- Email: [email protected]
Analysis of Treatment Utilization in Patients With Low-Grade Gliomas Using Data From the National Cancer Data Base (NCDB)
Volume 96 Number 2S Supplement 2016
Poster Viewing E111 94 new mets from 0-6 months (early). At 6-12 months (late), 19 out of 29 patients alive developed 78 new mets. In total, 172 new brain mets were identified, 16 of which were symptomatic (9.3%). These 16 mets, identified in 8 patients, demonstrated neurological symptoms related to the location of the new tumor (Table 1). Conclusion: Our study showed that following initial radiation treatment, most new brain mets are asymptomatic (90.7%) when identified on routine MRI. This suggests that distant tumor control might play a less significant role in the initial radiation choice, since these new brain mets can be treated before becoming symptomatic. Further, this could support delaying or avoiding WBRT in favor of upfront SRS, in order to reduce toxicity and promote better quality of life. A prospective trial is currently in progress.
that original RTOG-RPA and BSBM had correlation with prognosis. Median survival for Original RTOG-RPA classes 1, 2, and 3 was 10.4 months, 11 months, and 8.7 months respectively (P Z 0.0094). Median survival for BSBM classes 0, 1, 2, and 3 was 7.8 months, 10.4 months, 16.7 months and 7.6 months respectively (P Z 0.0322). Other prognostic indices didn’t relate to survival. Conclusion: Original RTOG-RPA and BSBM correlated well with prognosis of the Japanese patients with brain metastases in our hospital. Author Disclosure: A. Niiya: None. K. Murakami: None. R. Kobayashi: None. M. Kato: None. N. Okabe: None. M. Obinata: None. Y. Ozawa: None. M. Morota: None. H. Shinjo: None. Y. Kagami: None.
2271
Abstract 2271; Table 1. Symptomatology of the 16 new symptomatic brain mets in patients (n [ 8). Seven types of symptoms were experienced and in some cases patients had multiple symptoms. Severity of symptoms ranged from mild to severe.
Retrospective Analysis to Determine the Frequency of Symptomatic New Brain Metastases During Routine Magnetic Resonance Imaging Surveillance Following Stereotactic Radiosurgery or Whole-Brain Radiation Therapy D.R. Eichorn,1 M.U. Ali,1 A. Lesenskyj,1 A. Potts,1 V. Trivedi,1 R. Patchell,2 T.H. Chen,2 S. Williamson,2 C.R. Maxwell,1 and A. Mintz2; 1 Capital Health Medical Center - Regional, Trenton, NJ, 2Capital Health Medical Center - Hopewell, Pennington, NJ Purpose/Objective(s): Initial use of stereotactic radiosurgery (SRS) for treatment of brain metastases (mets) has been questioned due to higher failure rate of distant control compared to whole-brain radiation therapy (WBRT). WBRT has been shown to be associated with increased toxicity and cognitive decline, yet overall survival (OS) rates are similar. Whether high rates of distant control failure with SRS should be a chief consideration in choice of radiation technique, depends on whether the new mets are symptomatic when identified through routine MRI screening. This review aims to determine the proportion of new brain mets that are symptomatic following initial radiation treatment, as a way to provide valuable insight for making an initial treatment decision. We hypothesize that the majority of new brain mets are asymptomatic. Materials/Methods: From 2012-2015, 115 consecutive charts of patients treated with SRS, WBRT or both were reviewed for development of new mets during the first year after treatment. Serial MRIs occurred every 3 months. Chart reviewers and statisticians were blinded to the hypothesis. Data collected at each interval included MRI review, neurological and general symptoms, and treatment modalities. Results: Median patient age was 64.6 years, with 43% being male and 57% female. Frequent primary tumors were lung (49.5%), breast (15.1%), colon (6.1%), melanoma (6.1%), and renal (6.1%). Mean OS was 9.8 months. Following initial treatment, 30 out of 46 patients alive developed
Symptom
Number of patients with symptom
Aphasia Ataxia Cognitive decline Focal weakness Headache Numbness and tingling Vision changes
1 1 1 4 2 1 2
Author Disclosure: D.R. Eichorn: None. M.U. Ali: None. A. Lesenskyj: None. A. Potts: None. V. Trivedi: None. R. Patchell: None. T.H. Chen: None. S. Williamson: None. C.R. Maxwell: None. A. Mintz: None.
