Alberto Bongiovanni,1 Nada Riva,1 Marianna Ricci,1 Chiara Liverani,1 Federico La Manna,1 Alessandro De Vita,1 Flavia Foca,2 Laura Mercatali,1 Stefano Severi,3 Dino Amadori,4 Toni Ibrahim1 1Osteoncology and Rare Tumors Center, 2Unit of Biostatistics and Clinical Trials, 3Nuclear Medicine Unit, 4Department of Medical Oncology, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Meldola, FC, Italy 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/m2 was administered on days 1–3 followed by etoposide 100 mg/m2 on days 1–3 every 21 days. Carboplatin 300 mg/m2 was administered on day 1 followed by etoposide 100 mg/m2 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 (P55%, 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