%0 Journal Article %T Development of Polyps and Cancer in Patients with a Negative Colonoscopy: A Follow-Up Study of More Than 20 Years %A R. J. L. F. Loffeld %J ISRN Gastroenterology %D 2014 %R 10.1155/2014/261302 %X Background. Adenomas are missed during colonoscopy. Aim. Assess the occurrence of colorectal cancer (CRC) and polyps in patients with a negative index colonoscopy (IC). Patients and Methods. All patients with a IC in 1992¨C1994, aged 40 and 60 years, were included. Exclusion criterion was presence of abnormalities, a family history, or surveillance. At the end of 2013 all records were studied in order to gather follow-up information. Results. 394 patients were included in four groups: group 1 patients who died, group 2 patients who were not in the hospital systems anymore, group 3 patients still visiting the hospital but not the department of gastroenterology, and group 4 patients undergoing new colonoscopies. In group 1, 2 patients died of CRC and 4 developed a polyp. No data were available from the patients in group 2. Patients in group 3 visited the outpatient clinics but did not undergo new colonoscopy. Patients in group 4 underwent additional colonoscopies. The yield was 35 patients polyps and three CRCs. Five patients (1.3%) developed CRC, and 39 (9%) developed a polyp. Conclusion. Given these results the number of potentially missed adenomas in IC is very low and the consequences of missed adenomas are highly exaggerated. 1. Introduction According to the literature many adenomas are missed during routine endoscopic investigation of the colon [1, 2]. This leads to the assumption that many potential future cancers are being missed. The miss rate of adenomas is reported to exceed 20% in back to back endoscopic investigations. Is this miss rate indeed responsible for interval cancers? Obviously, the answer to this question is yes. This will certainly be the fact in patients with positive family history of colorectal cancer and patients belonging to families with the Lynch syndrome [3]. Is this also true for patients with a normal risk of developing colorectal cancer? Or will all these missed adenomas eventually become cancer? Is the risk of development of colorectal cancer due to missed adenomas exaggerated in normal daily practice [4]? In order to try to answer these questions, a study was done in patients who underwent colonoscopy for the normal obvious clinical reasons, in whom no significant findings were diagnosed, in order to ascertain the development of polyps and colorectal cancer in many years to follow. 2. Patients and Methods All patients undergoing colonoscopy in the years 1992¨C1994 in the Zaans Medisch Centrum, the community hospital of the Zaanstreek region in the Netherlands, were studied. Patients underwent endoscopy for normal %U http://www.hindawi.com/journals/isrn.gastroenterology/2014/261302/