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The following is a summary of “Refining Treatment Planning in STereotactic Arrhythmia Radioablation (STAR): Benchmark Results and Consensus Statement from the STOPSTORM.eu Consortium,” published in the August 2024 issue of Oncology by Trojani et al.
STereotactic Arrhythmia Radioablation (STAR) has demonstrated promising potential in treating patients with refractory ventricular tachycardia (VT), yet the clinical data remains limited and varied. To address this, the STOPSTORM.eu consortium was formed to explore and standardize STAR practices across Europe. This benchmark study aimed to evaluate the current treatment planning practices within the STOPSTORM project to establish a baseline for future harmonization.
In this study, planning target volumes (PTVs) overlapping extra-cardiac organs-at-risk and cardiac substructures were delineated for three STAR cases. Participating centers were tasked with developing single-fraction treatment plans with a 25 Gy dose prescription based on their in-house clinical protocols. An expert panel meticulously reviewed all submitted treatment plans, and a quantitative crowd knowledge-based analysis was conducted using independent software to assess parameters relevant to the ICRU report 91 and to generate crowd dose-volume-histograms. Subsequently, treatment planning consensus statements were formulated through a dual-stage voting process.
A total of 20 centers contributed 67 treatment plans for analysis. Most of these (75%) plans utilized Intensity Modulated Arc Therapy (IMAT) with 6 MV flattening-filter-free beams. The dose prescription methods predominantly relied on PTV D95% (49%) or D96-100% (19%). Many centers opted to reduce PTV coverage to mitigate risks to nearby extra-cardiac organs at risk (75%) and cardiac substructures (50%). The PTV D0.035cm³ doses varied widely, ranging from 25.5 Gy to 34.6 Gy, indicating significant dose inhomogeneity. Estimated treatment times, excluding motion compensation and setup, ranged from 2 to 80 minutes. The consensus statements revealed strong agreement on beam technique planning, dose calculation, prescription methods, and balancing target coverage against sparing extra-cardiac critical structures. However, no consensus was reached regarding dose limitations for cardiac substructures and the acceptable level of dose inhomogeneity within the target.
In conclusion, this multi-center benchmark study under the STOPSTORM initiative identified significant agreement on several key aspects of STAR treatment planning yet highlighted areas of disagreement that need further resolution. The established consensus statements provide a foundational guideline to effectively standardize and harmonize STAR practices. Nonetheless, there remains a critical need for robust clinical data to develop actionable and comprehensive treatment planning guidelines.
Source: sciencedirect.com/science/article/abs/pii/S0360301624031717
