Cook sausage in a large skillet over medium heat until no longer pink; drain. Stir in 1/2 cup pizza sauce, 1 cup cheese and Canadian bacon.
Unroll crescent dough and separate into triangles. On an ungreased 14-in. pizza pan, arrange triangles in a ring with points toward the outside and wide ends overlapping at the centre, leaving a 4-in. opening. Press overlapping dough to seal.
Spoon filling onto wide end of triangles. Fold pointed end of triangles over filling, tucking points under to form a ring (filling will be visible).
Bake at 375° for 12-15 minutes or until golden brown and heated through. Sprinkle with remaining cheese. Bake 5 minutes longer or until cheese is melted. Serve with remaining pizza sauce.