4175 - Extra-pulmonary (EP) high grade (HG) neuroendocrine carcinoma (NEC): real-life outcomes of fifty-eight patients from a Portuguese cancer center.

Background

EP-HG-NEC are rare malignancies with poor prognosis, mainly from the gastrointestinal (GI) tract, although they may originate anywhere in the body due to the wide distribution of the neuroendocrine system. Platinum plus etoposide regimen (PE) is standard of care. Our goal was to characterise EP-HG-NEC at our institute, evaluate primary tumor location as prognostic factor and the effectiveness of PE as first-line (1L) therapy.

Methods

Records of patients (pts) diagnosed with EP-HG-NEC at a Portuguese terciary cancer center were reviewed retrospectively (January 2000-March 2019).

Results

Fifty-eight pts (52% males) identified: median (m) follow-up was 21 months (M) (range: 4-43); at diagnosis, m age was 61 years (range 30-85), 81% had ECOG performance status of 0-1, 83% were symptomatic, 64% had metastatic disease (70% with liver metastasis), 48% had Ki67 above 55%. Primary tumor location was GI in 27 pts (33% Esophagus, 19% colorectal, 15% pancreas), unknown (CUP) in 24 pts and genitourinary (GU) in 7 pts. For all EP-HG-NEC, m overall survival (OS) was 15,7M. Pts with CUP seemed to have a worse prognosis (mOS=8,5M), whereas GU and GI had a similar prognosis (mOS=19,2 and 18,7M, respectively) (p = 0.357).Thirty-nine pts (67%) got PE, 7 pts received a different chemotherapy (ChT) regimen and 9 pts got best supportive care (BSC) only. mPFS was 4,6M for PE group and 7,3M for other ChT regimen group (platinum alone, CAPTEM, 5FU-STZ) with no statistical significance (p = 0.547). mOS was 15,7M for PE group and 6,9M for BSC group (p = 0.54). With PE, 41% had grade 3 adverse events and no toxic deaths were reported. After 1L PE, 24 pts received a second L ChT, 50% with CAPTEM.

Conclusions

Considering the limited data available, this retrospective case series contributes to a better understanding of this entity. Primary tumor location tends to predict outcome. We hypothesised that delaying treatment initiation for CUP while searching for primary tumor might be related to worse outcomes. The outcomes of 1L PE suggest that other options might be needed as standard of care. EP-HG-NEC has prognostic heterogeneity, multi-center studies are needed.

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.