Detailed evaluation of the long-term outcomes of repeat stereotactic radiosurgery for brain arteriovenous malformations: A single-center retrospective study.
Repeat stereotactic radiosurgery (SRS) is a treatment option for residual brain arteriovenous malformations (AVMs) following incomplete response to an initial SRS, and this study aimed to clarify the long-term outcomes. Patients who underwent repeat SRS between 1990 and 2022 were retrospectively analyzed. Primary outcome was a favorable patient outcome, defined as AVM obliteration without post-SRS hemorrhage or symptomatic T2 signal change/late radiation-induced complications (LRICs). Fifty-eight patients with a median follow-up of 97 months were analyzed. Six patients (10.3%) experienced recurrent hemorrhage between the initial and repeat SRS, indicating high risk of hemorrhage in this cohort. Favorable patient outcome was achieved in 41 patients (70.7%), with 3- and 5-year cumulative rates of 68.1% and 79.2%. Maximum dose was associated with a favorable patient outcome (hazard ratio [HR] 1.07, 95% confidence interval [CI] 1.01-1.14; p = 0.016). AVM obliteration was achieved in 47 patients (81.0%), with 3- and 5-year rates of 69.2% and 85.0%. Three patients (5.2%) experienced post-repeat SRS hemorrhage, with an annual hemorrhage rate of 1.66%/person-year. Five patients (8.6%) experienced LRICs requiring resection with 5- and 10-year rates of 4.0% and 6.9%. T2 signal change after initial SRS (HR 17.11, 95% CI 1.06-276.55; p = 0.046) and initial maximum diameter > 25 mm (HR 21.12, 95% CI 1.01-442.76; p = 0.049) were associated with LRICs. Repeat SRS demonstrated long-term favorable outcomes in patients at a high risk of hemorrhage. A longer follow-up duration is important, as in the case of LRICs, which could be predicted by T2 signal change and nidus size before repeat SRS.
Authors
Hirata Hirata, Umekawa Umekawa, Hasegawa Hasegawa, Shinya Shinya, Katano Katano, Koizumi Koizumi, Saito Saito
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