Top Line: What are the outcomes for preoperative SRS for resectable brain metastases?
The Study: Radiation significantly reduces the risk of local recurrence after brain metastasis resection. However, resection cavities are often irregular, target volumes include more normal brain, and there is a potential risk of leptomeningeal seeding following resection. This has led to increasing use of preoperative SRS at some centers. INTERNEO was an international cohort of 179 patients who received preop SRS for 189 brain metastases. Median tumor size was 2.9cm, and just over half of lesions were treated with single fraction SRS (53%). The most common single fraction dose was 18 Gy, and the most common multi-fraction doses were 24 Gy (55%) and 27 Gy (25%). At 12 months, the rate of local recurrence was just 4.6%, the rate of grade 2+ radiation necrosis was 1.8%, and the rate of nodular leptomeningeal disease was 1.2%. These outcomes compare favorably to the rates of local recurrence at 1 year with postop SRS (19.6%) or WBRT (12.9%) in the NCCTG N107C/CEC.3 trial. The favorable local control in this study may have been related to the use of relatively higher preop doses, particularly with single fraction SRS. In another recent large cohort study of preop SRS where the median single-fraction dose was 15 Gy, local recurrence at 1 year was 11.9%. In that study, a higher BED 3-fraction dose was associated with better local control.
TBL: In this cohort of patients treated with preop SRS, local control was >95% at 1 year and the rate of grade 2+ radiation necrosis was 1.8%. | Udovicich, Int J Radiat Oncol Biol Phys 2024
The Study: Radiation significantly reduces the risk of local recurrence after brain metastasis resection. However, resection cavities are often irregular, target volumes include more normal brain, and there is a potential risk of leptomeningeal seeding following resection. This has led to increasing use of preoperative SRS at some centers. INTERNEO was an international cohort of 179 patients who received preop SRS for 189 brain metastases. Median tumor size was 2.9cm, and just over half of lesions were treated with single fraction SRS (53%). The most common single fraction dose was 18 Gy, and the most common multi-fraction doses were 24 Gy (55%) and 27 Gy (25%). At 12 months, the rate of local recurrence was just 4.6%, the rate of grade 2+ radiation necrosis was 1.8%, and the rate of nodular leptomeningeal disease was 1.2%. These outcomes compare favorably to the rates of local recurrence at 1 year with postop SRS (19.6%) or WBRT (12.9%) in the NCCTG N107C/CEC.3 trial. The favorable local control in this study may have been related to the use of relatively higher preop doses, particularly with single fraction SRS. In another recent large cohort study of preop SRS where the median single-fraction dose was 15 Gy, local recurrence at 1 year was 11.9%. In that study, a higher BED 3-fraction dose was associated with better local control.
TBL: In this cohort of patients treated with preop SRS, local control was >95% at 1 year and the rate of grade 2+ radiation necrosis was 1.8%. | Udovicich, Int J Radiat Oncol Biol Phys 2024