Table 4.

Literature review of aggressive meningiomas treated by gamma knife

Author, year	WHO grade	Patient number (lesions)	Marginal dose (Gy)	Max dose (Gy)	Control rate	Progression free survival	Overall survival	Statistically significant prognostic factors on multivariate analysis
Ojemann et al., 2000 [20]	3	19 (31)	Mean 16	18		5 year 26%	5 year 40%	PFS and OS: age (p < 0.003), tumor volume (p < 0.05)
Stafford et al., 2001 [21]	2	13	Median 16	36	5 year 68%		5 year 76%*
	3	9			5 year 0%		5 year 0%*
Harris et al., 2003 [22]	2	18	Mean 14.9	29.4		5 year 83%	5 and 10 year 59%	PFS: early SRS (p < 0.001), small tumor volume (p < 0.001)
	3	12	Mean 15.7	31.4		5 year 72%	5 year 59% 10 year 0%	OS: younger age (p = 0.03)
Huffmann et al., 2005 [23]	2	15 (21)		18	6 months 93%		100% at median follow up of 35 months
Kondziolka et al., 2008 [24]	2	54			50% at median of 2 years
	3	29			17% at median of 15 months
Attia et al., 2012 [25]	2	24	Median 14	18	1 year 75%	2 year 40%	1 year 92%	PFS: dose > 14 Gy (p = 0.01)
					2 year 51%	5 year 25%	2 year 67%
					5 year 44%		5 year 52%
Mori et al., 2013 [26]	2	19 (22)	Mean 16.5	20.15	1 year 74%,
	3	4
					2 year 54%,
					3 year 34%
Tamura et al., 2013 [27]	2	9	Mean 18.8	37				Stabilization of tumor growth: small lesion volume (p = 0.02), marginal dose (p = 0.04), max dose (p = 0.02)
	3	7
Current series	2	31	Median 18	24		1 year 95.7% 3 year 70.1%	1 year 92.4% 3 year 83.4%	Recurrence: WHO grade 2 histology (p = 0.0134)
	3	4				1 and 3 year 0%	1 and 3 year 33.3%	OS: WHO grade 2 histology (p = 0.0386), treated tumor volume (p = 0.0095)

*Cause specific survival.