Not at the moment other than through environment variables. I do not see any reason why it could not be supported since other Cadence tools do. Please file an SR if env variables are not adequate for your goal
I've wondered the same. The only way I know of is via shell environment variables.
$ setenv FOO bar
SETUP> echo $FOO
TCL_SETUP> puts $env(FOO)
A user made wrapper script around lec could provide this feature too.