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Gamma-knife Stereotactic Radiosurgery for Non-benign Meningioma
S276
International Journal of Radiation Oncology Biology Physics
2151
and 2000 Hz. Hearing preservation was based on PTA and SD with rates calculated from the date of GK. Serviceable hearing was defined as PTA < 50 dB and SD > 50%. Actuarial rates of hearing loss were calculated using the Kaplan Meier method. Univariate analyses were performed using Fisher’s exact and log rank. Results: With a median audiological follow up of 24 mos (4- 49 mos) the 1-, 2-, and 3-y actuarial rates of maintaining serviceable hearing were 92%, 82% and 82%, respectively. The median cochlear max and mean doses were 6.9 Gy (1.6-16 Gy) and 2.7 Gy (0.7-5.0 Gy), respectively. Patients who received a mean cochlear dose < 3 Gy had a 2-y serviceable hearing preservation rate of 90% compared to 67% in those who received a mean cochlear dose 3 Gy (p Z 0.045). On univariate analysis, use of source plugging to limit cochlear dose was also associated with higher hearing preservation (p < 0.01 for plugs vs none). Two-year hearing preservation was 92% (plugs) vs 61% (none), p Z 0.091. There was no correlation between serviceable hearing loss and age, tumor size or volume, pre-GK PTA, pre-GK SD, pre-GK Garden-Robertson class, GK conformality index, max cochlear dose, or the % cochlear volume receiving 3 or 5 Gy (V3 and V5). Local control was 100% at 24 mos. No patient developed facial or trigeminal nerve dysfunction. Conclusions: Three years after GK radiosurgery, 82% of baseline serviceable hearing patients retained serviceable hearing in this study where the median mean cochlear dose was only 2.7 Gy. A mean cochlear dose < 3 Gy and source plugging were associated with higher hearing preservation rates. Author Disclosure: I.S. Grills: K. Stock; Gamma Knife. A. Baschnagel: None. D. Bojrab: K. Stock; Gamma Knife. D. Pieper: K. Stock; Gamma Knife. J. Kartush: K. Stock; Gamma Knife. O. Didyuk: None. I. Naumann: None. A. Maitz: None. P.Y. Chen: K. Stock; Gamma Knife.
Gamma-knife Stereotactic Radiosurgery for Non-benign Meningioma Y. Mori,1 T. Takahiko,2 T. Kobayashi,2 C. Hashizume,2 and Y. Shibamoto1; 1 Department of Radiology and Radiation Oncology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan, 2Nagoya Radiosurgery Center, Nagoya Kyoritsu Hospital, Nagoya, Japan Purpose/Objective(s): Non-benign meningioma has a tendency to recur repeatedly. The results of Gamma-knife stereotactic radiosurgery (GKS) for recurrent or residual WHO grade 2 and grade 3 meningioma are reported. Materials/Methods: Thirty patients (13 males and 17 females) with WHO grade 2 (24 cases) or WHO grade 3 (6 cases) intracranial meningioma underwent GKS. Their age varied from 30 to 86 years (mean, 64 years). Location of the tumor was convexital in 6, parasagittal in 13, tentorial in 3, and skull base in 3. Before GKS, surgical resection of the tumor was done in all patients, whereas 11 of them also underwent conventional external beam radiation therapy, LINAC-based stereotactic radiation therapy (SRT), or intensity-modulated radiation therapy. At the time of the initial GKS in total 36 intracranial tumors were treated (from 1 to 3 per patient; median, 1). Their volume varied from 0.4 cc to 35.3 cc (median, 8.6 cc). The marginal irradiation dose varied from 11 Gy to 20.15 Gy (mean, 16.7 Gy). Choice of the marginal irradiation dose depended on the tumor volume and its spatial relationship with adjacent anatomical structures, particularly, cranial nerves. Results: Twenty-five out of 30 patients were followed after initial GKS within a median period of 29 months (from 2 to 135 months). Local tumor control after treatment was 76% at 1 year, 61% at 2 years, and 41% at 3 years. Due to local or distant intracranial tumor progression, 15 patients underwent repeat GKS (from 1 to 9 times), 7 underwent surgical reresection of the neoplasm, and 4 underwent additional SRT. At the time of the last follow-up 23 patients were alive, while 2 died. One of the latter expired due to brain tumor progression at 91 months after initial GKS, whereas another one from lung cancer. Conclusions: While non-benign meningioma has a trend to recur repeatedly, aggressive tumor management with repeat GKS at the time of progression can provide long survival of patients. Author Disclosure: Y. Mori: None. T. Takahiko: None. T. Kobayashi: None. C. Hashizume: None. Y. Shibamoto: None.
