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Effect of Radiation Treatment Volume Reduction on Lymphopenia in Patients Receiving Chemoradiation for Glioblastoma Multiforme
E104
International Journal of Radiation Oncology Biology Physics
Materials/Methods: We identified 149 patients with adenocarcinoma of the lung and newly diagnosed brain metastases without a targetable mutation diagnosed between 2000-2015 who received stereotactic radiation (either stereotactic radiosurgery or hypofractionated stereotactic radiotherapy) at a single institution. Cox regression was used to assess whether patients managed with stereotactic radiation for brain metastases display improved intracranial disease control and higher rates of radiation necrosis when also managed with pemetrexed as systemic therapy. Kaplan-Meier (KM) analysis was used to estimate freedom from radiographic necrosis and freedom from new brain metastases at 1 year. Results: Among the entire cohort, 105 patients received pemetrexed while 44 patients did not. No significant differences in age or performance status were noted between the cohorts. Pemetrexed use was associated with increased radiographic necrosis after stereotactic radiation (pZ0.03). Freedom from radiographic necrosis at 1 year was 75.9% (95% CI, 62.1%-85.3%) for those who received pemetrexed compared to 90.2% (95% CI, 72.3%-96.8%) among those who did not receive pemetrexed. There was a trend towards a higher incidence of radiation necrosis in patients receiving pemetrexed before versus after stereotactic radiation (pZ0.12). Among patients with newly-diagnosed adenocarcinoma of the lung who were chemotherapy-naı¨ve, use of poststereotactic radiation pemetrexed versus all other systemic regimens was associated with a trend to improved distant intracranial control (pZ0.11). At 1 year, freedom from new brain metastases among patients receiving post-stereotactic radiation pemetrexed was 39.0% (95% CI, 26.1%-51.7%) compared to18.3% (95% CI, 2.9%-44.1%) among those who received any other systemic therapy regimen after stereotactic radiation. Conclusion: Results of this retrospective study suggest that stereotactic radiation with pemetrexed administration is associated with an increased risk of radiation necrosis in the brain. Patients receiving pemetrexed may be less likely to develop new brain metastases. Author Disclosure: Z.J. Reitman: None. D.N. Cagney: None. A. Martin: None. S.E. Weiss: reviews abstracts for annual meeting.; RSNA. B. Alexander: Consultant; BMS, Schlesinger Associates, Abbvie, Precision Health Economics. A.A. Aizer: None.
abnormality, minimizing brain DVH without sacrificing coverage through optimization with intensity-modulated RT. TLCs were retrospectively compared between patients who were treated with standard-field vs. limited-field RT during the first 3 months after beginning RT. The Mann-Whitney U test was used to compare week 6, week 12, and nadir (lowest TLC within 3 months of RT) lymphocyte counts. ASL was defined as TLC of <500 cells/mL within 3 months of starting RT. ASL rate, Progression-free survival (PFS), and OS between two treatment periods were compared using Kaplan-Meier analysis. Results: One-hundred seventy patients were treated with standard-field RT while 60 patients were treated with limited-field RT. Age, surgery type, MGMT methylation status, and IDH mutation status were not significantly different between the two groups. Median TLCs of standard-field and limited-field RT were 1400 cells/mL vs. 1500 cells/mL at baseline before RT, 800 cells/mL vs. 900 cells/mL at week 6 (p Z 0.182), 900 cells/mL vs. 1100 cells/mL at week 12 (p Z 0.049), and 650 cells/mL vs. 800 cells/mL at nadir (p Z 0.043), respectively. Rates of ASL were 30.6% for standard-field and 18.2% for limited field (p Z 0.103). After a median follow-up of 11 months, median PFS was 8 versus 6 months (p Z 0.95) and median OS was 14 versus 15 months (p Z 0.28) between the standard-field and limitedfield RT groups. Conclusion: Limited-field RT appears to be associated with reduced TLC at week 12 and at nadir for GBM patients receiving CRT. Reduction of treatment volume does not appear to adversely affect PFS and OS. With increasing development of immunotherapy for GBM, limited-field RT may warrant further investigation prospectively. Author Disclosure: S. Rudra: None. C. Hui: None. Y.J. Rao: None. X. Chang: None. C. Tsien: Honoraria; Merck. D. Yang: Research Grant; AHRQ, Varian Medical System, ViewRay Inc.. D. Thotala: None. D.E. Hallahan: Research Grant; MGS, LLC. Stock; MGS, LLC, GenVec. ; BJH Medical Center. J.L. Campian: None. J. Huang: Honoraria; Viewray Inc.. Speaker’s Bureau; Viewray Inc.. Travel Expenses; Viewray Inc..
