The colon contains many different kinds of bacteria that are essential to good health and function of the gastrointestinal tract. Rush University Medical Center is investigating the differences in bacteria both prior to and after bowel preparation for endoscopic procedures. Participants will undergo a limited flexible sigmoidoscopy (does not require sedation or bowel preparation) three to seven days prior to their clinically prescribed colonoscopy for colon cancer screening. Small tissue samples called pinch biopsies will be taken during both procedures, allowing investigators to isolate and examine bacteria throughout the colon.  Biopsy sampling is a frequent clinical procedure. 

Patients will be reimbursed $50 for their participation in the study. It is recommended that persons over the age of 50 and at average risk for colon cancer undergo a colonoscopy.        

You may be eligible for this study if you are not currently experiencing any gastrointestinal symptoms but are having a screening endoscopy for colon cancer surveillance at Rush University Medical Center.

Patients with the following criteria will be excluded from participating:

1. Patients with bleeding disorders
2. Patients with extensive colonic or ileocolonic resection
3. Patients with ileostomies or colostomies
4. Patients on antibiotics (including sulphasalazine), herbal remedies or diet therapies during the study
5. Patients with any symptomatic, organic GI disease other than hemorrhoids and hiatal hernia
6. Preexistent organ failure or comorbidities, as these may change GI flora
7. Obesity (body mass index greater than 30)
8. Presence of short bowel syndrome or severe malnutrition with ideal body weight below or equal to 90%. 
9. Estimated survival of less than one year and Karnofsky performance status less than 50%
10. Desire to start smoking during the study
11. Any endoscopic or histological evidence of active disease or infection
12. Patients lacking decisional capacity

For more information or to determine if you are eligible to participate, please call the number provided. If you choose to inquire via e-mail, please refer to the study title in your message.