ABSTRACT
Objective To study the rules of circumferential margin invasion(CMI)in middle and(or)lower rectal cancers by pathological large slices stained with HE and labeled with CK20,and provide a pathological basis for clinical therapy of rectal cancer.Methods Forty-one patients with middle or low rectal cancer were randomly selected in 8 months.The surgically resected specimens were detected after they were made into the pathological large slices stained with HE and labeled with CK20.Results The mesentery CMI positive rate in the pathological slices with HE staining and CK20 labeling was 21.95%,and 29.27% respectively.The mesentery CMI positive rate in moderately-and well-differentiated group was lower than in poorly-differentiated group(P＜0.05).Moreover,the mesentery CMI rate was higher in the specimens with lower edge less than 5 cm away from the dentate line than that in those with lower edge more than 5 cm away from the dentate line(P＜0.05).There was no significant correlation between CMI with the factors such as gender,age,pathological general types,tumor infiltration depth,lymph node metastasis,and surgical procedures(all P＞0.05).Conclusion There were risk factors for the CMI such as low location,poor differentiation and so on.The CMI patients should be treated with standardized adjunctive therapy after operation.