Scoring systems predictive of survival and local control of patients irradiated for brain metastases

Abstract

2075 Background: This study was performed to create and validate scoring systems to estimate survival and intracerebral local control at 6 months of patients irradiated for brain metastases. Methods: Data of 1,797 patients irradiated for brain metastases (1,346 whole-brain radiotherapy [WBRT], 131 radiosurgery [RS], 61 WBRT + RS, 259 resection + WBRT) were retrospectively analyzed. Patients were randomly assigned to the test group (N = 1,198) or the validation group (N = 599). In the test group, multivariate analyses (MVA, Cox proportional hazards model) were performed for survival (OS) and local control (LC). Based on the MVA results, two scoring systems were developed, one for OS and another for LC. The scores included the prognostic factors found significant on MVA. Age, performance status, extracranial metastases, interval from tumor diagnosis to RT, and number of brain metastases were significant for OS. Tumor type, performance status, interval from tumor diagnosis to RT, and number of brain metastases were significant for LC. The score for each factor was determined by dividing the 6-month OS or LC rate (%) by 10. The total score represented the sum of the scores for each factor. For OS, total scores ranged from 15–30 points, and patients were divided into three groups (15–19, 20–25, and 26–30 points). For LC, total scores ranged from 14–27 points, and patients were divided into three groups (14–18, 19–23, and 24–27 points). Results: In the test group, the 6-month OS rates were 9 ± 1% for patients with scores of 15–19 points, 41 ± 2% for those with 20–25 points, and 78 ± 2% for those with 26–30 points (p < 0.0001). The corresponding OS rates in the validation group were 7 ± 2%, 39 ± 3%, and 79 ± 3%, respectively (p < 0.0001).In the test group, the 6-month LC rates were 17 ± 3% for patients with 14–18 points, 49 ± 3% for those with 19–23 points, and 77 ± 2% for those with 24–27 points (p < 0.0001). The corresponding LC rates in the validation group were 19 ± 4%, 52 ± 4%, and 77 ± 3%, respectively (p < 0.0001). Conclusions: Patients irradiated for brain metastases can be grouped with these scores to estimate OS and LC. The OS and LC rates of the validation group were almost identical to the test group, which demonstrates the high validity and reproducibility of both scores. No significant financial relationships to disclose.