Efficacy of first-line chemotherapy based on primary site of tumor versus etoposide-platinum in advanced gastroenteropancreatic neuroendocrine carcinoma.

Background: Gastroenteropancreatic neuroendocrine carcinomas (GEP-NECs) constitute a rare and aggressive group of malignancies usually with widespread disease. There are limited studies on GEP-NECs, and therefore, we aim to acquire more information on the clinical features, treatment regimens, and prognosis.

Methods: Data from advanced GEP-NECs patients who had not previously received systemic treatment for advanced disease at The First Affiliated Hospital of Nanjing Medical University from 2010 to 2022 were retrospectively collected. Relationships between clinical-pathological features, treatment regimens, and prognosis were investigated using Kaplan-Meier curves and cox regression models.

Results: A total of fifty-four patients were enrolled in the study. The median age was 65.5 years and 79.6% were male. At diagnosis, 51.9% and 3.7% of patients developed liver and brain metastasis respectively. Sixteen (29.6%) patients received chemotherapy according to primary site of tumor (PST), while thirty-eight (70.4%) were treated with etoposide-platinum (EP) regimen, which based on the first-line treatment of advanced small cell lung cancer (SCLC). No significant differences on progression-free survival (PFS) and response rate were observed between these two groups. Univariate survival analysis showed that liver metastasis, elevated baseline serum carcinoembryonic antigen, elevated baseline serum neuron-specific enolase, elevated baseline serum lactate dehydrogenase, and elevated baseline serum neutrophil-to-lymphocyte ratio (NLR) were associated with shorter PFS. After multivariate analysis, elevated NLR was the only factor that remained significantly associated with shorter PFS (P=0.01).

Conclusions: GEP-NECs are aggressive neoplasms, of which elevated NLR is proven to be an independent negative predictor. Treatment regimens based on PST are not inferior to regiments based on SCLC (EP) for GEP-NECs patients. Large-scale, prospective randomized controlled trials are required to establish the standard of care.