Abstract 1169P
Background
The 2019 World Health Organization (WHO) classification of neuroendocrine neoplasia (NEN) introduced the new category of well-differentiated NEN with Ki67 proliferation index ≥20% (NET G3). Fluoropyrimidine-based regimens with oxaliplatin (FOLFOX/XELOX) were a treatment option in neuroendocrine carcinomas with low Ki67, but their efficacy in the newly defined NET G3 category is unknown. Objective of this study was to describe FOLFOX/XELOX efficacy in NET G3 and identify factors associated with outcome.
Methods
We retrospectively collected consecutive gastro-entero-pancreatic NET G3 patients who received a FOLFOX/XELOX as first-line treatment at 4 NEN-dedicated Italian Centers. Concomitant somatostatin analog (SSA) treatment was allowed. Factors associated with response by RECIST, progression-free survival (PFS), and overall survival (OS) were analyzed.
Results
Thirty-four NET G3 patients (median age 55 years) were identified. Twenty-two patients (65%) had a pancreatic NET, while 12 (35%) had a gastrointestinal primary. Median Ki67 was 30% (range 20-50). Treatment was FOLFOX in 17 (50%) and XELOX in 17 patients (50%), while 16 (47%) received also concomitant SSA. After a median follow-up of 21.9 months, median PFS was 7.9 months (95%CI: 6.8-11.4) and median OS was 30.0 months (95%CI: 13.8-NA). The 13 patients whose tumor responded to FOLFOX/XELOX (38% [95%CI 22-56]) had longer PFS (21.9 vs 7.3 months; p<0.001) and OS (78.9 vs 10.0 months; p=0.01) compared with those who did not respond. After correcting for potential confounding factors with multivariate analysis, objective disease response to FOLFOX/XELOX was associated with a reduced risk for progression (HR: 0.20 [95%CI: 0.07-0.58]; p=0.003) and death (HR: 0.26 [95%CI: 0.07-0.98]; p=0.046) while higher Ki67 was associated with an increased risk for progression (HR: 1.09 [95%CI: 1.02-1.14]; p=0.013) and for death (HR: 1.09 [95%CI: 1.01-1.17]; p=0.023).
Conclusions
Fluoropyrimidine-based regimens with oxaliplatin (FOLFOX/XELOX) may be active and effective in NET G3 of gastro-entero-pancreatic origin.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.