Lenvatinib Plus Chemotherapy for pNET Liver Metastases

Inclusion Criteria: * Inclusion Criteria: * Age 18 to 75 years. * Histologically or cytologically confirmed pancreatic neuroendocrine tumor. * Radiologically confirmed liver metastases. * Disease progression or treatment failure after first-line systemic therapy, with eligibility for second-line treatment. * At least one measurable lesion according to Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1. * Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1. * Adequate hematologic, hepatic, and renal function as assessed by the investigator. * Life expectancy of at least 12 weeks. * Ability to understand and willingness to sign a written informed consent form. Exclusion Criteria: * Poorly differentiated neuroendocrine carcinoma or neuroendocrine tumor originating from a site other than the pancreas. * Previous treatment with lenvatinib. * Uncontrolled or clinically significant cardiovascular disease, including uncontrolled hypertension. * Active severe infection or other uncontrolled serious systemic disease. * Known central nervous system metastases that are symptomatic or uncontrolled. * Pregnancy or breastfeeding. * Participation in another interventional clinical study that may interfere with the outcomes of this study. * Any other condition that, in the opinion of the investigator, may make the participant unsuitable for participation in this study.