Methods for treating diseases of the rectum or colon are provided. The methods can comprise accessing the rectal mucosa through a trans-anal approach performing a mucosectomy to remove mucosal tissue from at least a portion of the rectal or colonic wall and securing a flexible scaffold material to a region of the rectal or colonic wall from which mucosa has been removed, wherein the scaffold material is selected to facilitate cellular ingrowth and formation of new mucosal tissue.