2272 Analysis of Treatment Utilization in Patients With Low-Grade Gliomas Using Data From the National Cancer Data Base (NCDB) T. Gunter1 and O. Algan2; 1College of Medicine University of Oklahoma Health Sciences Center, Oklahoma City, OK, 2University of Oklahoma Health Sciences Center, Oklahoma City, OK Purpose/Objective(s): To evaluate clinicopathologic factors associated with treatment utilization for patients with low grade gliomas (LGG). Materials/Methods: The NCDB is a comprehensive national database that captures approximately 70% of newly diagnosed cancer patients in the US. Data for patients meeting the criteria for LGG (WHO Grade II) were extracted from the NCDB from 2004-2013. Patients with available data
Abstract 2272; Table 1.
Differentiation Tumor diameter Age Histology Underwent surgery # of adverse prognostic features
Insurance status
Well-differentiated Moderately-differentiated <6 cm 6 cm <40 years 40 years Non-astrocytoma Astrocytoma Yes No 0 1 2 3 Insured Uninsured
Surgery
Radiation Therapy
Chemotherapy
Combination
NS NS NS NS 81.3% 68.8% 64.7% 82.9%
30.1% 39.9% 34.3% 45.3% 30.6% 43.4% 31.8% 44.3% 32.6% 52.1% 24.7% 33.2% 49.2% 48.7% NS NS
28.3% 34.1% 29.0% 39.9% 29.2% 35.6% 34.9% 30.1% 23.1% 41.5% 27.0%* 31.4%* 32.9%* 36.5%* NS NS
14.2% 18.8% 15.3% 24.1% 14.2% 20.6% 15.8% 19.8% 15.0% 25.6% 10.8% 16.0% 22.4% 24.3% 18.3%y 14.1%y
87.5% 82.1% 67.0% 55.7% NS NS
Combination: chemotherapy and radiation therapy NS: nonsignificant difference *: P [ 0.037 y: P [ 0.049.
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International Journal of Radiation Oncology Biology Physics
were included in a given analysis. Statistical analysis was performed using chi-square test on predictive analytics software. All comparisons between groups were statistically significant (P<0.001) unless noted otherwise. Results: A total of 5093 patients with LGG were identified within the NCDB. Table 1 shows treatment utilization by various clinicopathologic factors. In general, patients were more likely to receive chemotherapy and/ or radiation therapy when they had higher risk features, or multiple poor prognostic features. Patients were also more likely to receive chemotherapy and/or radiation therapy if they did not undergo surgical resection. There were no significant differences in treatment modality utilized when patients were grouped by race or sex. Patients with insurance received a combination of chemotherapy and radiation therapy more frequently than uninsured patients. Conclusion: In general, our analysis of a large national database supports treatment utilization consistent with EORTC prognostic criteria. The data show that in addition to the other established criteria the degree of differentiation also contributes to management decisions. Although our analysis has limitations including a hospital-based data set, missing data, and potential for misclassification, it does represent one of the largest patient populations for a relatively uncommon tumor. Author Disclosure: T. Gunter: None. O. Algan: None.
Author Disclosure: L.M. Katz: None. R. Sen: None. G. Fatterpekar: None. J.S. Silverman: None. B. Liechty: None. M. Snuderl: None. J. Golfinos: None. D. Pacione: None. C. Sen: None.
