A retrospective study of GKRS-treated MET patients: Tumor numbers of two-four versus five or more

Masaaki Yamamoto1, Takuya Kawabe2, Bierta E. Barfod3, Yoichi Urakawa3

1Ibaraki, Japan 2Hitachi-Naka, Japan 3Katsuta Hospital Mito GammaHouse

Keywords: brain metastasis, outcome, gamma knife, radiosurgery, lung cancer

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     The role of stereotactic radiosurgery for brain MET patients with tumor numbers (TNs) of five or more is not fully understood.
     We worked to determine outcomes in patients with higher numbers of metastases.
     Among our consecutive series of 2502 patients with brain METs, who underwent GKRS during the 1998-2011 period, 1775 (740 females, 1035 males, mean age; 65 range; 19-92 years) with TNs of two or more (median; 5, maximum; 89) were chosen for this retrospective study.
      Original tumor most-commonly stemmed from the lung (1183 patients, 66.6%), followed by breast (214, 12.1%), lower alimentary tract (109, 6.1%), upper alimentary tract (67, 3.6%), kidney (60, 3.9%), other organs (110, 6.2%) and unknown (34, 2.0%). Among the 1775 patients, 796 had TNs of two-four (group-A) and the other 975 of five or more (group-B).
     Median survival time (MST) after GKRS was significantly longer in group-A (7.4 months) than in group-B (5.9, p<.0001). However, there were no significant MST differences between the two groups based on RPA class I (22.2 vs. 16.6, p=.0671), II-a (18.6 vs. 18.3, p=.3045) and II-b (9.3 vs. 9.7, p=.9113). The cause of death was non-brain diseases in 88.0% of group-A and 88.8% of group-B patients (p=.7186). A second GKRS was required for newly-diagnosed lesions in 31.9% of group-A and 25.6% of group-B patients (p=0036).
     This was a retrospective analysis of a large patient sample.
     We conclude that patients with RPA class I, II-a and II-b are good candidates for GKRS even if TNs exceed five.
     This study provides further evidence of the role of radiosurgery for larger numbers of tumors.


Project Roles:

M. Yamamoto (), T. Kawabe (), B. Barfod (), Y. Urakawa ()