First follow‐up radiographic response is one of the predictors of local tumor progression and radiation necrosis after stereotactic radiosurgery for brain metastases

摘要

Local progression (LP) and radiation necrosis (RN) occur in >20% of cases following stereotactic radiosurgery (SRS) for brain metastases (BM). Expected outcomes following SRS for BM include tumor control/shrinkage, local progression and radiation necrosis. 1427 patients with 4283 BM lesions were treated using SRS at Cleveland Clinic from 2000 to 2012. Clinical, imaging and radiosurgery data were collected from the database. Local tumor progression and RN were the primary end points and correlated with patient and tumor‐related variables. 5.7% of lesions developed radiographic RN and 3.6% showed local progression at 6 months. Absence of new extracranial metastasis (P < 0.001), response to SRS at first follow‐up scan (local progression versus stable size (P < 0.001), partial resolution versus complete resolution at first follow up [P = 0.009]), prior SRS to the same lesion (P < 0.001), IDL% (≤55; P < 0.001), maximum tumor diameter (>0.9 cm; P < 0.001) and MD/PD gradient index (≤1.8, P < 0.001) were independent predictors of high risk of local tumor progression. Absence of systemic metastases (P = 0.029), good neurological function at 1st follow‐up (P ≤ 0.001), no prior SRS to other lesion (P = 0.024), low conformity index (≤1.9) (P = 0.009), large maximum target diameter (>0.9 cm) (P = 0.003) and response to style="fixed-case">SRS (tumor progression vs. stable size following style="fixed-case">SRS [P < 0.001]) were independent predictors of high risk of radiographic style="fixed-case">RN. Complete tumor response at first follow‐up, maximum tumor diameter <0.9 cm, tumor volume <2.4 cc and no prior style="fixed-case">SRS to the index lesion are good prognostic factors with reduced risk of style="fixed-case">LP following style="fixed-case">SRS. Complete tumor response to style="fixed-case">SRS, poor neurological function at first follow‐up, prior style="fixed-case">SRS to other lesions and high conformity index are favorable factors for not developing style="fixed-case">RN. Stable or partial response at first follow‐up after style="fixed-case">SRS have same impact on local progression and style="fixed-case">RN compared to those with complete resolution or progression.