First-line chemotherapy in patients with metastatic gastroenteropancreatic neuroendocrine carcinoma

Background and aim: To investigate the efficacy of platinum-based chemotherapy in patients with metastatic gastroenteropancreatic neuroendocrine carcinoma (mGEP-NEC) and define predictive and prognostic factors. Methods: Twenty mGEP-NEC patients were treated with cisplatin or carboplatin/etoposide between April 2010 and October 2014. Both large-cell and small-cell histologies were included. Cisplatin 25 mg/m(2) was administered on days 1-3 followed by etoposide 100 mg/m2 on days 1-3 every 21 days. Carboplatin 300 mg/m(2) was administered on day 1 followed by etoposide 100 mg/m(2) on days 1-3. Results: Of the 19 evaluable patients, 13 obtained a partial response, four showed stable disease, and two progressed. Median overall survival (mOS) was 13.5 months and median progression-free survival (mPFS) was 10.9 months. Gallium-68 positron emission tomography/computerizsed tomography-positive patients had a higher, albeit not significantly, OS than those with negative results (75% vs 34.3% at 18 months; P=0.06). mPFS was 19.3 and 6.3 months (P<0.01) in mGEP-NEC patients with Ki67 <= 55% or >55%, respectively. mOS was 8.1 months in the latter group but was not reached in the Ki67 <= 55% group (P-value=0.039). Patients with a lower body mass index (BMI) had a better prognosis in terms of both OS and PFS. Patients with BMI >= 25 had a mOS of 11.7 months (P=0.0293) and a mPFS of 6.2 months (P=0.0057). Conclusion: Platinum-based chemotherapy showed good efficacy in mGEP-NEC patients. Those with Ki67 <55%, positive Gallium-68 positron emission tomography/computerized tomography and BMI <25 had a better prognosis.