An Increase In The Diagnosis Rate Of Early Colorectal Cancer By Sample Targeting Using Stereomicroscopy

ObjectivesAccording to the pit pattern of colorectal lesion,we combined the application of magnifying colonoscopes,chromoendoscopy and examination under the stereomicroscopy after the the whole lump biopsy to investigate the detection rate of early ccolorectal cancer.Meanwhile,we divided neoplasms with a type-Ⅲ_L pit pattern into three subclasses and study the relationship between subclassification of the typeⅢ_L pit pattern and histopathology.To establish a set of standard pathological diagnosis method to raise the detection rate of early colorectal cancer.Materials and MethodsA total of 196 colorectal neoplasms(including 110 colorectal neoplasms with type-Ⅲ_L pit pattern) larger than 1.0cm in diameter were completely resected by polypectomy or endoscopic mucosal rection(EMR) and histopathologically in our hospital from August 2005 to July 2007.The inflammatory and hyperplastic polys with typeⅠandⅡpit pattern classified as nonneoplastic lesions were excluded. Submucosal tumours and squamous epithelial origin tumours were also excluded. Each specimen was both examined by targeting and localized biopsy under stereomicroscopy(Olympus,Tokyo,Japan) and conventional pathological examination, respectively.The suspicious parts associated with early colorectal cancer were sectioned under stereomicroscopy as experiment group,and the sections cut at random by conventional pathological examination as control group.The parameters (area,major axis,max-diameter,length,width) of subclasses of theⅢL pit pattern were measured using computer analysis.All specimens were diagnosed by two consultant histopathologists blinded to sample identity.The histopathological results of the suspicious parts with pit patterns associated with early colorectal cancer under stereomicroscopy were compared with conventional pathological examinations slicing the entire specimen at random.We divided neoplasms with a type-Ⅲ_L pit pattern into three subclasses(Ⅲ_L-AⅢ_L-B andⅢ_L-C),according to the morphologic and prominent stereomicroscopy findings.We examined the relation between these three subclasses and histology.Statistical analysis:SPSS11.5 is used as statistics analysis software,A P -value less than 0.05 was considered statistically significant.K Independent Samples Test was used to analyze histopathological diagnosis of the different colorectal lesions. McNemar test was used to analyze difference of diagnosis rate of early colorectal cancer between experiment group and control group.K Independent Samples Test was used to analyze the difference of pathology amount three subclassifications.One-Way ANOVA was used to analyze the parameters amount the three subclassifications.ResultsA total of 196 eolorectal neoplasms(135 male cases and 61 female cases,aged from 15 to 75 years old) which were 1.0-- 4.5cm in diameter were completely resected by polypectomy or endoscopic mucosal rection(EMR) and histopathologically in our hospital from August 2005 to July 2007.33.7%(66/196) of colorectal lesions were diagnosed as high-grade intraepithelial neoplasia by targeting and localized biopsy under stereomicroscopy.In contrast, only 6.1%(12/196) were found to be high-grade intraepithelial neoplasia by conventional histopathological examination.The diagnosis rate of high-grade intraepithelial neoplasia by stereomicroscopy was significantly higher than that of conventional pathological examination(P＜0.001)low intraepithelial neoplasia were dominant in tubular adenoma,about 88.0% (66/75),45.0%(36/80) of the tubulovillous adenomas were high-grade intraepithelial neoplasia,and 65.6%(21/32) of the villus adenomas were high-grade intraepithelial neoplasia.Villus adenoma was found significantly for diagnosed as high-grade intraepithelial neoplasia(P＜0.001).Subclasses of the typeⅢ_L pit pattern:(1) typeⅢ_L-A:oval pit,52 cases(47.3%) with type-Ⅲ_L pit patterns were judged to be subtypeⅢ_L-A,in which 80.8%(42/52) of the colorectal lesions were diagnosed as mild dysplasia histopathologically.(2) typeⅢ_L-B:long tubular and regular,46 cases(41.8%) were judged to be subtypeⅢ_L-B,in which 78.3%(36/46) of the colorectal lesions were diagnosed as moderate dysplasia histopathologically.(3) typeⅢ_L-C:slightly curved and irregular,12 cases (10.9%) were judged to be subtypeⅢ_L-C,and all of the colorectal lesions with the subtypeⅢ_L-C pit pattern were diagnosed as severe dysplasia histopathologically.Conclusions1.Sample targeting and localized biopsy under the stereomicroscopy and subclassification of the typeⅢ_L pit pattern can abviously improve the diagnosis rate of early colorectal cancer.2.We can differentiate neoplastic from non-neoplastic colorectal lesion by pit pattern.3.Established a set of standard pathological diagnosis method to raise the detection rate of early colorectal cancer.