ESTRO 2020 Abstract Book

S465 ESTRO 2020

Cancer Center in May 2008 ‒ April 2018 . For the initial treatment to BM, 64 patients received upfront stereotactic radiosurgery (SRS); 21 patients received whole brain radiotherapy (WBRT), and 3 patients received surgery. Endpoints were brain metastasis progression free survival (BMPFS) from the initiation of BM treatment, times to local and distant failure from the start of BM treatment, and overall survival (OS) from BM diagnosis. Both intracranial- local and -distant failure are considered as BM progression. Local failures is defined as increased in size of any treated lesions per radiology report or assessment of treating physicians. Kaplan-Meier analysis and Cox proportional hazard regression models were used to estimate survival curves and identify prognostic factors. Results The median interval between the diagnoses of primary breast cancer and BM was 24.6 months (mo) (95% confidence interval 9.4 ‒ 110.7). The median OS time for all patients was 13.3 months, and the cumulative survival rates were 54.6% at 1 year and 29.8% at 2 years. Factors independently associated with increased risk of death in multivariate analysis were Karnofsky performance score (KPS) <70 (p=0.003) and uncontrolled extracranial metastasis at BM diagnosis (p=0.03). No significant difference was found for OS between patients initially treated with SRS or WBRT ( p =0.389). The median BMPFS time was 6.9 months (95% confidence interval 4.5 ‒ 8.9). Eight out of 53 patients (15.1%) treated with upfront SRS and 10 out of 21 patients (47.6%) treated with upfront WBRT experienced local failure. Univariate analysis showed that patients who received upfront SRS or had a single BM at diagnosis had longer time to local failure than those who received upfront WBRT ( p =0.004) or multiple BMs ( p =0.02), but no significant differences were found in multivariate analysis. Twenty-eight out of 53 patients (52.8%) treated with upfront SRS, and 11 out of 21 patients (52.4%) treated with upfront WBRT experienced distant brain failure. There is no significant difference in the time to distant failure between upfront SRS and upfront WBRT. Conclusion Patients with BM from TNBC have median OS of 13.3 mo and BMPFS of 6.9 mo. Good KPS and controlled extracranial diseases were independent prognostic factors for better OS. Initial SRS and single BM at diagnosis were associated with longer time to local failure and this may be related to patient selection. Prospective studies of larger numbers of patients with TNBC and different treatments for BMs are needed. PO-0866 The relation between post-radiation injury and postoperative ischemia in diffuse glioma treatment A.T.J. Van Der Boog 1 , J.J.C. Verhoeff 1 , J.W. Dankbaar 2 , T.J. Snijders 3 , P.A.J. Robe 3 1 University Medical Center Utrecht, Radiation Oncology, Utrecht, The Netherlands ; 2 University Medical Center Utrecht, Radiology, Utrecht, The Netherlands ; 3 University Medical Center Utrecht, Neurology & Neurosurgery, Utrecht, The Netherlands Purpose or Objective Cerebral gliomas are often treated with surgery and subsequent (chemo-)radiotherapy. However, postoperative ischemia and post-radiation brain injury, including pseudoprogression and radionecrosis, are frequent complications after intensive treatment (figure 1), occurring in approximately 60% and 20% of the patients, respectively. The injuries can be symptomatic, leading to increased intracranial pressure and/or neurological deficits, and impact the patient’s quality of life. Since both types of lesions appear to have a vascular origin, we

Purpose or Objective Several studies have shown that the SRS alone can improve the control of the treated lesions and improve quality of life in patients with up to 10 brain metastases. However, treatment of patients with metastatic disease and unfavorable risk factors is still controversial and not well studied. We analyzed brain metastases patients with unfavorable risk factors to optimize qulification to SRS alone. Material and Methods Data prospectively collected and introduced into a registry of patients treated with SRS in our department were analyzed. At least one unfavorable prognostic factor were defined for 85 patients treated with SRS only for brain metastases between 04.2018-03.2019. The unfavorable clinical factors were defined according to extracerebral disease, molecular results, age, line of systemic therapy, mass effect and neurological symptoms. Sum of factors was 1- when one factor was favorable, was 6 - when all six factors were favorable (such patient was excluded form analysis). Additionaly Zubrod performance scale, number of brain metastases, intracranial disease volume, dose, fractions,histopathology, GPA score and systemic treatment were analyzed. Univariate analyses were performed. Survival analysis was performed based on Kaplan-Meier curves. The logistic regression (stepwise forward logistic regression) is performed to find variables which are the most important in predicting 3-month survival. ROC analysis was used to find the optimal cut-off point for the GPA scale, the sum of specific clinical characteristics and the Zubrod scale.The survival function percentiles and the probability of 3-month survival were calculated.The 2 survival curves were compared using the log-rank test and Gehan's Wilcoxon test. Results Median survival of the total cohort of patients was 6 months. Patients with severe neurological symptoms presented worse survival. Among unfavorable risk factors more then 3 tumors of at least 3 cm concomitant with neurological deterioration or Zubrod 3 concomitant with neurological deterioration correlates with poor outcome, also GPA score of less then 2 was related to risk of early death in logistic regression (p<0,03) . Death within 3 months was predicted by sum of factors lower then 4 (AUC=0,684), GPA less then 2 (AUC=0,687) and Zubrod 3 (AUC=0,737) . Conclusion SRS alone is an effective treatment even in patients with unfavorable risk factors. However, severe neurological deterioration concomitant with Zubrod 3 or extensive extracranial disease are connected with high risk of death within 3 months. More specifically, the sum of at least 4 of analyzed factors may justified qualification to SRS. PO-0865 Survival outcomes and prognosis in patients with triple-negative breast cancer and brain metastases R. An 1 , Y. Wang 1 , C. Gao 2 , A.S. Raghavendra 2 , D. Amaya 1 , N. Ibrahim 2 , J. Li 1 1 MD Anderson Cancer Center- University of Texas, Radiation Oncology, Houston, USA ; 2 MD Anderson Cancer Center- University of Texas, Breast Medical Oncology, Houston, USA Purpose or Objective Triple-negative breast cancer (TNBC) has a high propensity for brain metastasis (BM) and a poor prognosis. We evaluated survival outcomes and prognostic factors among patients with TNBC and BMs. Material and Methods We retrospectively reviewed 88 patients with BM from historically confirmed TNBC treated at MD Anderson

suspect a correlation. Material and Methods

This study investigated the relation between postoperative ischemia, defined as diffusion restriction on early postoperative diffusion-weighted imaging (DWI), and post-