title: A prospective pilot study of two-session Gamma Knife surgery for large metastatic brain tumors.
abstract: The purpose of this prospective study is to evaluate the efficacy and limitations of two-session Gamma Knife radiosurgery (GKS) alone for large metastatic brain tumors. Inclusion criteria were as follows: (i) patients with large metastatic brain tumors (volume >15 cm(3) in the supratentorial region or >10 cm(3) in the infratentorial region), and (ii) tumors not causing clinical signs of impending cerebral herniation. Twenty-eight lesions in 27 consecutive patients (18 men and 9 women, age range 32 to 88 years, median age 65 years) were included in this study. The radiosurgical protocol was as follows: 20-30 Gy given in two fractions 3-4 weeks apart. The local tumor control rate and the overall survival rate were calculated by using the Kaplan-Meier method. Median tumor volumes were 17.8 cm(3) at first GKS and 9.7 cm(3) at second GKS. Median follow-up time was 8.9 months. The local control rate was 85 % at 6 months and 61 % at 12 months. The overall survival rate after GKS was 63 % at 6 months and 45 % at 12 months. The 1-year rate of prevention of neurological death was maintained at 78 %. Mean Karnofsky performance status (KPS) improved from 61 [95 % confidence interval (CI), 57-71] at first GKS to 80 (95 % CI, 74-85) at second GKS; the best follow-up mean KPS was 85 (95 % CI, 78-91) (p < 0.001). Local tumor recurrence necessitated craniotomy in two patients and repeat GKS in three patients. Seventeen patients died, and the causes of death were as follows: 3 from local progression, 2 from meningeal carcinomatosis, and 12 from progression of the primary tumor. Delayed symptomatic perilesional edema developed in one patient and eventually resolved with conservative treatment. Two-session GKS for large brain metastases appears to be an effective treatment in terms of both local tumor control and neurological palliation with minimal treatment-related morbidity. These data suggest that two-session GKS could be used as an alternative to surgical resection of large tumors in patients with significant comorbidity and/or at an advanced age. The optimum regimen for dose and fraction schedule remains to be established.
authors.affiliation: Saitama Gamma Knife Center, San-ai Hospital, 4-35-17 Tajima Sakura-ku, Saitama, 338-0837, Japan. yomoshoji@gmail.com
authors.forename: Shoji
authors.initials: S
authors.lastname: Yomo
authors.forename: Motohiro
authors.initials: M
authors.lastname: Hayashi
authors.forename: Claire
authors.initials: C
authors.lastname: Nicholson
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001932:Brain Neoplasms / Q000401:mortality / Q000556:secondary* / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D009369:Neoplasms / Q000401:mortality / Q000473:pathology* / Q000601:surgery*; D010865:Pilot Projects; D011379:Prognosis; D011446:Prospective Studies; D015996:Survival Rate