Validation of the new graded prognostic assessment scale for brain metastases: a multicenter prospective study

Salvador Villà,Josep Jové,Christophe Combescure,Carme Balañà,Paloma Puyalto,Damien C Weber,Cristina Moretones,Francesc Graus,Patricia Cuadras,Anabel Mañes,Jordi Bruna,Eugènia Verger

doi:10.1186/1748-717x-6-23

Abstract

BackgroundPrognostic indexes are useful to guide tailored treatment strategies for cancer patients with brain metastasis (BM). We evaluated the new Graded Prognostic Assessment (GPA) scale in a prospective validation study to compare it with two published prognostic indexes.MethodsA total of 285 newly diagnosed BM (n = 85 with synchronous BM) patients, accrued prospectively between 2000 and 2009, were included in this analysis. Mean age was 62 ± 12.0 years. The median KPS and number of BM was 70 (range, 20-100) and 3 (range, 1-50), respectively. The majority of primary tumours were lung (53%), or breast (17%) cancers. Treatment was administered to 255 (89.5%) patients. Only a minority of patients could be classified prospectively in a favourable prognostic class: GPA 3.5-4: 3.9%; recursive partitioning analysis (RPA) 1, 8.4% and Basic Score for BM (BSBM) 3, 9.1%. Mean follow-up (FU) time was 5.2 ± 4.7 months.ResultsDuring the period of FU, 225 (78.9%) patients died. The 6 months- and 1 year-OS was 36.9% and 17.6%, respectively. On multivariate analysis, performance status (P < 0.001), BSBM (P < 0.001), Center (P = 0.007), RPA (P = 0.02) and GPA (P = 0.03) were statistically significant for OS. The survival prediction performances' of all indexes were identical. Noteworthy, the significant OS difference observed within 3 months of diagnosis between the BSBM, RPA and GPA classes/groups was not observed after this cut-off time point. Harrell's concordance indexes C were 0.58, 0.61 and 0.58 for the GPA, BSBM and RPA, respectively.ConclusionsOur data suggest that the new GPA index is a valid prognostic index. In this prospective study, the prediction performance was as good as the BSBM or RPA systems. These published indexes may however have limited long term prognostication capability.

Highlights

Prognostic indexes are useful to guide tailored treatment strategies for cancer patients with brain metastasis (BM)
Their definition yielded class IIIa defined as age < 65 years, controlled primary tumour and single BM, class IIIc defined as age > 65 years, uncontrolled primary tumour and multiple BM, and class IIIb for all other cases
Factors significantly associated with improved survival were the performance status, center and the three prognostic indexes (Table 5)

Summary

Introduction

Prognostic indexes are useful to guide tailored treatment strategies for cancer patients with brain metastasis (BM). The same authors validated this RPA classification 3 years later using results from RTOG 91-04 trial (a randomized study comparing two dose-fractionation schemes) matching with the RPA dataset [6]. This prognostic system was subsequently validated by other authors [7,8,9]. Based on multivariate analysis of 916 patients, Lutterbach et al suggested the addition of the classification by dividing class III into 3 separate groups was prognostically relevant [4] Their definition yielded class IIIa defined as age < 65 years, controlled primary tumour and single BM, class IIIc defined as age > 65 years, uncontrolled primary tumour and multiple BM, and class IIIb for all other cases

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