Files in /var/cache/rcd/patch_data/

Hello,

I have 1.6 GB of files in /var/cache/rcd/patch_data/. It is a
considerable number of rpms, and what appears to be a file for every patch
that's been applied to the server.

Is it required/necessary/advisable to leave this as is, or can these files
be deleted. The volume is at 83%, and it would be helpful if I could
knock that number down.

Thank you.

Sean