Efficacy of Stereotactic Body Radiotherapy (SBRT) Combined With Maintenance Therapy Compared to Maintenance Therapy Alone in Advanced Pancreatic Cancer

Pancreatic cancer is one of the most aggressive malignancies, and most patients are diagnosed at an advanced stage, making them ineligible for surgery. Despite systemic chemotherapy being the standard treatment for advanced pancreatic cancer, the prognosis remains poor, with median survival often less than one year. The addition of radiotherapy has shown some promise in improving outcomes, particularly in the setting of local control. This Phase II, multicenter, randomized controlled trial evaluates the combination of Stereotactic Body Radiotherapy (SBRT) with maintenance therapy versus maintenance therapy alone in patients with advanced pancreatic cancer. SBRT offers a high dose of radiation with minimal damage to surrounding healthy tissues, potentially enhancing tumor control while preserving immune function, a key challenge in pancreatic cancer treatment. Moreover, SBRT has shown potential in stimulating anti-tumor immune responses, thus converting "cold" tumors into "hot" tumors that may respond better to subsequent therapies. Patients eligible for this trial will have completed at least four months of first-line chemotherapy, achieving stable disease (SD) or partial response (PR) according to RECIST 1.1 criteria. After completion of the chemotherapy, they will be randomized into two groups: the experimental group will receive SBRT in addition to maintenance chemotherapy, while the control group will receive maintenance chemotherapy alone. The chemotherapy regimen will be based on the patient's first-line treatment. The study will evaluate the primary endpoint of one-year overall survival (OS) rate, alongside secondary endpoints including overall survival, progression-free survival (PFS), local control rate (LCR), and adverse event (AE) rates. In addition, exploratory endpoints include identifying potential biomarkers associated with the anti-tumor efficacy of SBRT and maintenance therapy. These biomarkers include PD-L1 expression, tumor mutational burden (TMB), and changes in immune cell subsets in blood and tumor tissue. The results of this study will provide valuable insights into the combination of SBRT and maintenance chemotherapy as a potential treatment option for advanced pancreatic cancer, which may lead to improved survival outcomes and a better understanding of the biological mechanisms that drive treatment response.