PAROXYSMAL ATRIAL FIBRILLATION IN ELDERLY: LINAC-BASED SBRT ARRHYTHMIA RADIOABLATION PHASE 2 TRIAL
PO-1611
Abstract
PAROXYSMAL ATRIAL FIBRILLATION IN ELDERLY: LINAC-BASED SBRT ARRHYTHMIA RADIOABLATION PHASE 2 TRIAL
Authors: Fabiana Gregucci1, Antonio Di Monaco2, Ilaria Bonaparte1, Alessia Surgo1, Roberta Carbonara1, Maria Paola Ciliberti1, Fiorella Di Guglielmo1, Morena Caliandro1, Eleonora Paulicelli1, Elena Ludovico3, Imma Romanazzi2, Massimo Grimaldi2, Alba Fiorentino1
1Miulli General Regional Hospital, Radiation Oncology, Acquaviva delle Fonti, Italy; 2Miulli General Regional Hospital, Cardiology, Acquaviva delle Fonti, Italy; 3Miulli General Regional Hospital, Radiology, Acquaviva delle Fonti, Italy
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Purpose or Objective
In elderly, paroxysmal atrial fibrillation (AF) is difficult to treat with drugs and catheter ablation due to the higher complication rate. Thus, non-invasive approaches should be favorite. STereotactic Arrhythmia Radioablation (STAR) was used for ventricular tachycardia, but no data are available for LINear ACcelerator (LINAC)-based STAR in AF patients. Based on this background, the primary and secondary endpoints of present prospective phase II trial are to evaluate, respectively, safety and efficacy of LINAC-based STAR for AF elderly patients. Here, clinical, dosimetric and planning data were reported.
Material and Methods
The study was designed as a prospective phase-II trial started in May 2021, conducted in a single, referral center (ClinicalTrials.gov: NCT04575662). The inclusion criteria were: patients aged over 70 years, with symptomatic paroxysmal AF; intolerance or non-response to anti-arrhythmic (ATT) drugs. The primary study endpoint was the 1-month post-STAR safety, as complete STAR delivery and no acute treatment-related adverse events more than G3, assessed according to the Common Terminology Criteria for Adverse Events (version 5.0). Secondary endpoints were: reductions in AF episodes and in AAT, overall survival. The sample planning is 20 cases based on 95% success for the primary endpoint, with a significant level of 5% and a power of 90%. The date of the last follow-up was September 2022.
The STAR treatment was performed in free breathing with a PTV prescription total dose of 25Gy in 1 fraction.
Results
Patient enrollment was closed in July 2022 with an accrual of 20/20 (100%), of these 18 patients were treated, 1 withdrew consent for treatment and 1 was excluded due to unfavorable anatomy. All patients completed STAR. No acute treatment-related adverse events (≥G2) at 1-month from procedure were registered. At a median follow up time of 7 months (range 12-2), 4 patients (25%) developed acute G1 esophagitis, resolved with local lenitive oral treatment and 2 patients (12%) reported a mild asymptomatic pericarditis to the 6-months control chest CT. In 1 patient, cardiac arrest occurred 15 minutes after the procedure, requiring cardiopulmonary resuscitation, without subsequent sequelae. No late side effects were reported. Eight patients, at 6-months from treatment, developed a relapse of AF, in the other 10 no AF episodes and no AAT use were reported.
Mean CTVs, ITVs and PTVs were 23.6 cc, 44.32 cc, 62.9 cc respectively; while the mean prescription isodose level and D2% were 76.5% and 31.2 Gy, respectively. Regarding organ at risk, average heart and left anterior descending artery (LAD) Dmean were 3.9 and 6.3 Gy, respectively; while mean Dmax for LAD, spinal cord, left and right bronchus and esophagus were 11.2, 7.5, 14.3, 12.4 and 13.6 Gy respectively. The Overall Treatment Time (OTT) was 3minutes.
Conclusion
Clinical data suggest that LINAC-based STAR for AF could represent a valid non-invasive alternative therapy for elderly who were excluded from catheter ablation.