Table 3 Actuarial overall survival according to potential factors and the result of univariate and multivariate analysis

Gender

0.955

male

55

35

9.9

female

53

33

9.1

Age

0.777

< 57.5 years (median)

54

44

9.9

≥ 57.5 years (median)

54

24

6.3

NSCLC vs. Others

0.778

NSCLC

43

40

7.2

others

65

32

10.7

RPA

0.010

I

36

50

11.8

II

72

28

4.7

Extracerebral activity of primary tumor

0.001

0.001

not detectable

30

47

11.7

stable

25

48

10.0

progredient

53

23

4.0

Objective of therapy

0.217

primary

52

37

8.9

recurrence

56

34

10.0

Steroid uptake

0.005

0.030

yes

51

18

5.4

no

57

51

13.0

GTV

0.004

0.019

< 2 ccm

57

49

11.5

≥ 2 ccm

51

20

5.4

EQD2 (35 Gy)

0.021

0.298

≤ 35 Gy

24

13

3.6

> 35 Gy

84

42

10.7

EQD2 (median 39 Gy)

0.009

0.012

< 39 Gy

54

26

7.2

≥ 39 Gy

54

44

11.5

V4 Gy (median 16.7 ccm)

0.271

< 16.7 ccm

56

32

7.2

≥ 16.7 ccm

52

38

9.1

Time between diagnosis of primary and diagnosis of brain metastases

0.092

< 12.5 months

52

30

9.1

≥ 12.5 months

56

40

8.9