| Objective:1. Investigate the clinical, endoscopic and pathologicalcharacteristics of sessile polyps in right-sided colon, especiallyright-sided sessile serrated adenoma, to improve the recognization andattention to this new type of precancerous lesion for endoscopists andclinicians.2. Investigate BRAF mutation of serrated polyps inright-sided colon. Methods:（1）Retrospectively collected the data (fromJan.2005to Dec.2012) at the endoscopic center of the Affiliated Hospitalof Luzhou Medical College, and the clinical,pathological and endoscopicinformation of every patients.（2）When right-sided colonic lesions werefound in patients undergoing colonoscopyat the department of endoscopiccenter (from Jan.2013to Mar.2013), white-light endoscopy, narrow-bandimaging and chromoendscopy were used to observe them carefully.(3)We Reviewed the HE slides of colonic polyps at the PathologicalDepartment of the Affiliated Hospital of Luzhou Medical College (fromJan.2008to Dec.2012). The prevalence and histologic features ofright-sided sessile serrated adenoma were explored.(4)The endoscopistsin our endoscopic center were divided into two groups (A and B). Thedetection rate of the right-sided sessile polyps among the two groupswere compared.（5）We collected140fresh specimens of colonic lesions(from Jan.2005to Dec.2012) at the department of endoscopic center.Histologcal type of each specimen was confirmed by pathological diagnosis, including20right-sided sessile polyp,20right-sided traditionaladenomas,20right-sided colon cancers,20left-sided sessile polyps,20left-sided traditional adenomas,20left-sided colon cancers, while20normal colonic tissues were used as control. BRAF mutation wereanalysed by direct sequencing in these samples. Results:（1）Clinicalpathological characteristics of right-sided colon cancer:A total of18209colonoscopic procedures were performed, the detection rate ofleft-sided colon cancer was6.2%（1130/18209）, the detection rate ofright-sided colon cancer was2.5%（461/18209）. A total of1591CRCswere detected. The detection rate of CRC increased with the patients ages.The detection rate of right-sided colon cancer didn’t decrease in recentyears. The detection rate of right-sided colon cancer increased witholder age and the proportion was higher in males than in females. Thelocation sites of right-sided colon cancer was scattered most in theascending colon (46.6%), the hepatic flexure of the colon（17.1%）andtransverse colon (27.8%), but less in the cecum (8.5%). The location sitesof left-sided colon cancer was relatively concentrated, mainly located inrectum (69.6%), followed by sigmoid colon (20.2%). Location of rectumand sigmoid colon accounted for nearly90%of all left CRCs. Inright-sided colon cancer，highly differentiated cancer accounted for32.9%(71/216), moderately differentiated cancer accounted for46.3%（100/216）, poorly differentiated cancer accounted for20.8%（45/216）.In left-sided colon cancer，highly differentiated cancer accounted for 51.1%(295/577), the moderately differentiated cancer accounted for38.5%(222/577),poorly differentiated cancer accounted for10.4%(60/577).Histopathological findings revealed that poorlydifferentiated tumors were frequently seen in the right colon and betterdifferentiated tumors were frequently seen in the left colon.（2）Thedetection rate of right-sided colon sessile polyps. In a total of18209colonoscopic procedures, the detection rate of colon polyps was23%（4183/18209）, and the detection rate of right-sided colon sessile polypswas4.7%(852/18209). There was no significant differences in detectionrate between male and female patients (P＞0.05). The detection rate ofright-sided colon sessile polyps increased with older age. Of the247right-sided colon sessile polyps from2005to2008,52cases wereHPs（0.8%）,43cases were TAs（0.6%）. Of the605right-sidedcolon sessile polyps from2008to2012,142cases were HPs（1.2%）,160cases were TAs（1.4%）. In recent years the detectionrate of HP in right-sided colon sessile polyps was increased (P <0.05).（3）The applications of new endoscopic technology in the screening ofright-sided colon sessile polyps. We found that the NBI andchromoendoscopy can improve the observation of the colorectal mucosalstructure and capillary patter, compared with white light endoscopy.（4）Pathological features and the prevalence of SSA. For the period fromJanuary2008to November2012, we identified retrospectively51SSAsamong5232colorectal polyps. SSAs accounted for4.9%(51/1046) of serrated polyps and1.0%of all colorectal polyps.64.7%(33/51) of theseSSAs were located in the right colon. The mean age of the patients withSSAs was56.3year and female35cases (68.6%). It has been noted thatSSAs is frequently observed in women and in the right colon.（5）Differences among examiners in the detection rates of right-sided colonsessile polyps. In Group A, the detection rate of colon polyps was22.7%(2110/9308), right-sided colon sessile polyps4.3%(400/9308), andright-sided colon cancer2.8%(258/9308). The mean colonoscopicwithdrawal time was3.2±0.6minutes. In Group B, the detection rate ofcolon polyps was33.4%(736/2207), right-sided colon sessile polyps6.7%(148/2207), and right-sided colon cancer2.5%(55/2207). The meancolonoscopic withdrawal time was4.5±1.0minutes. There was nosignificant difference of the detection rate of right-sided colon cancerbetween group A and group B（P＞0.05）. However, the detection rateof right-sided colon sessile polyps in group B was significantly higherthan that in group A（P＜0.05）.The endoscopists in group B had longerwithdrawal times for the colonoscopy compared with that in group A（P＜0.05）（.6）The mutation rate of BRAF in the right-sided sessile polyps.The mutation rate of BRAF of right colon in normal colonic tissues,sessile polyps, colon adenomas, colon cancers were0%,0%,5%,respectively. Only one of twenty CRC in right colon harboredBRAF mutation,the mutation rate is5%(1/20). Conclusions:1. Thedetection rate of colon cancer in the right colon is lower comparison tothat in the left colon. Histopathological findings revealed that poorly differentiated CRCs are more common in the right colon compared withthat in left colon.2. The prevalence of right-sided colon sessile polypswas much lower in some Chinese patients comparison to that in Westernpatients. A considerable part of the right-sided colon sessile polyps mightbe missed during colonoscopy.3. New endoscopic technologies such asnarrow-band imaging and chromoendscopy may improve the detectionrate of right-sided colon sessile polyps.4. SSA has not been wellrecognized by most Chinese endoscopists and pathologists. Most Chineseendoscopists and pathologists should pay more attention to sessileserrated adenoma, in order to improve the detection rate of it.5. Anappropriate increase in the colonoscopic withdrawal time may improvethe detection rate of right-sided colon sessile polyps.6. The BRAFmutation rate of right-sided serrated adenoma in some Chinese patientswas much lower comparison to that in Western patients. |
PDF Full Text Request