Colorectal neoplasms in symptomatic patients without evidence of bleeding: a prospective study in an Iranian population

BACKGROUND: Colorectal cancer (CRC) is a preventable disease with a high mortality and morbidity. Data on its prevalence are lacking in Iran, as well as for adenomatous polyps. This study was conducted to estimate prevalence of CRC in patients with long lasting colonic symptoms (except for known risk factors for cancer and those with rectal bleeding) who underwent total colonoscopy. METHODS: This prospective study was carried out in Imam Hospital, Tabriz University of Medical Sciences, Iran. The recruitment procedure involved 228 individuals aged more than 30 who visited a gastroenterologist because of lower gastrointestinal tract symptoms and had criteria for a colonoscopy. The endoscopist visualized the caecum in all, documented by a photo of caecum and/or specimen of the terminal ileum. The Chi square test and multiple logistic regression analysis were used to determine the significance of associations between different symptoms and colonoscopic findings. RESULTS: Thirty four subjects (14.9%) were found to have colorectal neoplasia and 112 (49.1%) had a completely normal colon. Adenomatous polyps were detected in 27 patients, which included 15.6% of men and 7.0% of women. Most of them were tubular (58.3%) and severe dysplasia was reported in only 3 cases (11.1%). Mean age of patients with a polyp (51.1+/-12.5 years) was not significantly different compared to others (p=0.381) nor mean duration of symptoms (21.1 months, p=0.435). Cancer was detected in 7 (3.1%) of our study population, the mean age of 65.7+/-6.0 years in this case being significantly elevated (p<0.0005). None of the symptoms were predictors of cancer or polyps. This result was the same by a multivariate analysis including age, gender and duration of the symptoms. CONCLUSION: The low prevalence of colorectal neoplasms as well as the less advanced pattern of adenomas in Iran are compatible with other data from Asia and the Middle East, contrasting with western countries.