apache - Mod_rewrite last part of url only -

i have url:

http://www.mysite.com/forum/topic/1234 

i need rewrite to:

http://www.mysite.com/forum/topic/1234-this-is-a-test 

here have:

<ifmodule mod_rewrite.c> options -multiviews rewriteengine on rewritebase /forum/  rewriterule ^topic/([0-9]+)$ topic/$1-this-is-a-test [l] </ifmodule> 

nothing happens. ideas?

you got right, add r flag:

rewriterule ^topic/([0-9]+)/?$ topic/$1-this-is-a-test [l,r]