2247 Effect of Radiation Treatment Volume Reduction on Lymphopenia in Patients Receiving Chemoradiation for Glioblastoma Multiforme S. Rudra,1 C. Hui,2 Y.J. Rao,1 X. Chang,3 C. Tsien,4 D. Yang,5 D. Thotala,6 D.E. Hallahan,7 J.L. Campian,8 and J. Huang1; 1Washington University School of Medicine, Department of Radiation Oncology, St. Louis, MO, 2 Saint Louis University School of Medicine, St. Louis, MO, 3Washington University in St. Louis, St. Louis, MO, 4Washington University St Louis, St Louis, MO, 5Washington University School of Medicine, St. Louis, MO, 6 Washington University in St. Louis, Department of Radiation Oncology, St. Louis, MO, 7Washington University, St. Louis, MO, 8Washington University in St. Louis, Department of Medical Oncology, St. Louis, MO Purpose/Objective(s): Acute severe lymphopenia (ASL) occurs frequently in glioblastoma (GBM) patients receiving radiation therapy and concurrent temozolomide (CRT). Previous studies have demonstrated correlation between ASL and overall survival (OS) in GBM patients as well as between ASL and the brain dose-volume histogram (DVH). Our study aims to evaluate whether reduction in radiation treatment volume in GBM patients influences total lymphocyte counts (TLCs) within the first 3 months of radiation therapy (RT). Materials/Methods: A total of 230 patients with supratentorial/ nonmetastatic GBM were treated with standard-fractionated CRT from January 2007 to December 2016 and had laboratory data to evaluate TLC. Before January 2015, patients were treated with standard-field RT. After January 2015, strategies to minimize treatment volumes were implemented at our institution (limited-field RT): reduction of clinical treatment volume (CTV) margin, elimination of routine inclusion of the entire T2
2248 Gross Total Resection and Adjuvant Radiation are Most Significant Predictors of Improved Survival in Atypical Meningioma N.R. Rydzewski,1,2 M.S. Lesniak,3 J.P. Chandler,3 M.C. Tate,3 and S. Sachdev1; 1Department of Radiation Oncology, Northwestern University Robert H. Lurie Comprehensive Cancer Center, Chicago, IL, 2 Northwestern Feinberg School of Medicine, Chicago, IL, 3Department of Neurological Surgery, Northwestern University Robert H. Lurie Comprehensive Cancer Center, Chicago, IL Purpose/Objective(s): Aytpical and malignant meningiomas are far less common than benign meningiomas. As aggressive lesions, they are prone to local recurrence, recalcitrant to salvage therapies and ultimately lead to decreased survival. While adjuvant radiotherapy is commonly utilized for malignant meningiomas, there is more controversy in setting of atypical lesions. There is limited prospective data in this setting thus far. A population-based analysis was undertaken. Materials/Methods: The National Cancer Database (NCDB) was queried to investigate cases of histologically confirmed atypical (grade II) and malignant (grade III) meningiomas diagnosed from 2004 to 2014. This included 7,291 patients with atypical meningiomas and 1,655 patients with malignant meningiomas; during this same period 51,478 patients were diagnosed with benign (grade I) meningiomas. Data collected included: surgical extent (gross-total vs subtotal), radiotherapy utilization including stereotactic radiosurgery (SRS) as well as tumor size and Ki67. Adjuvant radiotherapy was defined as completion within 6 months of diagnosis. Survival analysis was performed using Kaplan-Meier estimates with the log-rank test of significance and cox univariate and multivariate regression. Logistic regression was used to determine factors associated with utilization of radiation.
