Screening Colonoscopy from a Large Single Center of Thailand - Something Needs to be Changed?

Abstract

Background: Results of screening colonoscopy from Western countries reported adenoma detection rates (ADRs) of 30-40% while those from Asia had ADR as low as 10%. There have been limited data regarding screening colonoscopy in Thailand. The objectives of this study were therefore to determine polyp and adenoma detection rates in Thai people, to evaluate the incidence of colorectal cancer detected during screening colonoscopy and to determine the endoscopic findings of the polyps which might have some impact on endoscopists to perform polypectomy. Materials & Methods: This study was a retrospective electronic chart review of asymptomatic Thai adults who underwent screening colonoscopy in our endoscopic center from June 2007 to October 2010.Results: A total of 1,594 cases were reviewed. The patients had an average age of 58.3±10.5 years (range 27-82) and 55.5% were female. Most of the cases (83.8%) were handled by staff who were endoscopists. A total of 488 patients (30.6%) were reported to have colonic polyps. Left-sided colon was the most common site (45.1%), followed by right-sided colon (36.5%) and the rectum (18%). Those polyps were removed in 97.5% of cases and 88.5 % of the polyps were sent for histopathology (data lost 11.5%). Two hundred and sixty three cases had adenomatous polyps, accounting for 16.5 % ADR. Advanced adenomas were detected in 43 cases (2.6%). Hyperplastic polyps were mainly located distal to the splenic flexure of the colon whereas adenomas were found throughout the large intestine. Ten cases (0.6%) were found to have colorectal cancer. Four advanced adenomas and two malignant polyps were reported in lesions ≤ 5 mm. Conclusion: The polyp detection rate, adenoma detection rate, advanced adenoma detection rate and colorectal cancer detection rate in the screening colonoscopy of Thai adults were 30.9%, 16.5%, 2.6% and 0.6% respectively. Malignant transformation was detected regardless of the size and location of the polyps. Therefore, new technology would play an important role indistinguishing polyps.

Prevalence of Colorectal Polyps in a Group of Subjects at Average-risk of Colorectal Cancer Undergoing Colonoscopic Screening in Tehran, Iran between 2008 and 2013

“…Researchers from Asian-pacific developed countries have also reported a significant increase of CRC over the last decades. It seems that these countries actually have the same incidence as western countries; this could be due to the "westernization" of lifestyles in these countries (Choe et al, 2007;Chung et al, 2010;Aswakul et al, 2012;Ng and Wong 2013;Yang et al, 2014). This discrepancy between our findings and theirs might be related to lifestyle, diet, younger population and also genetic differences.…”

High Rate of Advanced Colorectal Polyps in a 10-Year-Long Retrospective Study in Qazvin, Iran

“…This finding was in contrast with the study by Aswakul et al, 2012 that showed only 2.6% of polyps were advanced.…”

“…Also, about 14% of the polyps in an Iranian study by Zare-Mirzaie et al, 2013 had high-grade dysplasia. Like the study by Aswakul et al (2012), the present research found no relationship between advanced adenoma and sex and age. Likewise, Zare-Mirzaie et al (2013) reported no relationship between sex and age on the one hand and high-grade dysplasia on the other.…”

“…Also, in a study in the USA (Lowenfels et al, 2011), over 50% of polyps were less than 5mm long, and polyps with a length of more than 15mm made up just under 5% of all the polyps observed. Furthermore, a study in Thailand (Aswakul et al, 2012) showed that over 70% of polyps detected in adults via colonoscopy for screening purposes were less than 5mm long.…”

Feasibility of Computed Tomography Colonography as a Diagnostic Procedure in Colon Cancer Screening in India

“…Many have discussed the variation in sensitivity and specificity of CTC results when compared to the Colonoscopy. CTC mainly fails in identifying the smaller lesions of <5mm (Aswakul et al, 2012). Colonoscopy overtakes CTC in highly risk population as CTC fails for smaller lesions (Broadstock, 2007).…”