2152 Mean Cochlear Dose Predicts Hearing Preservation in Acoustic Neuroma Patients Treated With Gamma-knife Stereotactic Radiosurgery I.S. Grills, A. Baschnagel, D. Bojrab, D. Pieper, J. Kartush, O. Didyuk, I. Naumann, A. Maitz, and P.Y. Chen; Beaumont Health System, Royal Oak, MI Purpose/Objective(s): To evaluate hearing preservation in acoustic neuroma patients treated with Gamma-knife (GK) stereotactic radiosurgery. Materials/Methods: Of 114 patients with acoustic neuroma treated with GK between January 2007 and March 2011, 40 with baseline serviceable hearing and prospective follow-up data were evaluated. Median patient age was 59y (26-80y). Sixty-eight percent of patients were Gardner Robertson (GR) Grade 1 pre-GK, 32% GR Grade 2. Median Pure-Tone Average (PTA) pre-GK was 28 dB (3-48dB), median Speech Discrimination (SD) 95% (55-100%). Median max tumor dimension was 1.3cm (0.15-2.46cm); median tumor volume was 0.29 cc (0.05-4.3cc). The median marginal tumor dose was 12.5 Gy (12.5-13 Gy) to the 50% isodose volume. The cochlea and labyrinth were outlined by an experienced neurologist or skull-base neurosurgeon at the time of planning in all cases. Plugging was used to block selected GK sources and limit the cochlear dose in 70% of cases. Audiometry was performed prospectively before and after GK at 1, 3, and 6 months, and then every 6 months thereafter. PTA was calculated with air conduction at 500 Hz, 1000 Hz
2153 Short Course Radiation Therapy for Acoustic Neuromas A. Johnson,1 A.N. Ali,2 A. Dhabbaan,2 X. Jiang,2 H. Shu,2 W. Curran,2 and I. Crocker2; 1Emory University School of Medicine, Atlanta, GA, 2 Department of Radiation Oncology and Winship Cancer Institute, Emory University, Atlanta, GA Purpose/Objective(s): To review the outcomes for older patients (age > 60) with acoustic neuromas treated with short course radiation therapy (XRT). Materials/Methods: A retrospective review was performed of patients treated between December 2002 and November 2010 for acoustic neuromas with a course of 30 Gy in 10 fractions. Patients were generally treated with short course radiation therapy if they were not candidates for single fraction radiosurgery due to tumor size or invagination of the brainstem by tumor. Treatment consisted of either fractionated stereotactic radiation therapy or intensity modulated radiation therapy with daily image guidance. The usual GTV to PTV margin was 2-3 mm. Tumor response was determined by magnetic resonance (MRI) imaging. Toxicities were graded based on the Common Terminology Criteria for Adverse Events (CTCAE) version 4.0. Progression free survival (PFS) and overall survival (OS) were calculated using a Kaplan-Meier analysis. Results: Select demographic and tumor response data are shown in the Table. Thirty patients were identified of which 1 was lost to follow-up. Of the remaining 29 patients, mean follow-up time was 36.6 months (1 to 96 mos). Four patients had prior surgery (13%). The mean delay between surgery and radiation therapy was 76.0 mos. (2.7 to 200.4 mos). The mean planning tumor volume (PTV) was 10.6 cc (0.1 to 35.2 cc). The 5-year actuarial PFS was 0.890.11. The 5-year OS was 0.930.07. There were no secondary malignancies after XRT. There were no grade 2 or greater acute toxicities. Late toxicities included grade 2 and grade 3 ocular dysfunction (2 cases [7%] and 3 cases [10%] respectively), 2 cases of grade 3 hydrocephalus (7%), 3 cases of grade 2 gait disturbance (10%), 2 cases of grade 2 dizziness (7%), 1 case of grade 2 facial nerve disorder (3%) and 1 case of radionecrosis (3%). The grade 3 cases of ocular dysfunction required cataract surgery. Both patients with hydrocephalus received ventriculoperitoneal shunts with full symptom resolution in one
International Journal of Radiation Oncology Biology Physics
2151
