Additional radiation boost to whole brain radiation therapy may improve the survival of patients with brain metastases in small cell lung cancer

Table 3 Survival-related factors on OS in multivariate analysis

Characteristics	HR of death (95% CI)	P value
WBRT vs. WBRT plus boost	0.681(0.473–0.958)	0.031^*
Number of BM	1.034(0.719–1.288)	0.795
KPS	1.014(0.970–1.061)	0.535
Symptomatic BM (no vs. yes)	2.433(1.302–4.546)	0.005^*
Maximum diameter of the largest tumor	1.420(1.124–1.794)	0.015^*
Extracranial disease (control vs. progression)	2.234(1.158–4.310)	0.016^*

*p < 0.05 was considered significant. WBRT whole brain radiotherapy, BM brain metastases, KPS Karnofsky performance score, RT radiation therapy