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Hypofractionated Stereotactic Radiosurgery for Cerebral AVMs: A Preliminary Report on Bleeding Risk and Obliteration Rate
I. J. Radiation Oncology d Biology d Physics
S638
2892
Volume 81, Number 2, Supplement, 2011
Hypofractionated Stereotactic Radiosurgery for Cerebral AVMs: A Preliminary Report on Bleeding Risk and Obliteration Rate
S. C. Blamek1, D. Larysz2, L. Miszczyk1, A. Rudnik2, A. Idasiak3, K. Ficek1, R. Tarnawski3 1
Department of Radiotherapy, Maria Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, Gliwice Branch, Gliwice, Poland, 2Department of Neurosurgery, Silesian University of Medicine, Katowice, Poland, 3Maria Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, Gliwice Branch, Gliwice, Poland Purpose/Objective(s): Stereotactic radiosurgery is a widely accepted method of treatment for small, surgically inaccessible arteriovenous malformations (AVMs) of the brain. Treatment of large AVMs however is more complicated because of dose-limiting volume of the lesion. Staged-volume or hypofractionated radiosurgery can be the way to deliver a curative dose to an AVM without significantly increased risk of radiation-induced damage. The aim of our study is to assess the safety and efficiency of hypofractionated radiosurgery for large brain AVMs or lesions located in eloquent areas of the brain with special regard to obliteration rates and bleeding risk after the treatment. Materials/Methods: Of 126 patients treated for brain AVMs between 2001 and 2009, forty-nine had hypofractionated stereotactic radiosurgery. There were 25 males and 24 females, mean age was 36 and ranged between 14 and 71 years. Mean and median volume of the lesions were 25.07 and 18.05 ccm, respectively and ranged between 0.36 - 153.98 ccm. Mean dose was 19.9 Gy and ranged between 12 and 28 Gy delivered in 2 - 4 fractions. Mean and median follow-up time was 28.9 and 23.8 months, respectively. Actuarial obliteration rates and annual bleeding hazard were calculated using Kaplan-Meier survival analysis and lifetables. Results: Two patients bled after the treatment, both within 6 months after irradiation. Annual bleeding hazard rates were 4.5%, 1.6% and 2.6% after one, two and 3 years of follow-up, respectively. In one patient significant neurological deterioration (right hemiparesis) was observed after hemorrhage. Actuarial obliteration rates were 7%, 11% and 21% after one, two and three years of follow-up, respectively. Two patients experienced transient neurological deterioration requiring hospitalization, another four had transient neurological symptoms which resolved without treatment. No new permanent neurological deficits that could be attributed to irradiation were observed. Conclusions: Obliteration rates after hypofractionated radiosurgery for brain AVMs are low but reliable estimation requires longer follow-up. Bleeding risk is highest within the first year after the treatment. Hypofractionated radiosurgery is not associated with a significant risk of permanent neurological deficits. Author Disclosure: S.C. Blamek: None. D. Larysz: None. L. Miszczyk: None. A. Rudnik: None. A. Idasiak: None. K. Ficek: None. R. Tarnawski: None.
