A lot of spammers use modified words to get throuth spam filters. What they do is take a word like ‘casino’ and insert a random character into it. For example ‘ca!sino’. If you get a lot of spam with words modifed like this, then you can use sa_patgen.pl to generate pattern rules for SpamAssassin.
All you have to do is specify the score to add for each modified word match (I use 0.5) and a list of words like casino, gambling, viagra, etc. The script will output a set of rules to match modified words. You can save the output in your local.cf file or pipe it somewhere else.