Table 2.

Outcome Estimates

Outcome by time	PCI (n = 163)			Observation (n = 177)			P*
	No. at Risk	Survival/Failure Estimate (%)	95% CI (%)	No. at Risk	Survival/Failure Estimate (%)	95% CI (%)
Overall survival
6 months	149	93.2	88.1 to 96.2	160	92.0	86.9 to 95.2	.86
12 months	115	75.6	68.1 to 81.5	129	76.9	69.9 to 82.5
MST, months	25.8			24.8
95% CI	22.6 to 31.3			20.5 to 27.4
No. of patients who died	90			100
HR of observation v PCI arm	1.03
95% CI	0.77 to 1.36
Disease-free survival
6 months	119	74	66.5 to 80.1	121	69.7	62.2 to 75.9	.11
12 months	86	56.4	48.4 to 63.7	86	51.2	43.5 to 58.3
MDFST, months	13.8			12.3
95% CI	11.6 to 18.8			10.5 to 13.1
No. of patients who experienced failure	108			132
HR of observation v PCI arm	1.23
95% CI	0.95 to 1.59
CNS metastasis
6 months	145	3.3	1.4 to 7.6	144	10.7	6.9 to 16.5	.004
12 months	109	7.7	4.3 to 13.4	113	18.0	12.9 to 24.9
MCNSMT, months	Not reached	Not reached
95% CI
No. of patients who experienced failure	15			36
HR of observation v PCI arm	2.35
95% CI	1.29 to 4.30

NOTE. HR quantifies how much more or less risk patients at some level have than those at the reference level. CI that includes 1 indicates that no difference exists between the subgroups.

Abbreviations: PCI, prophylactic cranial irradiation; MST, median survival time; HR, hazard ratio; MDFST, median disease-free survival time; MCNSMT, median CNS metastasis time.

^*From stratified log-rank test.