## Estimate Median Survival Time

Regular Contributor
Posts: 239

# Estimate Median Survival Time

I have been given a hazard ratio = 0.64 and a control median of 8 months.  How can I use that information to estimate the treatment median survival time at 80% power and show 38% improvement in hazard ratios?

Posts: 2,655

## Estimate Median Survival Time

Check out PROC POWER, and look at the syntax for TWOSAMPLESURVIVAL.  I am pretty sure that you just need to plug in the values, and exponentiate the hazard rate for the reference group.  There is an example 70.6 in the SAS/STAT 9.3 documentation to get started.

Steve Denham

Posts: 2,116

## Estimate Median Survival Time

I don't think that you can do both of those from the little information you have provided.  See

http://www.statsdirect.com/help/sample_size/sample_size_for_survival_analysis.htm

for an easy to use survival analysis sample size computation.

Given the ratio and one rate, you can compute the sample size required for 80% power.

You can compute a 38% "improvement in hazard ratios" (though it is not to me well defined) to get a new HR, and then do the computation above.

I believe the SAS Power and Sample Size product can do the can computations.

Doc Muhlbaier

Duke

Regular Contributor
Posts: 239

## Estimate Median Survival Time

I guess I should have specified that we already have a sample size of 200.  I hope that clears up a little bit.

Posts: 2,655