What Factors Predict The Response Of Larger Brain Metastases To Radiosurgery?

Huai-che Yang1, Hideyuki Kano, MD, PhD2, L Dade Lunsford1, Ajay Niranjan, MCh2, John C. Flickinger, MD3, Douglas Kondziolka, MSc, MD2

1UPMC, Pittsburgh, USA 2Department of Neurological Surgery, University of Pittsburgh 3Department of Radiation Oncology, University of Pittsburgh

Keywords: brain metastasis, radiosurgery, gamma knife, brain tumor, outcome

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     Stereotactic radiosurgery (SRS) is an important management option for patients with brain metastases.
     To assess the potential role of SRS for larger metastatic brain tumors, we reviewed our recent experience
     Between 2004 and 2008, 70 patients with a metastatic brain tumor larger than 3 cm in maximum diameter underwent Gamma knife® SRS.
     Patients underwent Gamma knife® SRS, thirty-three patients had received previous whole brain radiation therapy (WBRT) and 37 received only SRS.
     At a median first imaging follow-up of 2 months (range, 0.7-4.7 months) after radiosurgery, 29 (41%) tumors had more than a 50% volume reduction, 22 (31%) tumors had 10-50% volume reduction, 13 (19%) tumors were stable and six (9%) tumors were larger. We also evaluated  brain edema  using MRI T2 images In 11 patients (16%), the peritumoral edema volume was reduced by more than 50%, in 25 (36%) was reduced by 10-50%, in 21 (30%) was stable and in 13 (19%) was increased. Twenty (36%) discontinued corticosteroids by the time of first imaging follow-up. Because of persistent symptoms, seven patients (10%) required a craniotomy to remove the tumor. In univariate analysis, a better tumor volume reduction (>50%) was associated with a single metastasis (p=0.012), no previous WBRT (p=0.002), and a tumor volume < 16cc (p=0.002). The better peritumoral edema volume reduction (>50%) was associated with a single metastasis (p=0.024), no previous WBRT (p=0.05), and breast cancer histology (p=0.044).
     This is a retrospective study.
     Larger metastatic brain tumors responded favorably to SRS.
     Tumor volume and edema responded better in patients who underwent SRS alone.


Project Roles:

H. Yang (), H. Kano (), L. Lunsford (), A. Niranjan (), J. Flickinger (), D. Kondziolka ()