2273 Evaluation of Radiological Meningioma Margin is Superior to CSF Cleft in Predicting Surgical Ease L.M. Katz,1 R. Sen,2 G. Fatterpekar,2 J.S. Silverman,3 B. Liechty,2 M. Snuderl,2 J. Golfinos,2 D. Pacione,4 and C. Sen2; 1NYU School of Medicine and NYU Langone Medical Center, Department of Radiation Oncology, Medicine, and Surgery, New York, NY, 2NYU Langone Medical Center, New York, NY, 3Department of Radiation Oncology, NYU Langone Medical Center, New York, NY, 4NYU Langone Medical Center, New York, NY Purpose/Objective(s): Presence of CSF-cleft on MRI T2-weighted images (T2-WI) is considered an imaging hallmark of an extra-axial mass. Presence of such a cleft is thought to represent a clear arachnoid plane between the mass and underlying brain predicting resection ease. Meningioma, the most common extra-axial lesion is often treated by surgical excision. Occasionally, at the time of surgery, separating meningioma from underlying brain becomes difficult. The purpose of our study was to evaluate imaging features that will predict the ease or difficulty of surgical excision in meningioma patients demonstrating a clear CSF-cleft on preoperative MRI scans. Materials/Methods: A retrospective, IRB-approved, HIPAA compliant study was performed in 11 consecutive meningioma cases in whom separating meningioma from brain proved difficult despite demonstrating a clear CSF-cleft on pre-operative MRI scans. All scans were performed on 3.0T MRI scanners. Imaging sequences included T2-WI, diffusionweighted images (DWI), and contrast-enhanced MPRAGE sequences. T2WI confirmed presence of CSF cleft along meningioma circumference. DWI assessed diffusion restriction utilizing apparent diffusion coefficient (ADC) maps, and FLAIR images assessed peri-tumoral brain edema. Contrast-enhanced MPRAGE sequences were utilized to evaluate margin of meningiomas. These margins were graded as Grade I: smooth without lobulation, Grade II: smooth with large lobulations, Grade III: irregular with microlobulations. Results: All 11 cases demonstrated a clear circumferential CSF-cleft on T2WI. Varying ADC values (n Z 6 restricted diffusion, n Z 5 facilitated diffusion) were noted. Seven of 11 cases demonstrated peritumoral edema. All 11 patients demonstrated Grade III margin. There were no Grade I or II margin types. Conclusion: Presence of an irregularly marginated meningioma predicts a difficult surgical plane between the lesion and underlying brain, despite the presence of a clear CSF-cleft on T2-WI. Such pre-operative tumoral margin evaluation therefore provides critical information allowing for better surgical planning, and thus, improved outcomes.
2274 The Role of Adjuvant Radiation Therapy in Patients With Myxopapillary Ependymomas R. Kotecha,1 S. Modugula,1 L. Angelov,2 E.C. Benzel,2 C.A. Reddy,1 R. Prayson,1 I. Kalfas,1 R. Schlenk,1 A. Krishnaney,1 M. Steinmetz,1 W. Bingaman,1 J.H. Suh,3 and S.T. Chao3; 1Cleveland Clinic, Cleveland, OH, 2Department of Neurosurgery, Cleveland Clinic, Cleveland, OH, 3 Department of Radiation Oncology, Cleveland Clinic, Cleveland, OH Purpose/Objective(s): The role of adjuvant radiation therapy (RT) for myxopapillary ependymomas (MPE) is controversial. The objectives of the present study were to characterize the natural history, patterns and timing of recurrences, and outcomes by treatment. Materials/Methods: The records of 59 patients with a histologically verified diagnosis of spinal MPE were reviewed. Recurrence and survival times were calculated using the Kaplan-Meier method and Cox proportional hazards regression analysis determined contributing factors to recurrence risk. Results: The median age at time of diagnosis was 34 years (Range [R]: 1274 years) and the median follow-up from the time of initial surgery was 74.4 months (R: 0-423.3 months). At the time of initial diagnosis, 49 patients (83%) underwent surgery; 10 patients (17%) underwent adjuvant RT (5 patients after gross total resection [GTR] and 5 patients after subtotal resection [STR]) to a median dose of 49 Gy (45-58 Gy) delivered via conventional fractionation. The 5 and 10-year recurrence free survivals (RFSs) were 75.4% (95% CI: 62.6-88.3%) and 