THU511 Somatostatin Analogs Or Active Surveillance In Sporadic And MEN1 Associated Non-functioning Pancreatic Neuroendocrine Tumors

Abstract Disclosure: S. Raia: None. S. Chiloiro: None. M. Maratta: None. B. Maiorano: None. E. Rossi: None. M. Brizi: None. V. Rufini: None. L. De Marinis: None. G. Rindi: None. G. Schinzari: None. A. Pontecorvi: None. G. Tortora: None. A. Bianchi: None. Introduction: Non-functioning (NF), sporadic and MEN1 associated, G1-G2 pancreatic neuroendocrine tumors (PanNETs) usually display an indolent course. Surgery is the first-choice treatment for localized tumors >2 cm. Unresectable or metastatic PanNETs expressing somatostatin receptors (SSTRs) are treated with somatostatin analogs (SSAs). The standard treatment for patients with PanNETs ≤2cm is active surveillance (AS). Yet no evidence of the value of SSA treatment exist in such patient population. Aim(s): To assess the clinical value of SSAs in patients with PanNETs ≤2cm. Material and methods: Data from patients (pts) NF, G1-G2 PanNETs≤2cm were retrospectively collected. Median progression-free survival (mPFS) and response rate (RR) were analyzed in SSA group and AS group. Results: From June 2007 to June 2022, data from 46 pts were considered: 29 pts, who declined an AS program but had not indication for surgery, entered in the SSA group (21 sporadic and 8 MEN1 associatd PanNET) and 17 in the AS group. At a median follow-up of 64.8 months for sporadic and of 63.9 for MEN1 associated PanNET, no disease progression (PD) was reported in the SSA group, without differences between sporadic and MEN1 associated PanNET. While the PD rate was 23.5 % in the AS group, with a mPFS of 36.2 months. Conclusion: SSAs therapy showed significant antiproliferative activity in patients with both sporadic and MEN1 associated NF, G1-G2 PanNETs ≤2cm. SSAs treatment delay tumor progression and distant spread in small lesions that sometimes may reveal an unpredictable aggressiveness. Presentation: Thursday, June 15, 2023