A surgical instrument comprising an end effector is disclosed. The end effector comprises a staple cartridge including a cartridge body comprising an annular array of staple cavities, staples removably stored in the staple cavities, a firing drive configured to eject the staples from the staple cavities, and a cutting member circumscribed by the staple cavities. The end effector further comprises an anvil including a tissue compression surface, forming surfaces configured to deform the staples and a tissue block. The anvil is movable toward the cartridge body to compress tissue between the cartridge body and the tissue block and the cutting member is configured to incise the tissue and the tissue block during a cutting stroke of the cutting member.
