Carbon Ion Radiotherapy for Locally Advanced Pancreatic Cancer: A Systematic Review and Pooled Analysis of Single-arm Studies.

Abstract

The role of carbon ion radiation therapy (CIRT) in treating locally advanced pancreatic cancer (LAPC) lacks high-level medical evidence. This study aimed to assess the efficacy and safety of CIRT for LAPC through a pooled analysis of single-arm studies. Prospective or retrospective clinical studies of CIRT for LAPC with or without chemotherapy before, concurrent, and/or after CIRT were included in the analysis. A systematic search of the Embase, PubMed, and Cochrane Library databases was conducted for studies until September, 2025. These articles were independently screened, and data were extracted by 2 researchers. Statistical analysis of outcomes was performed using STATA 15.1. A total of 522 related articles were retrieved, and 9 single-arm studies with a total of 406 patients with LAPC were included. The pooled local control (LC) rates at 1 and 2 years were 84% and 64%, respectively, with higher prescribed doses showing improved LC compared with lower doses (89% vs 69% at 1 year; 72% vs 30% at 2 years). The overall survival rates at 1 and 2 years were 65% and 38%, respectively. A clear survival benefit of CIRT was observed in studies with concurrent chemotherapy than without (73% vs 53% at 1 year; 44% vs 22% at 2 years). Prior chemotherapy administration reduced the incidence of distant metastases (69% vs 85%). Regarding toxicities above G3, the pooled incidences of nonhematological toxicity and hematological toxicity were 8% and 24%, respectively. Encouraging LC and overall survival outcomes were observed in this pooled analysis of CIRT as a plausible treatment strategy for LAPC. Subgroup analyses suggested that higher doses, concurrent chemotherapy, and prior chemotherapy may further enhance the efficacy. Meanwhile, CIRT has acceptable toxicities even when it is administered concurrently with chemotherapy.