External Validation of the Graded Prognostic Assessment in Patients with Brain Metastases from Small Cell Lung Cancer

Background: Recently, graded prognostic assessment (GPA) for small cell lung cancer (SCLC) patients with brain metastases has been developed. This includes age, performance status, number of brain metastases and presence of extracranial metastases. The aim of the present study was to validate this four-tiered prognostic score in a European cohort of patients. Methods: The retrospective validation study included 180 patients from two centers in Germany and Norway. Results: Median survival from radiological diagnosis of brain metastases was 7 months. The GPA point sum as continuous variable (0–4 points) was significantly associated with survival (p < 0.001). However, no significant survival difference was observed between patients in the two strata with better survival (3.5–4 and 2.5–3 points, respectively). Long-term survival in the poor prognosis group (0–1 points) was better than expected. Conclusion: This study supports the prognostic impact of all four parameters contributing to the GPA. The original way of grouping the parameters and breaking the final strata did not give optimal results in this cohort. Therefore, additional validation databases from different countries should be created and evaluated.