Salvage treatment of distant recurrent brain metastases with Gamma Knife surgery

The aim of the study was to analyze the results following salvage Gamma KnifeA (R) surgery (GKS) for distant recurrent brain metastases in patients previously treated with GKS for brain metastases. Survival time and freedom from new distant recurrences (DR) were studied in 251 patients treated with salvage GKS for brain metastases that had developed following a first GKS. The patients were followed prospectively and the results related to a number of patient parameters as well as the results following the first GKS. The median survival time was 9.6 months, and the median time of freedom from developing DR was 7.5 months after salvage GKS. The survival time was unrelated to age, gender, prior WBRT, and primary disease. It was significantly longer in patients with a single DR at salvage GKS as compared to those with multiple ones (16 versus 8.3 months). Patients with 2-4 DRs lived longer than those with > 4 lesions, 10 versus 5.8 months. The survival was significantly longer following salvage GKS as compared to following the first GKS. The prognosis of a patient with DR may therefore be less ominous than previously assumed. A classification system for DRs based on their clinical impact and treatability is therefore suggested. The longer survival time following salvage GKS as compared to following the first GKS suggests that many patients benefit from salvage GKS. A classification system of DR is suggested to estimate its clinical impact.