Table 1 Clinicopathological characteristics of included cohorts

Sex

 Male, n (%)

33 (63%)

15 (39%)

9 (36%)

7 (50%)

NA

 Female, n (%)

19 (37%)

23 (61%)

16 (64%)

7 (50%)

NA

Histology

 Adenocarcinoma, n (%)

41 (79%)

29 (76%)

25 (100%)

9 (64%)

25 (100%)

 Squamous carcinoma, n (%)

5 (9%)

4 (11%)

0

4 (29%)

0 (0%)

 Adenosquamous carcinoma, n (%)

3 (6%)

0

0

0

0

 Large cell neuroendocrine tumor

2 (4%)

0

0

0

0

 Small cell carcinoma

0

0

0

1 (7%)

0

 Sarcomatoid carcinoma

1 (2%)

0

0

0

0

 Not otherwise specified

0

5 (13%)

0

0

0

Pathology stage at initial diagnosis

 I, n (%)

9 (17%)

1 (3%)

3 (12%)

1 (7%)

8 (32%)

 II, n (%)

14 (27%)

17 (45%)

5 (20%)

3 (21%)

1 (4%)

 III, n (%)

9 (17%)

9 (24%)

5 (20%)

5 (36%)

3 (12%)

 IV, n (%)

20 (38%)

0 (0%)

11 (44%)

1 (7%)

13 (52%)

 NA, n (%)

0 (0%)

11 (29%)

1 (4%)

4 (29%)

0 (0%)

Age at diagnosis of primary tumor (median, range)

57.5 (29.0–72.0)

60.7 (40.5–79.6)

60.0 (34.0–84.0)

NA

NA

Age at date of craniotomy (median, range)

59.5 (29.0–76.5)

NA

NA

60.6 (48.3–78.1)

NA

BrM progression-free in years (time between diagnosis of primary tumor and BrM, median, range)

1.4 (− 0.2–8.0)

0.4 (− 0.5–5.0)

NA

2.4 (0.5–5.0)

NA

Brain radiation therapy

 Yes, n (%)

9 (17%)

5 (13%)

4 (16%)

2 (14%)

NA

 No, n (%)

43 (83%)

33 (87%)

21 (84%)

12 (86%)

NA

Steroid agents prior to craniotomy

 Yes, n (%)

41 (79%)

NA

NA

14 (100%)

NA

 No, n (%)

11 (21%)

NA

NA

0 (0%)

NA

Median OS with range (Primary to censored in months)

50.9 (6.0–144.0)

13.2 (1.2–110.4)

NA

41.0 (11.2–101.1)

NA

Median OS with range (Craniotomy to censored in month)

29.0 (2.5–132.0)

NA

NA

7.5 (0.3–61.1)

NA