Protocol for a systematic review and meta-analysis of CT-guided iodine-125 seed implantation plus chemotherapy versus chemotherapy alone in unresectable pancreatic cancer

Pancreatic cancer is the sixth leading cause of cancer mortality worldwide, with a 5-year survival rate below 15%. Standard first-line chemotherapy yields a median overall survival of only 8–11 months in patients with metastatic disease. Computed tomography (CT)-guided iodine-125 (I-125) radioactive seed implantation, a form of permanent interstitial brachytherapy, has been widely evaluated as an adjunct to systemic chemotherapy; however, the magnitude of its survival benefit remains uncertain. Individual published randomised controlled trials (RCTs) have yielded inconsistent results, and no comprehensive meta-analysis strictly restricted to RCT-level evidence currently exists. This protocol describes a systematic review and meta-analysis designed to quantify the efficacy and safety of CT-guided I-125 seed implantation combined with chemotherapy versus chemotherapy alone in patients with pancreatic cancer.