Table 2.

Univariate analysis of the prognostic factors related to the PFS after 2-day fraction GKRS for large brain metastasis

Prognostic factor	PFS (days)	p-value
Tumor volume, 20 mL		0.955
≤20 mL	239±32
>20 mL	230±32
Tumor volume, 15 mL		0.247
≤15 mL	199±3
>15 mL	239±37
50% isodose volume		0.839
≤18.8 mL	230±29
>18.8 mL	239±36
70% isodose volume		0.622
≤7.5 mL	238±48
>7.5 mL	235±26
80% isodose volume		0.846
≤3.3 mL	239±7
>3.3 mL	197±32
Peri-GKRS systemic treatment		0.741
Yes	239±50
No	230±29
Previous brain irradiation		0.019
Yes	85±55
No	238±4
Lung cancer primary		0.041
Yes	435±153
No	230±28

PFS : progression free survival, GKRS : Gamma Knife radiosurgery