54.7% (37.5-71.8%). The 5-year RFS was 86.3% (95% CI: 73.6-99.0%) after GTR versus 50.3% (95% CI: 21.5-79.1%) after STR. The median RFS was longer in patients who underwent a GTR compared to STR (205.9 vs 65.5 months, P<0.0001). On univariate analysis, a STR was associated with a higher risk of recurrence (HR: 6.45, 95% CI: 2.15-19.23). Adjuvant RT did not significantly improve the RFS after GTR (134.3 vs 205.9 months, P Z 0.92) or STR (35.1 vs 110.2 months, P Z 0.27). Overall, 20 patients (34%) had a recurrence: 15 patients (75% of this subgroup) had a local recurrence and five patients (25% of this subgroup) had a distant recurrence. For both of these groups, recurrences primarily occurred within the first two years after diagnosis. The most common treatment after initial recurrence was surgery alone (12 patients, 60% of which most underwent GTR or STR), followed by RT with (4 patients, 20%) or without (4 patients, 20%) surgery. Adjuvant RT at the time of initial recurrence was associated with a significantly longer RFS (114.6 months vs 18.9 months, P<0.006). The 5year RFS was 73.0% (95% CI: 58.3-87.6%) and 86.7% (95% CI: 62.3100%) for those patients treated with surgery alone compared to combined modality therapy. Conclusion: Patients with MPE remain at risk for local and distant recurrences after initial treatment and given the long natural history, should undergo routine follow-up. Patients are optimally managed with a GTR in the upfront setting. Although the majority of patients managed in the upfront setting with surgery alone remain at risk for local recurrence in the first two years, the benefit of adjuvant RT remains undetermined. At the time of re-resection for recurrence, patients should undergo adjuvant RT. Author Disclosure: R. Kotecha: None. S. Modugula: None. L. Angelov: None. E.C. Benzel: Consult and speaking; Axiomed Spine Corporation, Turning Point Biotechnology. Royalty; Axiomed Spine Corporation, OrthoMEMS, Inc. Royalty and Equity; Sports Safe, LLC. Fiduciary Role; Cervical Spine Research Society and Sports Safe, LLC. C.A. Reddy: None. R. Prayson: None. I. Kalfas: Royalty; Mako Surgical Corp. R. Schlenk: None. A. Krishnaney: None. M. Steinmetz: None. W. Bingaman: Consult and speaking; National Football League. J.H. Suh: Research Grant; Varian Medical Systems. Travel Expenses; Elekta. S.T. Chao: Honoraria; Varian Medical Systems.
Poster Viewing E111 94 new mets from 0-6 months (early). At 6-12 months (late), 19 out of 29 patients alive developed 78 new mets. In total, 172 new brain mets were identified, 16 of which were symptomatic (9.3%). These 16 mets, identified in 8 patients, demonstrated neurological symptoms related to the location of the new tumor (Table 1). Conclusion: Our study showed that following initial radiation treatment, most new brain mets are asymptomatic (90.7%) when identified on routine MRI. This suggests that distant tumor control might play a less significant role in the initial radiation choice, since these new brain mets can be treated before becoming symptomatic. Further, this could support delaying or avoiding WBRT in favor of upfront SRS, in order to reduce toxicity and promote better quality of life. A prospective trial is currently in progress.
that original RTOG-RPA and BSBM had correlation with prognosis. Median survival for Original RTOG-RPA classes 1, 2, and 3 was 10.4 months, 11 months, and 8.7 months respectively (P Z 0.0094). Median survival for BSBM classes 0, 1, 2, and 3 was 7.8 months, 10.4 months, 16.7 months and 7.6 months respectively (P Z 0.0322). Other prognostic indices didn’t relate to survival. Conclusion: Original RTOG-RPA and BSBM correlated well with prognosis of the Japanese patients with brain metastases in our hospital. Author Disclosure: A. Niiya: None. K. Murakami: None. R. Kobayashi: None. M. Kato: None. N. Okabe: None. M. Obinata: None. Y. Ozawa: None. M. Morota: None. H. Shinjo: None. Y. Kagami: None.
2271
Abstract 2271; Table 1. Symptomatology of the 16 new symptomatic brain mets in patients (n [ 8). Seven types of symptoms were experienced and in some cases patients had multiple symptoms. Severity of symptoms ranged from mild to severe.
