Systematic Review and Meta-Analysis of Particle Beam Therapy versus Photon Radiotherapy for Skull Base Chordoma: TRP-Chordoma 2024.

Simple Summary: Chordoma is a rare cancer that often occurs at the base of the skull. Treating skull base chordoma is challenging because the tumor is difficult to completely remove with surgery and has low radiosensitivity. This study compared two types of radiation modality: particle beam therapy (PT) and photon radiotherapy (RT). We found that PT provides better progression-free survival compared to photon RT. However, PT also has a higher risk of causing brain necrosis. Our findings suggest that PT is more effective for controlling skull base chordoma, but careful planning is needed to minimize side effects. [Objective] The aim of this study was to compare the efficacy of particle beam therapy (PT) with photon radiotherapy (RT) for treatment of skull base chordoma. [Methods] A systematic review was conducted for skull base chordoma treated with PT or photon RT reported from 1990 to 2022. Data were extracted for overall survival (OS) and progression-free survival (PFS), late adverse events, age, gender, gross total resection (GTR) rates, tumor volume, total irradiation dose, and treatment modality. Random-effects meta-regression analysis with the treatment modality as an explanatory variable was performed for each outcome to compare the modalities. [Results] A meta-analysis of 30 selected articles found 3- and 5-year OS rates for PT vs. photon RT or combined photon RT/proton beam therapy (PBT) of 90.8% (95% CI: 87.4–93.3%) vs. 89.5% (95% CI: 83.0–93.6%), p = 0.6543; 80.0% (95% CI: 75.7–83.6%) vs. 89.5% (95% CI: 83.0–93.6%), p = 0.6787. The 5-year PFS rates for PT vs. photon RT or photon RT/PBT were 67.8% (95% CI: 56.5–76.7%) vs. 40.2% (95% CI: 31.6–48.7%), p = 0.0004. A random-effects model revealed that the treatment modality (PT vs. photon RT or photon RT/PBT) was not a significant factor for 3-year OS (p = 0.42) and 5-year OS (p = 0.11), but was a significant factor for 5-year PFS (p < 0.0001). The rates of brain necrosis were 8–50% after PT and 0–4% after photon RT or photon RT/PBT. [Conclusion] This study shows that PT results in higher PFS compared to photon RT for skull base chordoma, but that there is a tendency for a higher incidence of brain necrosis with PT. Publication and analysis of further studies is needed to validate these findings. [ABSTRACT FROM AUTHOR]