| BackgroundColorectal cancer(CRC)is a one of the malignant tumors of digestive tract which have a serious threat to human health,and in the world,the incidence of it ranks third in malignant tumors.In 1975,Muto proposed a classic pathway,namely,adenoma-adenocarcinoma pathway,and since then,adenomas were considered the only type of polyp with malignant potential.Nowadays,with the development of endoscopic techniques,the progress of molecular genetics and the change of pathological diagnostic standards,the importance of serrated lesions in the pathogenesis of CRC has caused more and more attention.Distinct from the classical pathway,CRC can arise from serrated lesions via the serrated pathway,which involves CpG island methylation,microsatellite instability,BRAF and KRAS gene mutation and other molecular mechanisms.Serrated lesions are a group of heterogeneous lesions which have serrated morphological structure in the crypt epithelium.The family of serrated lesions comprises hyperplastic polyp(HP),sessile serrated adenoma/polyp(SSA/P)and traditional serrated adenomas(TSA).Compared to HP,TSA and SSA/P have cytological characteristics which could more easily transform to malignancy,especially SSA/P.Many scholars believe currently the high incidence of CRC is mainly associated with lack of understanding of SSA/P under colonoscopy,therefore,early recognizing SSA/P and timely complete removing it is of great significance for preventing CRC.However,at present,serrated lesions were rarely reported in China,especially in the lack experience of the recognition of SSA/P in the clinical practice.ObjectiveThe objective of this study was to summarize the clinical,endoscopic and pathological features of serrated lesions,comparing the endoscopic characteristics of different pathological types,and explore the change of serrated lesions and SSA/P detection rate in different age groups and gender,and the correlation of different subtypes and advanced adenoma,further providing reference for clinical works associated with diagnosis and treatment.MethodIn this study,we selected patients diagnosed with colorectal serrated lesions as the research objects from patients which underwent colonoscopy at Endoscopy Center of the Second Hospital of Shandong University from September 2013 to May 2016.The clinical,endoscopic and pathological data were retrospectively analyzed.SPSS 20.0 software was used to analyze the data.Demographic characteristics of patients with HP and patients with SSA/P,and the endoscopic characteristics of different pathological types of serrated lesions were compared by χ2 test.Clinical and pathological characteristics of patients which have serrated lesions with or without advanced adenoma were compared by Fisher’ exact probability test.Result1.The detection rate of serrated lesions was 3.2%(232/7332),and detection rate in male was higher than female(3.7%vs.2.4%,P=0.002).A significant difference was observed between different age groups in the detection rate(2.5%vs.3.9%vs.4.1%vs.2.8%,P=0.005).The detection rate of SSA/P was I.I%(77/7332),and a significant difference was observed between different age groups in the detection rate(0.8%vs.1.3%vs.1.7%vs.0.8%,P=0.038).No significant difference was observed between male and female in the detection rate(1.2%vs.0.9%,P=0.243).2.232 patients with serrated lesions were composed of 154 patients with HP,77 patients with SSA/P and 1 patients with TSA.No significant differences were observed between patients with HP and SSA/P in age and sex(P=0.640;P=0.433).3.A total of 251 serrated lesions were detected,and composed of 165 HP(65.7%),85SSA/P(33.9%),and 1 TSA(0.4%),respectively.Significant differences were observed between HP and SSA/P in the location,size and morphology(P<0.001;P<0.001;P<0.001).85 SSA/P consist of 66 SSA/P with dysplasia(77.6%)and 19 SSA/P without dysplasia(22.4%),respectively.A significant difference was observed between the two groups in the morphology(P=0.015),whereas,no significant differences were observed in the location and size(P=0.932:P=0.211).4.232 patients with serrated lesions were composed of 5 patients with advanced adenoma,227 patients without advanced adenoma.The mean age of both were(64.8± 11.03)years and(52.11 ± 12.58)years,respectively.Advanced adenoma in patients with serrated lesions have a correlation with SSA/P which diameter≥ 10 mm(P=0.019),whereas,there was no correlation with HP which diameter≥10 mm(P=1.000),proximal SSA/P(P=0.215)and proximal HP(=1.000).Conclusion1.In the clinical,colorectal serrated lesions is relatively rare and the detection rate of it is low.2.The distribution of serrated lesions consists of a high proportion of HP,SSA/P and a low proportion of TSA.HP and SSA/P have their own endoscopic features,and combining with location,size and morphology of polyps helps us to distinguish them.However,with respect to endoscopic features of different pathological types of SSA/P,we still need to enlarge the sample size for further study.3.Patients which have diameter>10mm SSA/P,are easily associated with advanced of adenoma.If encountering with such patients in the clinical,we should as far as possible completely resect the lesion,with close follow-up and timely reexamination,on account of the high malignant potential of SSA/P and advanced adenoma. |
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