CtDNA-guided Maintenance Therapy in Pancreatic Cancer

Inclusion Criteria: * Age ≥18 years, male or female * Histologically or cytologically confirmed primary diagnosis of pancreatic ductal adenocarcinoma (PDAC) * No evidence of distant metastasis (M0) * Underwent R0 radical resection within 3 months prior to enrollment * ECOG performance status of 0-1 * Life expectancy ≥3 months * Patient or legal guardian is able to understand the study requirements and willing to provide written informed consent Exclusion Criteria: * Prior history of radiotherapy, chemotherapy or surgical treatment for pancreatic cancer * Concurrent severe organ dysfunction or hematologic disorders * Tumor involvement of celiac axis or superior mesenteric artery, locally advanced disease, or presence of distant metastases * Poor general condition deemed unable to tolerate chemotherapy * History of other malignancies within past 5 years (except adequately treated carcinoma in situ of cervix or basal cell carcinoma of skin) * Any severe or uncontrolled systemic disease that may affect risk/benefit assessment, including but not limited to: uncontrolled hypertension, active hepatitis B or C infection, HIV infection * Patient or guardian unable to comprehend study objectives and requirements * Any other condition that in the investigator's judgment would make the patient unsuitable for study participation