Assessment of Magnifying Colonoscopy with Chromoscopy in the Differential Diagnosis of Neoplastic and Non-Neoplastic Lesions of the Large Bowel

Abstract

Colorectal cancer (CRC) remains a major health problem due to its high incidence and mortality. Better chances of cure occur with early diagnosis, but this is not common for the majority of cases. CRC has an identifiable benign precursor and its detection and removal prevents deaths for the disease. Screening and early diagnosis are the main strategies to reduce CRC mortality. Conventional colonoscopy (CC) represents the best method for early diagnosis of CRC and for diagnosis and treatment of precursor lesions. Nevertheless CC has miss rates well known for the diagnosis of polyps and cancer. Magnifying colonoscopy (MC) has been used with the purpose of increasing the performance of CC. Its main advantage remains on the possibility of differentiating neoplastic from non-neoplastic lesions through magnified view of intestinal opening of bowel crypts, in order to prevent resection of non-neoplastic lesions, and this capability may reduce costs and risks related to endoscopic resections. The aim of this study was to evaluate the accuracy of magnified observation of pit pattern in polypoids and flat colorectal lesions during MC with cromoscopy in relation to histopathologic diagnosis of colorectal neoplastic and non-neoplastic lesions. From April 2002 to October 2003, 120 patients were included in the study and 200 lesions were detected. Endoscopic diagnosis was obtained for all lesions through magnified (up to 200X) observation of intestinal crypt opening and pit pattern was determined according to Kudo's classification. All lesions were excised or biopsied. Sixty five (54.2%) patients were women. Mean age was 58.8 years. 137 (68.5%) lesions were located at the left colon and rectum. 117 (58,5%) lesions had sessile morphologic aspect and 64 (32%) were flat. 136 (68%) had diameter under 5 mm. 125 lesions (62.5%) were MC classified as non-neoplastic and 75 (37,5%) as neoplastic lesions. 106 (53%) were histopathologically classified as non-neoplastic and 94 (47%) as neoplastic lesions. 31 (33%) of the 94 lesions classified histopathologicaly as neoplastic were mixed adenomas. The accuracy of MC in the differentiantion of neoplastic from non-neoplastic lesions in relation to histopathology was 78.5% and difference was statistically significant (p < 0.0001). The conclusion of the study is that MC cannot replace histopathological examination for the differential diagnosis between neoplastic and non-neoplastic lesions of the large bowel.