title: How many metastases can be treated with radiosurgery?
abstract: We describe postradiosurgical treatment outcomes of our consecutive series of 1,676 patients (654 females and 1,022 males, mean age 63 years, range 19-92 years) who underwent Gamma Knife radiosurgery (GKRS) for brain metastases, focusing particularly on GKRS for multiple lesions. The most common primary cancer was lung (1,057; 63.1%), followed by alimentary tract (198; 11.8%), breast (180; 10.7%), uro-genital (113; 6.7%) and others (128; 7.6%). Mean and median lesion numbers were 7 and 3, respectively, range 1-85. The overall median survival times were 9.0 months in females and 5.9 in males after GKRS (p < 0.0001). The Kaplan-Meier method was used to assess tumor numbers by group: 1-4, 5-9, 10-14, 15-19, 20-24, 25-29, 30-39 and ≥40. The post-GKRS median survival times were 8.3, 5.3, 6.9, 5.2, 5.6, 3.0, 5.3 and 4.3 months, respectively (p < 0.0001). Also, the Kaplan-Meier method was used to compare 15 pairs of groups based on tumor numbers: 1 vs. ≥2, ≤2 vs. ≥3, ≤3 vs. ≥4, ---, and ≤15 vs. ≥16. In each of the 15 pairs, the median survival times of patients with lower tumor numbers were significantly longer than those of patients with higher tumor numbers (p < 0.0001). Furthermore, 14 other pairs of groups, based on tumor numbers, were also assessed by this method: 1 vs. 2, 2 vs. 3, 3 vs. 4, ---, and 14 vs. 15. Among the 14 pairs, only the 1 vs. 2 pair showed a significant median survival time difference (p = 0.0002); no significant differences were detected for the other 13 pairs. Although tumor number was demonstrated to have a significant impact on the duration of survival, approximately 85% of patients with brain metastasis died of causes other than brain disease progression, regardless of tumor number.
authors.affiliation: Katsuta Hospital Mito Gamma House, Ibaraki, Japan. BCD06275@nifty.com
authors.forename: Masaaki
authors.initials: M
authors.lastname: Yamamoto
authors.forename: Takuya
authors.initials: T
authors.lastname: Kawabe
authors.forename: Bierta E
authors.initials: BE
authors.lastname: Barfod
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001932:Brain Neoplasms / Q000556:secondary* / Q000601:surgery*; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011829:Radiation Dosage; D016634:Radiosurgery / Q000379:methods*; D016019:Survival Analysis; D055815:Young Adult