2/3 (70.5%). 25p (56.8%) received ≥2 lines of treatment prior to PRRT. We observed significant poorer PFS in p with pulmonary vs pancreatic NETs (16.3m vs 27.7m; p=0.02), and a trend inhigher tumor G (23.6m vs 36.5m; p=0.26) and with ≥2 metastatic sites (23.6m vs 36.5m; p=0.58). We identified as BL values of good prognosis lower ratios of NLR, MLR, PLR and ALR. Also, BL SII (as a set of the parameters analyzed) showed a favorable trend with a score ≤2 in PFS (34.7m vs 12.8m, p=0.07) and in OS (NR vs 29.6m; p=0.09). After2 cycles of LU, SII score ≤2 significantly predicted better OS (NR vs 12.6m; p=0.02).

Table: 1163P

Prognostic value of inflammatory biomarkers in patients with neuroendocrine tumors treated with PRRT