Retrospective Analysis to Determine the Frequency of Symptomatic New Brain Metastases During Routine Magnetic Resonance Imaging Surveillance Following Stereotactic Radiosurgery or Whole-Brain Radiation Therapy D.R. Eichorn,1 M.U. Ali,1 A. Lesenskyj,1 A. Potts,1 V. Trivedi,1 R. Patchell,2 T.H. Chen,2 S. Williamson,2 C.R. Maxwell,1 and A. Mintz2; 1 Capital Health Medical Center - Regional, Trenton, NJ, 2Capital Health Medical Center - Hopewell, Pennington, NJ Purpose/Objective(s): Initial use of stereotactic radiosurgery (SRS) for treatment of brain metastases (mets) has been questioned due to higher failure rate of distant control compared to whole-brain radiation therapy (WBRT). WBRT has been shown to be associated with increased toxicity and cognitive decline, yet overall survival (OS) rates are similar. Whether high rates of distant control failure with SRS should be a chief consideration in choice of radiation technique, depends on whether the new mets are symptomatic when identified through routine MRI screening. This review aims to determine the proportion of new brain mets that are symptomatic following initial radiation treatment, as a way to provide valuable insight for making an initial treatment decision. We hypothesize that the majority of new brain mets are asymptomatic. Materials/Methods: From 2012-2015, 115 consecutive charts of patients treated with SRS, WBRT or both were reviewed for development of new mets during the first year after treatment. Serial MRIs occurred every 3 months. Chart reviewers and statisticians were blinded to the hypothesis. Data collected at each interval included MRI review, neurological and general symptoms, and treatment modalities. Results: Median patient age was 64.6 years, with 43% being male and 57% female. Frequent primary tumors were lung (49.5%), breast (15.1%), colon (6.1%), melanoma (6.1%), and renal (6.1%). Mean OS was 9.8 months. Following initial treatment, 30 out of 46 patients alive developed
Symptom
Number of patients with symptom
Aphasia Ataxia Cognitive decline Focal weakness Headache Numbness and tingling Vision changes
1 1 1 4 2 1 2
Author Disclosure: D.R. Eichorn: None. M.U. Ali: None. A. Lesenskyj: None. A. Potts: None. V. Trivedi: None. R. Patchell: None. T.H. Chen: None. S. Williamson: None. C.R. Maxwell: None. A. Mintz: None.
2272 Analysis of Treatment Utilization in Patients With Low-Grade Gliomas Using Data From the National Cancer Data Base (NCDB) T. Gunter1 and O. Algan2; 1College of Medicine University of Oklahoma Health Sciences Center, Oklahoma City, OK, 2University of Oklahoma Health Sciences Center, Oklahoma City, OK Purpose/Objective(s): To evaluate clinicopathologic factors associated with treatment utilization for patients with low grade gliomas (LGG). Materials/Methods: The NCDB is a comprehensive national database that captures approximately 70% of newly diagnosed cancer patients in the US. Data for patients meeting the criteria for LGG (WHO Grade II) were extracted from the NCDB from 2004-2013. Patients with available data
Abstract 2272; Table 1.
Differentiation Tumor diameter Age Histology Underwent surgery # of adverse prognostic features
Insurance status
Well-differentiated Moderately-differentiated <6 cm 6 cm <40 years 40 years Non-astrocytoma Astrocytoma Yes No 0 1 2 3 Insured Uninsured
Surgery
Radiation Therapy
Chemotherapy
Combination
NS NS NS NS 81.3% 68.8% 64.7% 82.9%
30.1% 39.9% 34.3% 45.3% 30.6% 43.4% 31.8% 44.3% 32.6% 52.1% 24.7% 33.2% 49.2% 48.7% NS NS
28.3% 34.1% 29.0% 39.9% 29.2% 35.6% 34.9% 30.1% 23.1% 41.5% 27.0%* 31.4%* 32.9%* 36.5%* NS NS
14.2% 18.8% 15.3% 24.1% 14.2% 20.6% 15.8% 19.8% 15.0% 25.6% 10.8% 16.0% 22.4% 24.3% 18.3%y 14.1%y
87.5% 82.1% 67.0% 55.7% NS NS
Combination: chemotherapy and radiation therapy NS: nonsignificant difference *: P [ 0.037 y: P [ 0.049.