International Journal of Radiation Oncology Biology Physics
Materials/Methods: We identified 149 patients with adenocarcinoma of the lung and newly diagnosed brain metastases without a targetable mutation diagnosed between 2000-2015 who received stereotactic radiation (either stereotactic radiosurgery or hypofractionated stereotactic radiotherapy) at a single institution. Cox regression was used to assess whether patients managed with stereotactic radiation for brain metastases display improved intracranial disease control and higher rates of radiation necrosis when also managed with pemetrexed as systemic therapy. Kaplan-Meier (KM) analysis was used to estimate freedom from radiographic necrosis and freedom from new brain metastases at 1 year. Results: Among the entire cohort, 105 patients received pemetrexed while 44 patients did not. No significant differences in age or performance status were noted between the cohorts. Pemetrexed use was associated with increased radiographic necrosis after stereotactic radiation (pZ0.03). Freedom from radiographic necrosis at 1 year was 75.9% (95% CI, 62.1%-85.3%) for those who received pemetrexed compared to 90.2% (95% CI, 72.3%-96.8%) among those who did not receive pemetrexed. There was a trend towards a higher incidence of radiation necrosis in patients receiving pemetrexed before versus after stereotactic radiation (pZ0.12). Among patients with newly-diagnosed adenocarcinoma of the lung who were chemotherapy-naı¨ve, use of poststereotactic radiation pemetrexed versus all other systemic regimens was associated with a trend to improved distant intracranial control (pZ0.11). At 1 year, freedom from new brain metastases among patients receiving post-stereotactic radiation pemetrexed was 39.0% (95% CI, 26.1%-51.7%) compared to18.3% (95% CI, 2.9%-44.1%) among those who received any other systemic therapy regimen after stereotactic radiation. Conclusion: Results of this retrospective study suggest that stereotactic radiation with pemetrexed administration is associated with an increased risk of radiation necrosis in the brain. Patients receiving pemetrexed may be less likely to develop new brain metastases. Author Disclosure: Z.J. Reitman: None. D.N. Cagney: None. A. Martin: None. S.E. Weiss: reviews abstracts for annual meeting.; RSNA. B. Alexander: Consultant; BMS, Schlesinger Associates, Abbvie, Precision Health Economics. A.A. Aizer: None.
abnormality, minimizing brain DVH without sacrificing coverage through optimization with intensity-modulated RT. TLCs were retrospectively compared between patients who were treated with standard-field vs. limited-field RT during the first 3 months after beginning RT. The Mann-Whitney U test was used to compare week 6, week 12, and nadir (lowest TLC within 3 months of RT) lymphocyte counts. ASL was defined as TLC of <500 cells/mL within 3 months of starting RT. ASL rate, Progression-free survival (PFS), and OS between two treatment periods were compared using Kaplan-Meier analysis. Results: One-hundred seventy patients were treated with standard-field RT while 60 patients were treated with limited-field RT. Age, surgery type, MGMT methylation status, and IDH mutation status were not significantly different between the two groups. Median TLCs of standard-field and limited-field RT were 1400 cells/mL vs. 1500 cells/mL at baseline before RT, 800 cells/mL vs. 900 cells/mL at week 6 (p Z 0.182), 900 cells/mL vs. 1100 cells/mL at week 12 (p Z 0.049), and 650 cells/mL vs. 800 cells/mL at nadir (p Z 0.043), respectively. Rates of ASL were 30.6% for standard-field and 18.2% for limited field (p Z 0.103). After a median follow-up of 11 months, median PFS was 8 versus 6 months (p Z 0.95) and median OS was 14 versus 15 months (p Z 0.28) between the standard-field and limitedfield RT groups. Conclusion: Limited-field RT appears to be associated with reduced TLC at week 12 and at nadir for GBM patients receiving CRT. Reduction of treatment volume does not appear to adversely affect PFS and OS. With increasing development of immunotherapy for GBM, limited-field RT may warrant further investigation prospectively. Author Disclosure: S. Rudra: None. C. Hui: None. Y.J. Rao: None. X. Chang: None. C. Tsien: Honoraria; Merck. D. Yang: Research Grant; AHRQ, Varian Medical System, ViewRay Inc.. D. Thotala: None. D.E. Hallahan: Research Grant; MGS, LLC. Stock; MGS, LLC, GenVec. ; BJH Medical Center. J.L. Campian: None. J. Huang: Honoraria; Viewray Inc.. Speaker’s Bureau; Viewray Inc.. Travel Expenses; Viewray Inc..
