Early colorectal cancer lesions is limited to the colon mucosa or submucosa of colorectal cancer. Now people think, colon mucosa from mild hyperplasia severe dysplasia is the evolution of early colorectal cancer pathology. Therefore, early detection of these lesions, the tumor treatment and prognosis of great significance. Shenyang Military Region General Hospital Jiayuting Professor at this meeting, endoscopic, biomarkers and pathology, etc., on the early diagnosis of colorectal cancer.
Endoscopic diagnosis of early colorectal cancer is the important technical means
Over the past 30 years, with the popularity of endoscopic and various endoscopic instrument development, innovation, made in the early diagnosis of colorectal cancer possible. In order to facilitate found lesions more clearly observe the subtle mucosal changes and determine the depth and scope of diseases, it is now already have developed some of the special features of endoscopic and related technologies: magnifying endoscopy (also known as expanded endoscopy), mucosal imaging can be more than 100 times magnification, focus on colon crypt openings change; endoscopic pigment spending cloth (also known as endoscopic pigment, usually with rouge indigo, violet blue and cresol as a sprinkling of cloth), through the distribution of pigment inflammatory lesions, tiny polyps and malignant polyps and make diagnosis; fluorescence (also known as fluorescence endoscopy), Lee by porphyrin derivatives in the accumulation in tumor tissue with a laser fluorescence them to indicate a need for biopsy material and focus on the location of positive detection rate; endoscopic ultrasonography (EUS), through endoscopic ultrasound equipment of tumor location, extent and concentration, the depth of tumor invasion - for accuracy rate of over 80%, while also in lymph nodes and distant organs whether transfer; MRI endoscopic images can be used to scan from the preoperative staging, the distal colorectal cancer diagnosis preoperative staging is a simple method; CT image reconstruction colonoscopy (CTC), or CT “colonoscopy.” Application of the technology is not colonoscopy, instead of using the CT will be the point of the colon (2D and 3D) imaging data, the screening without pain, easier for patients to accept.
Biomarker detection is a new way
Endoscopy, imaging and histopathologic examination Although from the shape and structure for early colorectal cancer found to provide a reference, but not necessarily to achieve early detection, early diagnosis purposes. In recent years, both at home and abroad, the researchers found that certain tumor biomarker, such as tumor-associated antigens, hormones, receptors, enzymes, such as tumor gene product and the changes in the tumor and development. If familial adenomatous polyposis gene (FAP), mismatch repair genes (MMR) and insulin-like growth factor-1 (IGF-1), k-ras gene, p53 gene, these markers used alone or in combination with early colorectal cancer detection sensitivity and specificity , were significantly higher than the occult blood test results. These two methods of detecting colorectal adenomas sensitivity and specificity were 70% and 90%.
Pathologic diagnosis should quantify the diagnostic criteria
Through pathological examination of the results obtained, mainly based on the naked eye doctors pathological observation, judgment, but different pathologic specimens by the same doctor made the judgment often have some differences. So, as far as possible, should be quantified pathological diagnosis criteria, such as abnormal glands, nuclear / cytoplasm ratio of nuclear and high standards mean nuclear area, would make it possible to reduce human error in the diagnosis, thereby further improve the early diagnosis of colorectal cancer.
In addition, the application of principles of organization of early diagnosis of colorectal cancer at the same time, can not ignore the role of cytologic diagnosis. The normal intestinal epithelium updated every 72 hours, a cubic centimeter of colorectal tumors have a day × 108 cells exfoliated. Therefore, from the stool, for the tumor cells early colorectal cancer diagnosis is one of the important ways. This is a non-invasive, simple and reliable diagnostic methods.
A variety of techniques can be combined to improve the diagnosis rate
Currently, early detection of colorectal cancer mainly by means of endoscopy, special endoscopic, and other pathological test. The development of these technologies will undoubtedly increase early detection, early diagnosis of colorectal cancer risk. However, although the endoscopic examination of the lesion may direct, and easy to find disease, mucous membrane color change significantly uplift of the lesion, but right type of surface lesions are difficult to detect. Large pigment or combining fluorescence endoscopy Although technology can improve the early diagnosis of colorectal cancer, this is still the naked eye observation, coupled with the experience and endoscopic doctors of different levels, it is inevitable there will be judgment errors and missed diagnosis. In addition, the biopsy site and the difficulty of accurate pathologic findings are directly affecting factors. Even pathological examination of the vast majority of lesions can be given certain diagnosis, but for individual lesions, especially for the grade dysplasia and severe dysplasia and early cancer boundaries, pathological physicians sometimes have differences of judgment, its conclusions are often different. In recent years, despite domestic and international right of the colorectal cancer markers made many studies, especially some of the gene markers have been found for the early diagnosis of colorectal cancer provides new means, but so far the ideal sensitivity and specificity of tumor biomarker very little. At present, even in the detection of doctors found signs of positive reaction, we can only make the conclusions of suspected cancer, if further confirmed by endoscopy and pathology examination needed help.