You can use the summary method for a survfit object from the package
survival as in the following example:
> library(survival)
> summary( survfit( Surv(futime, fustat)~rx,data=ovarian), times=500)
Call: survfit(formula = Surv(futime, fustat) ~ rx, data = ovarian)
rx=1
time n.risk n.event survival std.err lower 95%
CI
500.000 5.000 6.000 0.538 0.138
0.326
upper 95% CI
0.891
rx=2
time n.risk n.event survival std.err lower 95%
CI
500.000 7.000 4.000 0.658 0.141
0.433
upper 95% CI
1.000
Matt Austin
Statistician
Amgen
One Amgen Center Drive
M/S 24-2-C
Thousand Oaks CA 93021
(805) 447 - 7431
> -----Original Message-----
> From: r-help-bounces at stat.math.ethz.ch
> [mailto:r-help-bounces at stat.math.ethz.ch]On Behalf Of Lisa Wang
> Sent: Monday, December 06, 2004 8:27 AM
> To: R-Help
> Subject: [R] The survival rate at a certain time
>
>
> Hello there,
>
> I am doing analysis on survival data. How do I pick out a
> probability of
> survival at a chosen landmark time(for example, 3 years, 4 years) from
> the result of "survfit"? or any other functions? As I know, the
result
> of 'survfit' only have the probabilities for all event or cencor
time.
>
> Thank you very much
>
> Lisa Wang
>
> Princess Margaret Hospital
> Toronto, Ca
>
> tel: 416-946-4501 ext.5201
>
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