2893
Two-fraction Proton Beam Stereotactic Radiosurgery For High-Risk Inoperable Cerebral Arteriovenous Malformations (AVMs)
H. A. Shih1, J. A. Hattangadi2, P. H. Chapman1, M. R. Bussiere1, A. Niemierko1, C. S. Ogilvy1, A. Rowell1, J. Daartz1, J. S. Loeffler1 1
Massachusetts General Hospital, Boston, MA, 2Harvard Radiation Oncology Program, Boston, MA
Purpose/Objective(s): To evaluate patients with high-risk cerebral AVMs (eloquent brain location or large size) who underwent two-staged proton stereotactic radiosurgery (PSRS). Materials/Methods: From 1991 - 2009, 59 patients with high-risk cerebral AVMs received two-staged PSRS. Median nidus volume was 23cc (range 1.4 - 58.1 cc), 70% of cases had nidus volume $ 14cc, and 34% were in critical locations (brainstem, basal ganglia). Median modified radiosurgery score, calculated by: (0.1)(nidus volume, cc) + (0.02) (age, years) + (0.5) (location; frontal/temporal/parietal/occipital/ intraventricular/corpus callosum/cerebellar = 0, basal ganglia/thalamus/brainstem = 1) was 3.19 (range 0.9 - 6.9). Many patients had prior surgery or embolization (40%) or prior PSRS (12%). The most common prescription was 16 Gy radiobiologic equivalent (Gy[RBE]) in two fractions, prescribed to the 90% isodose. Results: At a median follow-up of 56.1 months, 9 patients (15%) had complete and 20 (34%) had partial obliteration. Patients with complete obliteration received higher total dose than those with partial or no obliteration (mean dose 17.6 vs. 15.5, p = 0.01). Median time to complete obliteration was 62 months (range 23 - 109) and 5-year actuarial rate of partial or complete obliteration was 33%. Five-year actuarial rate of hemorrhage was 22% (95% CI 12.5 - 36.8%) and 14% (n = 8) suffered fatal hemorrhage. Lesions with higher AVM scores were more likely to hemorrhage (p = 0.024) and less responsive to radiation (p = 0.026). The most common complication was grade I headache acutely (14%) and long-term (12%). One patient developed a grade II generalized seizure disorder and two others had mild neurologic deficits. Conclusions: High-risk AVMs can be safely treated with hypofractionated PSRS, although complete obliteration rate is low. Future studies should include a possible multi-staged PSRS approach for lesions more resistant to obliteration with radiation. Author Disclosure: H.A. Shih: None. J.A. Hattangadi: None. P.H. Chapman: None. M.R. Bussiere: None. A. Niemierko: None. C.S. Ogilvy: None. A. Rowell: None. J. Daartz: None. J.S. Loeffler: None.
2894
Proton Radiosurgery for Arteriovenous Malformations of Small-to-Intermediate Size
C. R. Sila, R. Schulte, R. Levy, J. D. Slater, J. M. Slater Loma Linda University, San Bernardino, CA Purpose/Objective(s): To assess the treatment results of proton radiosurgery for inoperable arteriovenous malformation (AVMs) up to 15 cc in volume. Materials/Methods: We conducted a retrospective chart review of all patients treated for AVMs with proton radiosurgery in the Loma Linda University Department of Radiation Medicine. Cases that met the following criteria were considered for analysis: no
S638
2892
Volume 81, Number 2, Supplement, 2011
Hypofractionated Stereotactic Radiosurgery for Cerebral AVMs: A Preliminary Report on Bleeding Risk and Obliteration Rate
S. C. Blamek1, D. Larysz2, L. Miszczyk1, A. Rudnik2, A. Idasiak3, K. Ficek1, R. Tarnawski3 1
Department of Radiotherapy, Maria Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, Gliwice Branch, Gliwice, Poland, 2Department of Neurosurgery, Silesian University of Medicine, Katowice, Poland, 3Maria Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, Gliwice Branch, Gliwice, Poland Purpose/Objective(s): Stereotactic radiosurgery is a widely accepted method of treatment for small, surgically inaccessible arteriovenous malformations (AVMs) of the brain. Treatment of large AVMs however is more complicated because of dose-limiting volume of the lesion. Staged-volume or hypofractionated radiosurgery can be the way to deliver a curative dose to an AVM without significantly increased risk of radiation-induced damage. The aim of our study is to assess the safety and efficiency of hypofractionated radiosurgery for large brain AVMs or lesions located in eloquent areas of the brain with special regard to obliteration rates and bleeding risk after the treatment. Materials/Methods: Of 126 patients treated for brain AVMs between 2001 and 2009, forty-nine had hypofractionated stereotactic radiosurgery. There were 25 males and 24 females, mean age was 36 and ranged between 14 and 71 years. Mean and median volume of the lesions were 25.07 and 18.05 ccm, respectively and ranged between 0.36 - 153.98 ccm. Mean dose was 19.9 Gy and ranged between 12 and 28 Gy delivered in 2 - 4 fractions. Mean and median follow-up time was 28.9 and 23.8 months, respectively. Actuarial obliteration rates and annual bleeding hazard were calculated using Kaplan-Meier survival analysis and lifetables. Results: Two patients bled after the treatment, both within 6 months after irradiation. Annual bleeding hazard rates were 4.5%, 1.6% and 2.6% after one, two and 3 years of follow-up, respectively. In one patient significant neurological deterioration (right hemiparesis) was observed after hemorrhage. Actuarial obliteration rates were 7%, 11% and 21% after one, two and three years of follow-up, respectively. Two patients experienced transient neurological deterioration requiring hospitalization, another four had transient neurological symptoms which resolved without treatment. No new permanent neurological deficits that could be attributed to irradiation were observed. Conclusions: Obliteration rates after hypofractionated radiosurgery for brain AVMs are low but reliable estimation requires longer follow-up. Bleeding risk is highest within the first year after the treatment. Hypofractionated radiosurgery is not associated with a significant risk of permanent neurological deficits. Author Disclosure: S.C. Blamek: None. D. Larysz: None. L. Miszczyk: None. A. Rudnik: None. A. Idasiak: None. K. Ficek: None. R. Tarnawski: None.
