Prognostic factors for survival and radiation necrosis after stereotactic radiosurgery alone or in combination with whole brain radiation therapy for 1–3 cerebral metastases

Table 2 Univariate and multivariate analysis on potential prognostic factors for overall survival after stereotactic radiosurgery, ns – not significant, CI – confidence interval

Factor	Number of patients	Median survival time in days	Univariate analysis		Multivariate analysis
Factor	Number of patients	Median survival time in days	95%-CI in days	p-value (unadjusted, log-rank)	p-value (adjusted, cox-regression)	Hazard ratio
Sex				0.013	0.042	1.31
• Male	159	235	172 – 298
• Female	181	327	274 – 380
• Overall	340	282	232 – 332
WBRT				0.049	ns (0.067)	1.28
• No	189	231	172 – 290
• Yes	151	341	280 – 402
• Overall	340	282	232 – 332
KPS				< 0.001	< 0.001	2.19
• ≤ 70	82	122	84 – 160
• > 70	258	342	298 – 386
• Overall	340	282	232 – 332
Histology				ns (0.488)
• NSCLC	160	275	218 – 332
• SCLC	27	231	151 – 331
• Melanoma	49	286	201 – 371
• Breast Ca	41	383	153 – 613
• RCC	20	184	0 – 435
• Others	43	265	36 – 582
• Overall	340	282	217 – 494
Age				ns (0.1)
• < 65 y	208	306	254 – 358
• ≥ 65 y	132	247	177 – 317
• Overall	340	282	232 – 332
Number of metastases				ns (0.764)
• 1	197	268	203 – 333
• 2	101	275	183 – 367
• 3	31	332	0 – 710
• 4	8	467	47 – 905
• 5	2	341	–
• 7	1	834	–
• Overall	340	282	232 – 332
Dose				< 0.001	ns
• ≤ 18 Gy	175	235	156 – 314
• > 18 Gy	165	351	255 – 447
	340	282	232 – 332
Volume				0.002	ns
• ≤ 2.5 ml	172	354	262 – 446
• > 2.5 ml	168	234	162 – 306
• Overall	340	282	232 – 332
RPA class				< 0.001
• I	26	1800	362 – 3238		< 0.001
• II	271	281	227 – 335		< 0.001	3.61
• III	43	130	17 – 243		0.001	3.85
• Overall	340	282

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