Often used on the internet, cancer is a term given to anything shitty or annoying. The word "Aids" is also used in the same fashion, but doesn't have the same effect. Usually the word "fucking" comes before it in most uses.
A group of guys that are so ILL and do what ever they want. They'll steal your wife, girlfriend and ruin your life while bettering their own. They drink bottles of vodka like water every night and there is no stopping them
I got so CANCER shat last night that I ended up fucking my friends brothers girlfriend with another dude at the same time.