Table 1.

Included study characteristics

Study	Publication Time	Years of Patient Accrual	Country	Study Type	No. of Patients	No. of Analysis	Median Follow Up	Histology	Adjuvant Therapies	EOR assessment	Level of Evidence
WINGE(9)	1989	1982–1987	London	retrospective study	285	187	NS	Glioblastoma multiforme 188 Astrocytoma 76 Mixed 11 Oligodendroglioma 10 Astrocytoma or mixed A > O 32	RT	NS	II
Shaw(10)	2002	1986–1994	Mayo	retrospective study	203	203	6.4 years	Oligodendroglioma or mixed O > A 69	RT	NS	II
HARMON J(11)	1993	1980–1985	USA (Michigan)	prospective randomized trial	60	60	4.5 years	Low-grade Glioma	RT + Ch	NS	II
Edward G(12)	1994	1960–1982	Mayo	retrospective study	71	71	15 years	Oligoastrocytoma	RT	operative report	II
R. Laws(13)	1984	1915–1975	Mayo	retrospective study	851	461	15 year MAX	Astrocytoma	RT	microscopically	III
LINDEGAARD(14)	1987	1953–1977	Norway	retrospective study	58	58	23 years MAX	Oligodendroglioma	RT	NS	III
SHAW(a)(15)	1989	1915–1975	Mayo	retrospective study	41	41	25 years MAX	Astrocytoma	RT	operative report	III
Soffietti(16)	1989	1950–1982	Italy	retrospective study	71	71	7 year MAX	Astrocytoma	RT	Surgeon’s description	III
North(17)	1990	1975–1984	USA(Baltimore)	retrospective study	32	32	69mo	Astrocytoma	RT	NS	III
SHAW(18)	1992	1960–1982	Mayo	retrospective study	82	82	7.1 years	Oligodendroglioma	RT	operative report	III
Shibamofo(19)	1993	1965–1989	Japan (Kyoto)	retrospective study	67	67	10 year MAX	Astrocytoma	RT + Ch	NS	III
Paolo(20)	1994	1953–1986	Italy	retrospective study	105	105	NS	Oligodendroglioma	RT	operative report	III
RAJAN(21)	1994	1974–1990	UK	retrospective study	82	82	52mo	Glioma	RT	operative report	III
Veelen(22)	1998	1975–1989	Netherlands	retrospective study	90	90	120mo Max	Astro 72 Oligo 14 Mixed 4	RT	patients’ charts	III
IWABUCHI(23)	1999	1967–1993	Japan	retrospective study	56	56	5 year	Astrocytoma	RT	NS	III
Smith(24)	2008	1989–2005	USA (California)	retrospective study	216	216	4.4 years	Astrocytoma 93 Oligodendroglioma 91 Mixed Oligoastrocytoma 32	RT + Ch	Patientrecords	III
Thomas B. Daniels(25)	2012	1984–2007	Japan	retrospective study	42	42	NS	Astrocytoma 27 Oligodendroglioma12 Oligoastrocytoma7	RT + Ch	Pre- and post-operative CT	III
Nicolato(26)	1995	1977–1989	Italy	retrospective study	76	74	160mo Max	Astrocytoma	RT	NS	IV
Jeremica(27)	1998	1988–1993	Japan	retrospective study	37	37	74mo	Astrocytoma 18 Oligodendroglioma 14 Mixed glioma 5	RT	operative report	IV
YEH(28)	2005	1985–1997	China (Taiwan)	retrospective study	93	93	110mo	Astrocytoma 46 Oligodendroglioma 32 Mixed 15	RT	operative report	IV

Note: NS Not stated, RT Radiation therapy, Ch chemotherapy not otherwise specified