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International Journal of Radiation Oncology Biology Physics
were included in a given analysis. Statistical analysis was performed using chi-square test on predictive analytics software. All comparisons between groups were statistically significant (P<0.001) unless noted otherwise. Results: A total of 5093 patients with LGG were identified within the NCDB. Table 1 shows treatment utilization by various clinicopathologic factors. In general, patients were more likely to receive chemotherapy and/ or radiation therapy when they had higher risk features, or multiple poor prognostic features. Patients were also more likely to receive chemotherapy and/or radiation therapy if they did not undergo surgical resection. There were no significant differences in treatment modality utilized when patients were grouped by race or sex. Patients with insurance received a combination of chemotherapy and radiation therapy more frequently than uninsured patients. Conclusion: In general, our analysis of a large national database supports treatment utilization consistent with EORTC prognostic criteria. The data show that in addition to the other established criteria the degree of differentiation also contributes to management decisions. Although our analysis has limitations including a hospital-based data set, missing data, and potential for misclassification, it does represent one of the largest patient populations for a relatively uncommon tumor. Author Disclosure: T. Gunter: None. O. Algan: None.
Author Disclosure: L.M. Katz: None. R. Sen: None. G. Fatterpekar: None. J.S. Silverman: None. B. Liechty: None. M. Snuderl: None. J. Golfinos: None. D. Pacione: None. C. Sen: None.
2273 Evaluation of Radiological Meningioma Margin is Superior to CSF Cleft in Predicting Surgical Ease L.M. Katz,1 R. Sen,2 G. Fatterpekar,2 J.S. Silverman,3 B. Liechty,2 M. Snuderl,2 J. Golfinos,2 D. Pacione,4 and C. Sen2; 1NYU School of Medicine and NYU Langone Medical Center, Department of Radiation Oncology, Medicine, and Surgery, New York, NY, 2NYU Langone Medical Center, New York, NY, 3Department of Radiation Oncology, NYU Langone Medical Center, New York, NY, 4NYU Langone Medical Center, New York, NY Purpose/Objective(s): Presence of CSF-cleft on MRI T2-weighted images (T2-WI) is considered an imaging hallmark of an extra-axial mass. Presence of such a cleft is thought to represent a clear arachnoid plane between the mass and underlying brain predicting resection ease. Meningioma, the most common extra-axial lesion is often treated by surgical excision. Occasionally, at the time of surgery, separating meningioma from underlying brain becomes difficult. The purpose of our study was to evaluate imaging features that will predict the ease or difficulty of surgical excision in meningioma patients demonstrating a clear CSF-cleft on preoperative MRI scans. Materials/Methods: A retrospective, IRB-approved, HIPAA compliant study was performed in 11 consecutive meningioma cases in whom separating meningioma from brain proved difficult despite demonstrating a clear CSF-cleft on pre-operative MRI scans. All scans were performed on 3.0T MRI scanners. Imaging sequences included T2-WI, diffusionweighted images (DWI), and contrast-enhanced MPRAGE sequences. T2WI confirmed presence of CSF cleft along meningioma circumference. DWI assessed diffusion restriction utilizing apparent diffusion coefficient (ADC) maps, and FLAIR images assessed peri-tumoral brain edema. Contrast-enhanced MPRAGE sequences were utilized to evaluate margin of meningiomas. These margins were graded as Grade I: smooth without lobulation, Grade II: smooth with large lobulations, Grade III: irregular with microlobulations. Results: All 11 cases demonstrated a clear circumferential CSF-cleft on T2WI. Varying ADC values (n Z 6 restricted diffusion, n Z 5 facilitated diffusion) were noted. Seven of 11 cases demonstrated peritumoral edema. All 11 patients demonstrated Grade III margin. There were no Grade I or II margin types. Conclusion: Presence of an irregularly marginated meningioma predicts a difficult surgical plane between the lesion and underlying brain, despite the presence of a clear CSF-cleft on T2-WI. Such pre-operative tumoral margin evaluation therefore provides critical information allowing for better surgical planning, and thus, improved outcomes.
