Validation of a survival score for patients treated with whole-brain radiotherapy for brain metastases

Background: This study was performed to validate a scoring system published in 2008 to predict the survival of patients receiving whole-brain radiotherapy (WBRT) alone for brain metastases. Methods: The scoring system included four independent prognostic factors: age, performance status, extracranial metastases, and interval between first diagnosis of cancer and WBRT. The score for each prognostic factor was determined by dividing the 6-month survival rate (in %) by 10. The total score represented the sum of the scores for each prognostic factor. Total scores ranged from 9-18 points, and patients were divided into four groups. In the present study, 350 new patients were evaluated in order to validate the previously developed score. Results: In the present validation study, the 6-month survival rates were 8 % for patients with a score of 9-10 points (group A), 24 % for those with a score of 11-13 points (group B), 51 % for those with a score of 14-16 points (group C), and 82 % for those with scores of 17-18 points (group D), respectively (p < 0.001). In our previous study published in 2008, the 6-month survival rates were 6 %, 15 %, 43 %, and 76 %, respectively (p < 0.001). The comparisons between each of the four prognostic groups of both series did not reveal a significant difference. Conclusion: In this study, the 6-month survival rates of the four prognostic groups were not significantly different from those of the preceding study. This demonstrates the validity and reproducibility of this score. The score can help select the appropriate treatment for the individual patient and help design prospective trials.