Microbiome and Rectal Cancer

A flexible sigmoidoscopy is a procedure in which a flexible tubularized camera approximately 1 cm in diameter is inserted into the anus and advanced proximally to the sigmoid colon (approximately 20 cm). At that time a rectal biopsy of the tumor will be obtained as well as a sample from \>5cm proximal to the tumor, with a separate biopsy forcep. Tattoo injection, as standard of care, will be performed within 1 cm distal to the tumor to identify the location in the future or for surgical intervention. If there is inability to get proximal to the tumor then a location at least 5 cm adjacent in any direction will be sufficient so long as it is grossly normal appearing.