2274 The Role of Adjuvant Radiation Therapy in Patients With Myxopapillary Ependymomas R. Kotecha,1 S. Modugula,1 L. Angelov,2 E.C. Benzel,2 C.A. Reddy,1 R. Prayson,1 I. Kalfas,1 R. Schlenk,1 A. Krishnaney,1 M. Steinmetz,1 W. Bingaman,1 J.H. Suh,3 and S.T. Chao3; 1Cleveland Clinic, Cleveland, OH, 2Department of Neurosurgery, Cleveland Clinic, Cleveland, OH, 3 Department of Radiation Oncology, Cleveland Clinic, Cleveland, OH Purpose/Objective(s): The role of adjuvant radiation therapy (RT) for myxopapillary ependymomas (MPE) is controversial. The objectives of the present study were to characterize the natural history, patterns and timing of recurrences, and outcomes by treatment. Materials/Methods: The records of 59 patients with a histologically verified diagnosis of spinal MPE were reviewed. Recurrence and survival times were calculated using the Kaplan-Meier method and Cox proportional hazards regression analysis determined contributing factors to recurrence risk. Results: The median age at time of diagnosis was 34 years (Range [R]: 1274 years) and the median follow-up from the time of initial surgery was 74.4 months (R: 0-423.3 months). At the time of initial diagnosis, 49 patients (83%) underwent surgery; 10 patients (17%) underwent adjuvant RT (5 patients after gross total resection [GTR] and 5 patients after subtotal resection [STR]) to a median dose of 49 Gy (45-58 Gy) delivered via conventional fractionation. The 5 and 10-year recurrence free survivals (RFSs) were 75.4% (95% CI: 62.6-88.3%) and 54.7% (37.5-71.8%). The 5-year RFS was 86.3% (95% CI: 73.6-99.0%) after GTR versus 50.3% (95% CI: 21.5-79.1%) after STR. The median RFS was longer in patients who underwent a GTR compared to STR (205.9 vs 65.5 months, P<0.0001). On univariate analysis, a STR was associated with a higher risk of recurrence (HR: 6.45, 95% CI: 2.15-19.23). Adjuvant RT did not significantly improve the RFS after GTR (134.3 vs 205.9 months, P Z 0.92) or STR (35.1 vs 110.2 months, P Z 0.27). Overall, 20 patients (34%) had a recurrence: 15 patients (75% of this subgroup) had a local recurrence and five patients (25% of this subgroup) had a distant recurrence. For both of these groups, recurrences primarily occurred within the first two years after diagnosis. The most common treatment after initial recurrence was surgery alone (12 patients, 60% of which most underwent GTR or STR), followed by RT with (4 patients, 20%) or without (4 patients, 20%) surgery. Adjuvant RT at the time of initial recurrence was associated with a significantly longer RFS (114.6 months vs 18.9 months, P<0.006). The 5year RFS was 73.0% (95% CI: 58.3-87.6%) and 86.7% (95% CI: 62.3100%) for those patients treated with surgery alone compared to combined modality therapy. Conclusion: Patients with MPE remain at risk for local and distant recurrences after initial treatment and given the long natural history, should undergo routine follow-up. Patients are optimally managed with a GTR in the upfront setting. Although the majority of patients managed in the upfront setting with surgery alone remain at risk for local recurrence in the first two years, the benefit of adjuvant RT remains undetermined. At the time of re-resection for recurrence, patients should undergo adjuvant RT. Author Disclosure: R. Kotecha: None. S. Modugula: None. L. Angelov: None. E.C. Benzel: Consult and speaking; Axiomed Spine Corporation, Turning Point Biotechnology. Royalty; Axiomed Spine Corporation, OrthoMEMS, Inc. Royalty and Equity; Sports Safe, LLC. Fiduciary Role; Cervical Spine Research Society and Sports Safe, LLC. C.A. Reddy: None. R. Prayson: None. I. Kalfas: Royalty; Mako Surgical Corp. R. Schlenk: None. A. Krishnaney: None. M. Steinmetz: None. W. Bingaman: Consult and speaking; National Football League. J.H. Suh: Research Grant; Varian Medical Systems. Travel Expenses; Elekta. S.T. Chao: Honoraria; Varian Medical Systems.