I found this quote on a blunt information article!
The "Cancer Paper" is a name given to parts of a (usually Philly, Swisher, Dutch Master, or the more recent Game) blunt with extra paper and/or glue that make blunts harsher tasting. It is named the "Cancer Paper" because it is believed that the extraneous material poses unnecessary health risks. The first is found on the inside of the outer leaf at the mouth of the cigar. The paper is approx. 1 inch and is to reinforce the cigar. In a properly rolled blunt, this paper should be removed because it is unneeded and adds harshness. Removal of this paper can prove daunting for novice blunt rollers so you may want to have some spares on hand.