A Primary Study On The Diagnostic Value Of Confocal Laser Endomicroscopy In Colorectal Cancer

ObjectivesTo evaluate the diagnostic value of CLE in colorectal cancer,and to evaluate the possibility of CLE replacing the standard procedure of endoscopy-biopsy-pathology.MethodsWe selected the patients who were suspected to have colorectal malignant lesions by conventional endoscopy between April of 2008 and April of 2009 in Qilu Hospital of Shandong University. After the conventional endoscopy, sodium fluorescein (5 mL of a 10% sterile solution) was injected intravenously. At the site to be examined, after the mucosal surface was washed with 10 mL saline, confocal endomicroscopy was performed. During the examination of lesions, the distal tip of the endoscope was placed in gentle contact with the mucosa, then each lesion was observed from superficial to deep layers. All the images from above sites were stored digitally and a targeted biopsy of the examined areas was performed.The biopsy specimens were fixed in 4% methanal, embedded in paraffin,sectioned into 4μm thick samples, and stained with hematoxylin-eosin for histopathological examinations. The histopathologic images were diagnosed by two pathologists who were blinded to the CLE results and the diagnoses were confirmed by both. According to the diagnostic and grading criterias of colorectal cancer by CLE, we made diagnosis and gradings of all endomicroscopic images,then compared them with histological results,and calculate the sensitivity,specificity and agreement with histology,thus evaluate the diagnostic and grading value of CLE in colorectal cancer.Results37 patients who had completed CLE procedure were selected,39 lesions were examined by CLE,and 137 sites were also observed by CLE,then 103 biopsy specimens and 4593 images were aquired. Tissues and cellular structures of 65% of all these images could be identified clearly.39 lesions were suspected to be colorectal malignant lesions by conventional endoscopy,and were classified into two types, 14 elevated and 25 ulcerative type.33 lesions were diagnosed as cancer by CLE,of these 32 were identified by histology as cancer, 1 was identified adenomatous polyp.4 colorectal inflammation and 2 tubulovillous adenoma diagnosed by CLE were identified by histology.32 lesions were classified into three types,30 adenocarcinoma,1 mucinous adenocarcinoma,1 signet ring cell carcinoma,and were graded into 15 low differentiated cancer and 17 high differentiated cancer. But they were graded into 14 low differentiated cancer and 18 high differentiated cancer by CLE.The sensitivity, specificity and overall accuracy rate of CLE in diagnosing colorectal cancer is 100%,85.71%,97.44% respectively,and those of CLE in grading colorectal cancer is 80.00%,88.24%,84.38% respectively.The Kappa value of the diagnosis and grading of colorectal cancer by CLE and histology is 0.91 and 0.69 respectively.ConclusionsTo the patients who were suspected to have colorectal malignant lesions by conventional endoscopy, CLE has high sensitivity and specificity in diagnosing and grading colorectal cancer,and also has high agreement with histology in diagnosing and grading of colorectal cancer.In conclusion, CLE has great diagnostic and grading value in colorectal cancer.