Dose response and architecture in volume staged radiosurgery for large arteriovenous malformations: A multi-institutional study.
Radiotherapy and Oncology : Journal of the European Society for Therapeutic Radiology and Oncology
BACKGROUND: Optimal treatment paradigm for large arteriovenous malformations (AVMs) is controversial. Volume-staged stereotactic radiosurgery (VS-SRS) provides an effective option for these high-risk lesions, but optimizing treatment for these recalcitrant and rare lesions has proven difficult.
METHODS: This is a multi-centered retrospective review of patients treated with a planned prospective volume staging approach to stereotactically treat the entire nidus of an AVM with volume stages separated by intervals of 3-6 months. A total of 9 radiosurgical centers treated 257 patients with VS-SRS between 1991 and 2016. We evaluated near complete response (nCR), obliteration, cure, and overall survival.
RESULTS: With a median age of 33 years old at the time of first SRS volume stage, patients received 2-4 total volume stages and a median follow up of 5.7 years after VS-SRS. The median total AVM nidus volume was 23.25 cc (range: 7.7-94.4 cc) with a median margin dose per stage of 17 Gy (range: 12-20 Gy). Total AVM volume, margin dose per stage, compact nidus, lack of prior embolization, and lack of thalamic location involvement were all associated with improved outcomes. Dose >/= 17.5 Gy was strongly associated with improved rates of nCR, obliteration, and cure. With dose >/= 17.5 Gy, 5- and 10-year cure rates were 33.7% and 76.8% in evaluable patients compared to 23.7% and 34.7% of patients with 17 Gy and 6.4% and 20.6% with(p = 0.004). Obliteration rates in diffuse nidus architecture with32.3% with doses >/= 17 Gy at 5 years (p = 0.007). Comparatively, lesions with a compact nidus architecture exhibited obliteration rates at 5 years were 10.7% vs 9.3% vs 26.6% for dose >17 Gy vs 17 Gy vs >/=17.5 Gy.
CONCLUSION: VS-SRS is an option for upfront treatment of large AVMs. Higher dose was associated with improved rates of nCR, obliteration, and cure suggesting that larger volumetric responses may facilitate salvage therapy and optimize the chance for cure.
Seymour ZA, Chan JW, Sneed PK, Kano H, Lehocky CA, Jacobs RC, Ye H, Chytka T, Liscak R, Lee CC, Yang HC, Ding D, Sheehan J, Feliciano CE, Rodriguez-Mercado R, Chiang VL, Hess JA, Sommaruga S, McShane B, Lee J, Vasas LT, Kaufmann AM, Grills I, McDermott MW. Dose response and architecture in volume staged radiosurgery for large arteriovenous malformations: A multi-institutional study. Radiother Oncol. 2020 Mar;144:180-188. doi: 10.1016/j.radonc.2019.09.019. Epub 2019 Dec 10. PMID: 31835173.