1197P - Somatostatin analogs or active surveillance in sporadic non-functioning pancreatic neuroendocrine tumors

Background

Non-functioning, sporadic, G1-G2 pancreatic neuroendocrine tumors usually display an indolent course. Surgery is the first-choice treatment for localized tumors >2 cm. Unresectable or metastatic PanNETs expressing somatostatin receptors are treated with somatostatin analogs (SSAs). The PROMID and the CLARINET studies proved the SSA antiproliferative effect in advanced gastro-entero-pancreatic neuroendocrine tumors. The standard treatment for patients with PanNETs ≤2cm is active surveillance. Yet no evidence of the value of SSA treatment exist in such patient population.

Methods

We retrospectively collected data from 72 patients with sporadic non-functioning G1-G2 PanNETs≤2cm, 31 treated with somatostatin analogs and 41 underwent to active surveillance at our Institution. Median progression-free survival (mPFS) and response rate (RR) were analyzed in SSA group and AS group. Survival was described by the Kaplan-Meier method with Mantel-Haenszel log-rank test. Cox-regression analysis was used to assess, both singularly and collectively, the weight of clinically relevant covariates on survival outcomes. Statistical significance was declared at two-sided p<0.05.

Results

At a median follow-up of 53.7 months, the median progression free survival was not reached in the treatment group versus an estimated PFS of 85 months in the control group (HR 0.11, p = 0.01), with a rate of progression or death up to 21.9% in the active surveillance group. Further, in the group of patients treated with somatostatin analogs response rate was 16.1% with one complete response.

Conclusions

Our monocentric experience demonstrated a significant antiproliferative activity of somatostatin analogs in patients with sporadic, non-functionating G1-G2 PanNETs ≤2cm delaying tumor progression and distant spread in small lesions that sometimes may reveal an unpredictable aggressiveness.

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.