M. Azoulay

A Phase I/II Trial of 5 Fraction Stereotactic Radiosurgery With 5-mm Margins With Concurrent and Adjuvant Temozolomide in Newly Diagnosed Supratentorial Glioblastoma Multiforme.

The spine cases included a fifth lumbar spine (case 1), fifth thoracic spine (case 2), and 10th thoracic spine metastases (case 3). Targets and organs at risk (OAR) were contoured by one experienced radiation oncologist according to International Spine Radiosurgery Consortium Consensus Guidelines and a 2 mm planning target volume (PTV) applied. The DICOM files were sent to each institute for planning. The treatment planning guidelines in the previous study included, prescribed dose of 24 Gy in two fractions with more than 70% prescribed dose to encompass D95, D0.035 <140% of the prescribed dose, and a maximum dose to the spinal cord planning organ at risk volume (PRV) or thecal sac <17 Gy. New guidelines added (D95 should be as high as possible (AHAP), D50 should be between 110% and 115% of prescribed dose and AHAP and D0.035 should be between 125% and 135% of the prescribed dose). The dose volume histograms (DVHs) were centrally reviewed. Results: In our previous study the PTV D95 ranged from 70.0% to 99.6% in case 1 (mean SD; 21.21 2.43 Gy), 70.4% to 98.8% in case 2 (20.32 2.22 Gy), and 70.0% to 94.2% in case 3 (19.78 1.97 Gy), respectively, and D50 for PTV ranged from 99.2% to 116.3% in case 1 (25.62 1.34 Gy), 91.7% to 119.6% in case 2 (25.97 2.18 Gy) and 84.2% to 114.2% in case 3 (25.57 2.14 Gy), respectively. In this study PTV D95 ranged from 80.4% to 100.0% in case 1 (21.96 1.67 Gy), 76.3% to 95.8% in case 2 (20.91 1.67 Gy), and 70.4% to 94.2% in case 3 (20.3 1.86 Gy), respectively and D50 for PTV ranged from 109.6% to 115.4% in case 1 (27.02 0.53 Gy), 110.0% to 117.5% in case 2 (27.06 0.63 Gy) and 107.5% to 115.0% in case 3 (26.89 0.67 Gy), respectively. Conclusion: We succeeded to minimize the inter-institutional variations. This study highlights dose constraints of D95, D50, and D0.035 should be used to minimize the variations. Author Disclosure: H. Tanaka: None. T. Furuya: None. Y. Kumazaki: None. M. Nakayama: None. H. Nishimura: None. M.E. Ruschin: None. D. Pinnaduwage: None. J. Phua: None. I. Thibault: None. J. StHilaire: None. L. Ma: None. A. Sahgal: None. N. Shikama: None. K. Karasawa: None.

Stereotactic radiosurgery and hypofractionated radiotherapy for glioblastoma

Glioblastoma is the most common primary brain tumor in adults. Standard therapy depends on patient age and performance status but principally involves surgical resection followed by a 6-wk course of radiation therapy given concurrently with temozolomide chemotherapy. Despite such treatment, prognosis remains poor, with a median survival of 16 mo. Challenges in achieving local control, maintaining quality of life, and limiting toxicity plague treatment strategies for this disease. Radiotherapy dose intensification through hypofractionation and stereotactic radiosurgery is a promising strategy that has been explored to meet these challenges. We review the use of hypofractionated radiotherapy and stereotactic radiosurgery for patients with newly diagnosed and recurrent glioblastoma.

The Role of Stereotactic Radiosurgery in the Reirradiation of Metastatic Spinal Tumors

The spine cases included a fifth lumbar spine (case 1), fifth thoracic spine (case 2), and 10th thoracic spine metastases (case 3). Targets and organs at risk (OAR) were contoured by one experienced radiation oncologist according to International Spine Radiosurgery Consortium Consensus Guidelines and a 2 mm planning target volume (PTV) applied. The DICOM files were sent to each institute for planning. The treatment planning guidelines in the previous study included, prescribed dose of 24 Gy in two fractions with more than 70% prescribed dose to encompass D95, D0.035 <140% of the prescribed dose, and a maximum dose to the spinal cord planning organ at risk volume (PRV) or thecal sac <17 Gy. New guidelines added (D95 should be as high as possible (AHAP), D50 should be between 110% and 115% of prescribed dose and AHAP and D0.035 should be between 125% and 135% of the prescribed dose). The dose volume histograms (DVHs) were centrally reviewed. Results: In our previous study the PTV D95 ranged from 70.0% to 99.6% in case 1 (mean SD; 21.21 2.43 Gy), 70.4% to 98.8% in case 2 (20.32 2.22 Gy), and 70.0% to 94.2% in case 3 (19.78 1.97 Gy), respectively, and D50 for PTV ranged from 99.2% to 116.3% in case 1 (25.62 1.34 Gy), 91.7% to 119.6% in case 2 (25.97 2.18 Gy) and 84.2% to 114.2% in case 3 (25.57 2.14 Gy), respectively. In this study PTV D95 ranged from 80.4% to 100.0% in case 1 (21.96 1.67 Gy), 76.3% to 95.8% in case 2 (20.91 1.67 Gy), and 70.4% to 94.2% in case 3 (20.3 1.86 Gy), respectively and D50 for PTV ranged from 109.6% to 115.4% in case 1 (27.02 0.53 Gy), 110.0% to 117.5% in case 2 (27.06 0.63 Gy) and 107.5% to 115.0% in case 3 (26.89 0.67 Gy), respectively. Conclusion: We succeeded to minimize the inter-institutional variations. This study highlights dose constraints of D95, D50, and D0.035 should be used to minimize the variations. Author Disclosure: H. Tanaka: None. T. Furuya: None. Y. Kumazaki: None. M. Nakayama: None. H. Nishimura: None. M.E. Ruschin: None. D. Pinnaduwage: None. J. Phua: None. I. Thibault: None. J. StHilaire: None. L. Ma: None. A. Sahgal: None. N. Shikama: None. K. Karasawa: None.