How to prevent cscope rebuilt every time in emacs

[Neal]

Hi All,
I just tried to integrate the cscope with my emacs, but there's a
problem: after creating the cscope.out, everytime I use cscope to find
definition or symbol, the cscope.out is rebuilt.

Is there any way to prevent emacs to do so (it's time wasting and
annoying)? Or have I missed something in my emacs configuration file?

Thanks