2247 Effect of Radiation Treatment Volume Reduction on Lymphopenia in Patients Receiving Chemoradiation for Glioblastoma Multiforme S. Rudra,1 C. Hui,2 Y.J. Rao,1 X. Chang,3 C. Tsien,4 D. Yang,5 D. Thotala,6 D.E. Hallahan,7 J.L. Campian,8 and J. Huang1; 1Washington University School of Medicine, Department of Radiation Oncology, St. Louis, MO, 2 Saint Louis University School of Medicine, St. Louis, MO, 3Washington University in St. Louis, St. Louis, MO, 4Washington University St Louis, St Louis, MO, 5Washington University School of Medicine, St. Louis, MO, 6 Washington University in St. Louis, Department of Radiation Oncology, St. Louis, MO, 7Washington University, St. Louis, MO, 8Washington University in St. Louis, Department of Medical Oncology, St. Louis, MO Purpose/Objective(s): Acute severe lymphopenia (ASL) occurs frequently in glioblastoma (GBM) patients receiving radiation therapy and concurrent temozolomide (CRT). Previous studies have demonstrated correlation between ASL and overall survival (OS) in GBM patients as well as between ASL and the brain dose-volume histogram (DVH). Our study aims to evaluate whether reduction in radiation treatment volume in GBM patients influences total lymphocyte counts (TLCs) within the first 3 months of radiation therapy (RT). Materials/Methods: A total of 230 patients with supratentorial/ nonmetastatic GBM were treated with standard-fractionated CRT from January 2007 to December 2016 and had laboratory data to evaluate TLC. Before January 2015, patients were treated with standard-field RT. After January 2015, strategies to minimize treatment volumes were implemented at our institution (limited-field RT): reduction of clinical treatment volume (CTV) margin, elimination of routine inclusion of the entire T2
2248 Gross Total Resection and Adjuvant Radiation are Most Significant Predictors of Improved Survival in Atypical Meningioma N.R. Rydzewski,1,2 M.S. Lesniak,3 J.P. Chandler,3 M.C. Tate,3 and S. Sachdev1; 1Department of Radiation Oncology, Northwestern University Robert H. Lurie Comprehensive Cancer Center, Chicago, IL, 2 Northwestern Feinberg School of Medicine, Chicago, IL, 3Department of Neurological Surgery, Northwestern University Robert H. Lurie Comprehensive Cancer Center, Chicago, IL Purpose/Objective(s): Aytpical and malignant meningiomas are far less common than benign meningiomas. As aggressive lesions, they are prone to local recurrence, recalcitrant to salvage therapies and ultimately lead to decreased survival. While adjuvant radiotherapy is commonly utilized for malignant meningiomas, there is more controversy in setting of atypical lesions. There is limited prospective data in this setting thus far. A population-based analysis was undertaken. Materials/Methods: The National Cancer Database (NCDB) was queried to investigate cases of histologically confirmed atypical (grade II) and malignant (grade III) meningiomas diagnosed from 2004 to 2014. This included 7,291 patients with atypical meningiomas and 1,655 patients with malignant meningiomas; during this same period 51,478 patients were diagnosed with benign (grade I) meningiomas. Data collected included: surgical extent (gross-total vs subtotal), radiotherapy utilization including stereotactic radiosurgery (SRS) as well as tumor size and Ki67. Adjuvant radiotherapy was defined as completion within 6 months of diagnosis. Survival analysis was performed using Kaplan-Meier estimates with the log-rank test of significance and cox univariate and multivariate regression. Logistic regression was used to determine factors associated with utilization of radiation.