Melanoma GPA as a novel prognostic scoring model based on initial brain metastasis velocity

Upon initial presentation, initial brain metastasis velocity (iBMV) is a prognostic factor for patients with brain metastases (BMs). Based on this metric, this study validated the predictive value of iBMV and introduced a Graded Prognostic Assessment (GPA)-derived scale known as melanoma-GPA. We conducted a retrospective cohort study and enrolled patients diagnosed with malignant melanoma brain metastases (MBMs) between December 2010 and February 2023. We performed univariate and multivariate Cox regression analyses to identify prognostic factors affecting overall survival (OS). A novel prognostic scoring model was derived using these factors, then melanoma-GPA and GPA predictive capabilities were assessed and compared. We enrolled 111 patients with a median OS and iBMV of 11.80 months and 2.27, respectively. The Kaplan-Meier curves showed that patients with iBMV ≤ 2.27 have better prognostic performance (P < 0.001). Multivariate analysis showed that iBMV (P = 0.035), Karnofsky Performance Status (P < 0.001), serum lactate dehydrogenase (P = 0.028), serum albumin (P = 0.041), and the systemic immune-inflammation index (P = 0.042) were independent predictors of OS. Subsequently, we established the melanoma-GPA. After risk stratification, the low-risk group had significantly longer survival than the high-risk group (17.7 vs. 7.9 months). In addition, over 3 years, the melanoma-GPA area under the curve (AUC) values were superior to GPA AUC values, indicating that melanoma-GPA has greater predictive accuracy. This study has shown that iBMV is a prognostic indicator in MBMs. Based on this factor, we established the Melanoma-GPA to comprehensively and objectively assess the prognosis of MBMs.