Chidamide Plus Etoposide and Cisplatin/Carboplatin as First-line Treatment for Extrapulmonary Neuroendocrine Carcinoma

Inclusion Criteria: 1. Age ≥ 18 years; 2. Histologically confirmed locally advanced and metastatic extrapulmonary neuroendocrine carcinoma; 3. No systematic treatments for neuroendocrine carcinoma are received before enrollment; 4. ECOG ≤ 2; 5. Have at least one measurable lesion according to RECIST version 1.1, and the lesion has not received any local treatments; 6. Absolute neutrophil count ≥ 1.5×109 / L, platelet count ≥ 100×109 / L, hemoglobin ≥ 90 g/L; 7. Have ability to sign a written informed consent. Exclusion Criteria: 1. Have surgery or trauma within 4 weeks before enrollment, or are expected to receive surgical treatment; 2. Previous use of HDAC inhibitors; 3. Allergy to related drug components; 4. Have a medical history of immune deficiency diseases, or organ transplantation; 5. Have uncontrolled or significant cardiovascular disease; 6. Abnormal liver function (total bilirubin \> 1.5×upper limit of normal); Transaminases (ALT/AST) \>2.5×upper limit of normal (\>5x upper limit of normal for patients with liver metastases), abnormal renal function (serum creatinine \> 1.5×upper limit of normal); 7. Pregnancy ; 8. Have serious diseases that may endanger the safety of patients, or affect patients to complete the research; 9. Any serious mental or cognitive disorder; 10. Patients are currently enrolled in another drug clinical trial within 4 weeks prior to enrollment; 11. Any other condition which is inappropriate for the study in the opinion of the investigators.