The First Survival Score for Patients Treated with Whole-Brain Radiotherapy Plus Simultaneous Integrated Boost for Brain Metastases

SIMPLE SUMMARY: A model was generated to judge survival after whole-brain radiotherapy plus simultaneous boost (WBRT+SIB) for cerebral metastases. Initially, three models, each including three prognostic groups, were created and compared for accuracy in prognosticating death ≤ 6 and survival ≥ 6 months using the corresponding positive predictive values (PPVs). PPVs to predict death ≤ 6 and survival ≥ 6 months were 85% and 57% for Model 1 (considering performance status = KPS and the number of lesions), 83% and 75% for Model 2 (KPS, lesions, age), and 86% and 78% for Model 3 (KPS, lesions, age, extra-cerebral metastases), respectively. The three models were accurate in predicting death ≤ 6 months and Models 2 and 3 were more precise than Model 1 in predicting survival ≥6 months. Model 2 appears preferable for many patients. Patients with poor survival prognoses may not benefit from adding SIB. ABSTRACT: A modern approach for brain metastases includes whole-brain radiotherapy plus simultaneous boost (WBRT+SIB). We developed a survival score in 128 patients treated with WBRT+SIB. Three models, each including three prognostic groups, were created. Positive predictive values (PPVs) for death ≤6 and survival ≥6 months were calculated. On multivariate analyses, performance score (KPS) and the number of brain metastases were significantly associated with survival. On univariate analyses, age showed a strong trend, and extra-cerebral cranial metastases a trend. In Model 1 (KPS, number of lesions), compared groups had 6-month survival rates of 15%, 38% and 57%. In Model 2 (KPS, lesions, age), rates were 17%, 33% and 75%, and in Model 3 (KPS, lesions, age, extra-cerebral metastases), 14%, 34% and 78%. PPVs for death ≤6 and survival ≥6 months were 85% and 57% (Model 1), 83% and 75% (Model 2), and 86% and 78% (Model 3). Thus, all models were accurate in predicting death ≤ 6 months; poor-prognosis patients may not benefit from SIB. Models 2 and 3 were superior in predicting survival ≥ 6 months. Given that Model 3 requires more data (including extensive staging), Model 2 is considered favorable for many patients. If extra-cerebral metastases are already known or extensive staging has been performed, Model 3 can also be used.