Spam filtering without downloading the whole message

I use fetchmail sendmail and procmail to handle incoming mail. In the
last 3 days I've received 2 300K+ spam mails. I've currently got
procmail punting these off into a spam box (filtering on the from
address). Is there any way I could have killed these without having
to completely download them first? (My ISP doesn't do any server-side
filtering). 

TIA
-- 
Stephen Patterson http://www.lexx.uklinux.net/
s(_dot_)patterson(_at_)SPAM(_dot_)freeuk(_dot_)com (remove spam to reply)
ICBM address 54-22-0N 0-28-0W  Linux Counter No: 142831 
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