The Mesorectal Invasion Detected By HE And CEA Immunohistochemical Staining In Rectal Carcinoma

[Objective]To investigate the feasibility and reliability of HE and CEA immunohistochemical staining in detecting mesorectal invasion,micrometastases and CRM involvement in middle and low rectal cancer patients.[Methods]40 middle and low rectal cancer patients were treated in the Affiliated Hospital of Qingdao University Medical College between Oct 2007 and Sep 2008.All patients were diagnosed by electronic colonoscopy and biopsy,and underwent operations by the same surgeon according to the TME(Total Mesorectal Excision) principal.The radical excision(RO):a excision with no residual macroscopic tumor,free margins including perirectal mesorectal margins on routine microscopic examination and no evidence of distant metastasis.After the operation, the specimen were scored 3 points-good:Intact mesorectum with only minor irregularities of a smooth mesorectal surface.No defect is deeper than 5mm.No coning on the specimen.Smooth circumferential resection margin(CRM) on slicing. The specimen was dissected in each 1cm,and these sections include the whole tumor and the edge of the tumor invasion in mesorectum.After paraffin imbedding,the sections was cut at 4μm continuously.The specimen were then proceed for H-E and CEA immunohistochemical staining.The sections were examined by two experienced pathologists.The examination include the circumferential resection margin involvement,the tumor invasion layer.The control study was acted based on these information.These cases' clinical and pathological factors was documented, and the feasibility and reliability of CEA immunohistochemical staining in the detection of tumor micro invasion and mesorectum micrometastasis was analyzed. All the data was analyzed by SPSS12.0 for windows.[Results]25%(10/40) of all cases were found circumferential resection margain invasion in CEA staining,comparatively in HE staining the rate was 15%(6/40). There wer significant difference between the HE and CEA staining methods in CMR invasion detection.27(67.5%) cases were detected mesorectal micrometastesis by CEA staining,the specificity:88.2%,the sensitivity:100%,and accuracy:90% respectively.The mesorectal invasion was related with carcinoma invasion degree (X2=13.143,P=0.022),serum CEA level higher than normal(X~2=7.403,P=0.011), tumor differentiation(X~2=7.718,P=0.020),and no significant correlations with the mesorectal micrometastasis detection by CEA staining with tumor location (X~2=1.955,P=0.524),and lymph nodes staging(X~2 =4.046,P=0.185). [Conclusions]CEA staining is useful in the detection of mesorectal invasion, CRM involvement in middle and low rectal cancer.The high risk factors with mesorectal micrometastases was:tumor invasion degree,serum CEA level,and differentiation of tumor.