2893
Two-fraction Proton Beam Stereotactic Radiosurgery For High-Risk Inoperable Cerebral Arteriovenous Malformations (AVMs)
H. A. Shih1, J. A. Hattangadi2, P. H. Chapman1, M. R. Bussiere1, A. Niemierko1, C. S. Ogilvy1, A. Rowell1, J. Daartz1, J. S. Loeffler1 1
Massachusetts General Hospital, Boston, MA, 2Harvard Radiation Oncology Program, Boston, MA
Purpose/Objective(s): To evaluate patients with high-risk cerebral AVMs (eloquent brain location or large size) who underwent two-staged proton stereotactic radiosurgery (PSRS). Materials/Methods: From 1991 - 2009, 59 patients with high-risk cerebral AVMs received two-staged PSRS. Median nidus volume was 23cc (range 1.4 - 58.1 cc), 70% of cases had nidus volume $ 14cc, and 34% were in critical locations (brainstem, basal ganglia). Median modified radiosurgery score, calculated by: (0.1)(nidus volume, cc) + (0.02) (age, years) + (0.5) (location; frontal/temporal/parietal/occipital/ intraventricular/corpus callosum/cerebellar = 0, basal ganglia/thalamus/brainstem = 1) was 3.19 (range 0.9 - 6.9). Many patients had prior surgery or embolization (40%) or prior PSRS (12%). The most common prescription was 16 Gy radiobiologic equivalent (Gy[RBE]) in two fractions, prescribed to the 90% isodose. Results: At a median follow-up of 56.1 months, 9 patients (15%) had complete and 20 (34%) had partial obliteration. Patients with complete obliteration received higher total dose than those with partial or no obliteration (mean dose 17.6 vs. 15.5, p = 0.01). Median time to complete obliteration was 62 months (range 23 - 109) and 5-year actuarial rate of partial or complete obliteration was 33%. Five-year actuarial rate of hemorrhage was 22% (95% CI 12.5 - 36.8%) and 14% (n = 8) suffered fatal hemorrhage. Lesions with higher AVM scores were more likely to hemorrhage (p = 0.024) and less responsive to radiation (p = 0.026). The most common complication was grade I headache acutely (14%) and long-term (12%). One patient developed a grade II generalized seizure disorder and two others had mild neurologic deficits. Conclusions: High-risk AVMs can be safely treated with hypofractionated PSRS, although complete obliteration rate is low. Future studies should include a possible multi-staged PSRS approach for lesions more resistant to obliteration with radiation. Author Disclosure: H.A. Shih: None. J.A. Hattangadi: None. P.H. Chapman: None. M.R. Bussiere: None. A. Niemierko: None. C.S. Ogilvy: None. A. Rowell: None. J. Daartz: None. J.S. Loeffler: None.
2894
Proton Radiosurgery for Arteriovenous Malformations of Small-to-Intermediate Size
C. R. Sila, R. Schulte, R. Levy, J. D. Slater, J. M. Slater Loma Linda University, San Bernardino, CA Purpose/Objective(s): To assess the treatment results of proton radiosurgery for inoperable arteriovenous malformation (AVMs) up to 15 cc in volume. Materials/Methods: We conducted a retrospective chart review of all patients treated for AVMs with proton radiosurgery in the Loma Linda University Department of Radiation Medicine. Cases that met the following criteria were considered for analysis: no