and 2000 Hz. Hearing preservation was based on PTA and SD with rates calculated from the date of GK. Serviceable hearing was defined as PTA < 50 dB and SD > 50%. Actuarial rates of hearing loss were calculated using the Kaplan Meier method. Univariate analyses were performed using Fisher’s exact and log rank. Results: With a median audiological follow up of 24 mos (4- 49 mos) the 1-, 2-, and 3-y actuarial rates of maintaining serviceable hearing were 92%, 82% and 82%, respectively. The median cochlear max and mean doses were 6.9 Gy (1.6-16 Gy) and 2.7 Gy (0.7-5.0 Gy), respectively. Patients who received a mean cochlear dose < 3 Gy had a 2-y serviceable hearing preservation rate of 90% compared to 67% in those who received a mean cochlear dose 3 Gy (p Z 0.045). On univariate analysis, use of source plugging to limit cochlear dose was also associated with higher hearing preservation (p < 0.01 for plugs vs none). Two-year hearing preservation was 92% (plugs) vs 61% (none), p Z 0.091. There was no correlation between serviceable hearing loss and age, tumor size or volume, pre-GK PTA, pre-GK SD, pre-GK Garden-Robertson class, GK conformality index, max cochlear dose, or the % cochlear volume receiving 3 or 5 Gy (V3 and V5). Local control was 100% at 24 mos. No patient developed facial or trigeminal nerve dysfunction. Conclusions: Three years after GK radiosurgery, 82% of baseline serviceable hearing patients retained serviceable hearing in this study where the median mean cochlear dose was only 2.7 Gy. A mean cochlear dose < 3 Gy and source plugging were associated with higher hearing preservation rates. Author Disclosure: I.S. Grills: K. Stock; Gamma Knife. A. Baschnagel: None. D. Bojrab: K. Stock; Gamma Knife. D. Pieper: K. Stock; Gamma Knife. J. Kartush: K. Stock; Gamma Knife. O. Didyuk: None. I. Naumann: None. A. Maitz: None. P.Y. Chen: K. Stock; Gamma Knife.
Gamma-knife Stereotactic Radiosurgery for Non-benign Meningioma Y. Mori,1 T. Takahiko,2 T. Kobayashi,2 C. Hashizume,2 and Y. Shibamoto1; 1 Department of Radiology and Radiation Oncology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan, 2Nagoya Radiosurgery Center, Nagoya Kyoritsu Hospital, Nagoya, Japan Purpose/Objective(s): Non-benign meningioma has a tendency to recur repeatedly. The results of Gamma-knife stereotactic radiosurgery (GKS) for recurrent or residual WHO grade 2 and grade 3 meningioma are reported. Materials/Methods: Thirty patients (13 males and 17 females) with WHO grade 2 (24 cases) or WHO grade 3 (6 cases) intracranial meningioma underwent GKS. Their age varied from 30 to 86 years (mean, 64 years). Location of the tumor was convexital in 6, parasagittal in 13, tentorial in 3, and skull base in 3. Before GKS, surgical resection of the tumor was done in all patients, whereas 11 of them also underwent conventional external beam radiation therapy, LINAC-based stereotactic radiation therapy (SRT), or intensity-modulated radiation therapy. At the time of the initial GKS in total 36 intracranial tumors were treated (from 1 to 3 per patient; median, 1). Their volume varied from 0.4 cc to 35.3 cc (median, 8.6 cc). The marginal irradiation dose varied from 11 Gy to 20.15 Gy (mean, 16.7 Gy). Choice of the marginal irradiation dose depended on the tumor volume and its spatial relationship with adjacent anatomical structures, particularly, cranial nerves. Results: Twenty-five out of 30 patients were followed after initial GKS within a median period of 29 months (from 2 to 135 months). Local tumor control after treatment was 76% at 1 year, 61% at 2 years, and 41% at 3 years. Due to local or distant intracranial tumor progression, 15 patients underwent repeat GKS (from 1 to 9 times), 7 underwent surgical reresection of the neoplasm, and 4 underwent additional SRT. At the time of the last follow-up 23 patients were alive, while 2 died. One of the latter expired due to brain tumor progression at 91 months after initial GKS, whereas another one from lung cancer. Conclusions: While non-benign meningioma has a trend to recur repeatedly, aggressive tumor management with repeat GKS at the time of progression can provide long survival of patients. Author Disclosure: Y. Mori: None. T. Takahiko: None. T. Kobayashi: None. C. Hashizume: None. Y. Shibamoto: None.
