Survival and prognostic factors in patients treated with stereotactic radiotherapy for brain metastases

Figures & data

Table I. Patient and tumour characteristics (N = 198).

Characteristics	No. of patients/median
Gender
Female	126 (63.6%)
Male	72 (36.4%)
Age	61 years (range 25–85 years)
< 65 years	128 (64.6%)
≥ 65 years	70 (35.4%)
Primary tumour site
Lung cancer	95 (48%)
Breast cancer	34 (17.2%)
Renal cancer	23 (11.6%)
Malignant melanoma	13 (6.6%)
Colorectal cancer	13 (6.6%)
Other/unknown primary	20 (10.1%)
WHO performance status
0–1	176 (88.9%)
≥ 2	22 (11.1%)
Number of extracranial organs involved
0	120 (60.6%)
1	32 (16.2%)
2	26 (13.1%)
≥ 3	20 (10.1%)
Diameter of largest metastasis	20 mm (range 5–57 mm)
< 21 mm	106 (53.5%)
≥ 21 mm	92 (46.5%)
Number of brain metastases treated
1	128 (64.6%)
2	51 (25.8%)
3	17 (8.6%)
4	2 (1%)
Supra- or infratentorial location of metastases
Supratentorial	142 (71.7%)
Infratentorial	56 (28.3%)
SRT fractionation
1 fraction	121 (61.1%)
> 1 fraction	77 (38.9%)
Median dose per fraction
1 fraction	20 Gy [range 9–25 Gy]
3 fractions	9 Gy [4–10 Gy]
Clinical presentation
Seizures	35 (17.7%)
Neurologic deficit	125 (63.1%)
Headache	87 (43.9%)
Asymptomatic	22 (11.1%)
Systemic medical therapy < 2 months before brain dissemination
Yes	44 (22.2%)
No	154 (77.8%)
Time interval between primary and brain metastasis
< 1 year	108 (54.5%)
≥ 1 year	90 (45.5%)

Table II. Univariate analysis of overall survival according to primary tumour site and histology.

Factor	Median survival in months [95% CI]	Log rank test
Primary tumour site:
Lung/other sites (N = 95/103)	8.0 [6.0:10.0] vs. 7.0 [4.9:9.1]	p = 0.666
Breast/other sites (N = 34/164)	12.0 [7.8:16.2] vs. 6.0 [4.3:7.7]	p = 0.169
Renal/other sites (N = 23/175)	9.0 [4.6:13.4] vs. 7.0 [5.3:8.7]	p = 0.706
Melanoma/other sites (N = 13/185)	4.0 [1.9:6.1] vs. 7.0 [5.5:8.5]	p = 0.861
Colorectal/other sites (N = 13/185)	6.0 [< 0.0:14.2] vs. 7.0 [5.4:8.6]	p = 0.167
Other or unknown/other sites (N = 20/178)^§	4.0 [< 0.0:8.4] vs. 8.0 [6.3:9.7]	p = 0.246
Primary histology:
Adenocarcinoma/other histologies (N = 145/53)	8.0 [5.7:10.3] vs. 5.0 [2.6:7.4]	p = 0.502
Anaplastic carcinoma/other histologies (N = 14/184)	10.0 [< 0.0:22.8] vs. 7.0 [5.5:8.5]	p = 0.161
Melanoma/other histologies (N = 13/185)	4.0 [1.9:6.1] vs. 7.0 [5.5:8.5]	p = 0.861
Squamous cell carcinoma/other histologies (N = 12/186)	4.0 [< 0.0:9.1] vs. 7.0 [5.4:8.6]	p = 0.007
Non-small cell carcinoma NOS/other histologies (N = 10/188)	5.0 [1.9:8.1] vs. 7.0 [5.4:8.6]	p = 0.927
Other/other histologies (N = 4/194)*	3.0 [1.0:5.0] vs. 7.0 [5.5:8.5]	p = 0.119
Overall (N = 198)	7.0 [5.5:8.5]	N/A

NOS, not otherwise specified.

^§Other/unknown: Cardia cancer (N = 6), unknown primary (N = 6), ovarian cancer (N = 3), 1 bladder cancer, 1 cervix cancer, 1 oropharyngeal cancer, 1 rhinopharyngeal cancer and 1 sarcoma; *Other: Neuroendocrine carcinoma (n = 2), urothelial carcinoma (n = 1), sarcoma (n = 1).

Table III. Univariate analysis of overall survival according to other potential predictive factors.

Factor	Median survival in months [95% CI]	Log rank test
Male/female gender (N = 72/126)	7.0 [4.9:9.1]/7.0 [4.7:9.3]	p = 0.333
Age ≥/< 65 years (N = 70/128)	6.0 [4.4:7.6]/9.0 [6.2:11.8]	p = 0.013
WHO PS ≥/< 2 (N = 22/176)	2.0 [1.3:2.7]/9.0 [7.1:10.9]	p < 0.001
Number of involved extracranial organs		p = 0.038
0 (N = 120)	8.0 [5.6:10.4]
1 (N = 32)	7.0 [2.9:11.1]
2 (N = 26)	5.0 [2.5:7.5]
≥ 3 (N = 20)	4.0 [1.1:6.9]
Systemic treatment ≤/> 2 months before brain metastasis (N = 44/154)	7.0 [5.3:8.7]/7.0 [5.0:9.0]	p = 0.251
≤/> 1 year between primary diagnosis and brain metastasis (N = 108/90)	6.0 [4.6:7.4]/9.0 [5.0:13.0]	p = 0.189
Infratentorial/supratentorial location (N = 56/142)	8.0 [4.9:11.1]/6.0 [4.1:7.9]	p = 0.528
> 1 or 1 brain metastasis (N = 70/128)	9.0 [6.6:11.4]/7.0 [5.3:8.7]	p = 0.624
Largest metastasis ≥/< 21 mm (N = 92/106)	6.0 [4.8:7.2]/10.0 [7.5:12.5]	p = 0.024
> 1 or 1 fraction of SRT (N = 77/121)	6.0 [4.3:7.7]/9.0 [6.7:11.3]	p = 0.058

Table IV. Multivariate analysis of overall survival in months including the significant factors.

Factor	Hazard ratio	95% CI	Significance test
Age ≥ 65 years (N = 70)	1.55	[1.12:2.11]	p = 0.005
WHO PS ≥ 2 (N = 22)	3.39	[2.09:5.48]	p < 0.001
Largest metastasis ≥ 21 mm (N = 92)	1.51	[1.12:2.04]	p = 0.007
Involvement of one or more extracranial organs (N = 78)	1.40	[1.02:1.91]	p = 0.036

Figure 1. Survival according to number of unfavourable prognostic factors. Two patients still alive 124 and 96 months past SRT, respectively. PF, prognostic factors.