Abstract 33P
Background
According to the latest WHO classification, within high-grade NEN, the distinction between neuroendocrine tumor (NET) G3 and carcinoma (NEC) G3 is clinically and prognostically meaningful. Platinum-based chemotherapy remains the recommended first-line treatment in metastasized NEC patients, but there is no established standard for NET G3.
Methods
Retrospective analysis of high-grade NEN treated in our hospital with platinum since August 2014, after pathology review and re-classification in NET G3 or NEC G3. We analyzed demographic features, platinum response and survival. We used IBM SPSS Statistics v.25.
Results
A total of 26 patients (69.2% male, 30.8% female) were included. About primary location of the tumour, 38.5% were pancreatic, 19.2% gastrointestinal, 3.2% bronchial, 11.5% other locations and 26.9% unknown. After pathology review, 23.1% were NET G3 and 76.9% NEC G3. Furthermore, 61.5% had Ki67 > 50%, and 65.4% > 20 mitosis/10HPF. 92.3% received platinum as first line of treatment (53.8% with carboplatin and 46.2% with cisplatin). In whole group, we observed a median progression-free survival (PFS) of 5.8 months, median overall survival (OS) of 10.7 months, a response rate (RR) of 50%, and disease control rate (DCR) of 65.4%. When we analyzed by pathological subtypes, in NET G3 we got 4.6 months of PFS, 26.8 months of OS, 16.7% of RR and 50% of DCR. On the other hand, in NEC G3 we found 5.9 months of PFS, 9.8 months of OS, 65% of RR and 75% of DCR. However, the differences in PFS and OS were not statistically significant (p value 0.527 and 0.198 respectively). 50% patients received a second line of treatment, in most cases irinotecan-based chemotherapy or re-challenge with platinum, with a median PFS of 4.1 months, RR of 15.4% (all with platinum re-challenge) and DCR of 38.5%. At the moment of the analysis, 80.8% of patients were passed away.
Conclusions
Although platinum-based chemotherapy is a good option for first line in all NEN G3, it seems to be more effective in NEC than in NET G3, with more RR and DCR (even though the differences in survival are not statistically significant). Although the benefit of the second lines is very debatable, if considered we should prioritize the rechallenge if possible.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
P. Santos Fernandez.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.