2152 Mean Cochlear Dose Predicts Hearing Preservation in Acoustic Neuroma Patients Treated With Gamma-knife Stereotactic Radiosurgery I.S. Grills, A. Baschnagel, D. Bojrab, D. Pieper, J. Kartush, O. Didyuk, I. Naumann, A. Maitz, and P.Y. Chen; Beaumont Health System, Royal Oak, MI Purpose/Objective(s): To evaluate hearing preservation in acoustic neuroma patients treated with Gamma-knife (GK) stereotactic radiosurgery. Materials/Methods: Of 114 patients with acoustic neuroma treated with GK between January 2007 and March 2011, 40 with baseline serviceable hearing and prospective follow-up data were evaluated. Median patient age was 59y (26-80y). Sixty-eight percent of patients were Gardner Robertson (GR) Grade 1 pre-GK, 32% GR Grade 2. Median Pure-Tone Average (PTA) pre-GK was 28 dB (3-48dB), median Speech Discrimination (SD) 95% (55-100%). Median max tumor dimension was 1.3cm (0.15-2.46cm); median tumor volume was 0.29 cc (0.05-4.3cc). The median marginal tumor dose was 12.5 Gy (12.5-13 Gy) to the 50% isodose volume. The cochlea and labyrinth were outlined by an experienced neurologist or skull-base neurosurgeon at the time of planning in all cases. Plugging was used to block selected GK sources and limit the cochlear dose in 70% of cases. Audiometry was performed prospectively before and after GK at 1, 3, and 6 months, and then every 6 months thereafter. PTA was calculated with air conduction at 500 Hz, 1000 Hz
2153 Short Course Radiation Therapy for Acoustic Neuromas A. Johnson,1 A.N. Ali,2 A. Dhabbaan,2 X. Jiang,2 H. Shu,2 W. Curran,2 and I. Crocker2; 1Emory University School of Medicine, Atlanta, GA, 2 Department of Radiation Oncology and Winship Cancer Institute, Emory University, Atlanta, GA Purpose/Objective(s): To review the outcomes for older patients (age > 60) with acoustic neuromas treated with short course radiation therapy (XRT). Materials/Methods: A retrospective review was performed of patients treated between December 2002 and November 2010 for acoustic neuromas with a course of 30 Gy in 10 fractions. Patients were generally treated with short course radiation therapy if they were not candidates for single fraction radiosurgery due to tumor size or invagination of the brainstem by tumor. Treatment consisted of either fractionated stereotactic radiation therapy or intensity modulated radiation therapy with daily image guidance. The usual GTV to PTV margin was 2-3 mm. Tumor response was determined by magnetic resonance (MRI) imaging. Toxicities were graded based on the Common Terminology Criteria for Adverse Events (CTCAE) version 4.0. Progression free survival (PFS) and overall survival (OS) were calculated using a Kaplan-Meier analysis. Results: Select demographic and tumor response data are shown in the Table. Thirty patients were identified of which 1 was lost to follow-up. Of the remaining 29 patients, mean follow-up time was 36.6 months (1 to 96 mos). Four patients had prior surgery (13%). The mean delay between surgery and radiation therapy was 76.0 mos. (2.7 to 200.4 mos). The mean planning tumor volume (PTV) was 10.6 cc (0.1 to 35.2 cc). The 5-year actuarial PFS was 0.890.11. The 5-year OS was 0.930.07. There were no secondary malignancies after XRT. There were no grade 2 or greater acute toxicities. Late toxicities included grade 2 and grade 3 ocular dysfunction (2 cases [7%] and 3 cases [10%] respectively), 2 cases of grade 3 hydrocephalus (7%), 3 cases of grade 2 gait disturbance (10%), 2 cases of grade 2 dizziness (7%), 1 case of grade 2 facial nerve disorder (3%) and 1 case of radionecrosis (3%). The grade 3 cases of ocular dysfunction required cataract surgery. Both patients with hydrocephalus received ventriculoperitoneal shunts with full symptom resolution in one