Copyright ©The Author(s) 2002. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Feb 15, 2002; 8(1): 21-25
Published online Feb 15, 2002. doi: 10.3748/wjg.v8.i1.21
Early diagnosis for colorectal cancer in China
Ya-Li Zhang, Zhen-Su Zhang, Ba-Ping Wu, Dian-Yuan Zhou
Ya-Li Zhang, Zhen-Su Zhang, Ba-Ping Wu, Dian-Yuan Zhou, PLA Institute for Digestive Diseases, Nanfang Hospital, The First Medical University of PLA, Guangzhou 510515, Guangdong Province, China
Author contributions: All authors contributed equally to the work.
Supported by Key University Teacher Funds by the Ministry of Education
Correspondence to: Dr. Ya-Li Zhang, PLA Institute for Digestive Diseases, Nanfang Hospital, Guangzhou 510515, China.
Telephone: +86-20-85141544
Received: March 5, 2001
Revised: June 2, 2001
Accepted: June 25, 2001
Published online: February 15, 2002

AIM: To review the present studies on early diagnosis of colorectal cancer.

METHODS: The detective rate for early cancer is 1.7%-26.1% based on various statistical data, with much higher detective rate in endoscopy. Since early cancer means invasion involved in the mucosa or submucosa, the diagnosis can only be made when the invasive depth is identified. Pathological tissue materials from both surgical operation or endoscopic resection are suitable for early cancer evaluation.

RESULTS: Incidence of polyp malignancy is 1.4%-20.4%. The various constitutive proportion of polyps may explain the different rates. Malignant incidence is higher in adenomatous polyps, that for villous polyps can reach 21.3%-58.3%. Type II early stage of colorectal carcinoma is rarely reported in China. It is shownd that majority of them were not malignant, most of type IIa being adenoma or hyperplasia, and IIb being inflammatory and IIc might be the isolated ulcers. The occurrence of malignancy of type II is far lower than that of polypoid lesion. In China, the qualitative diagnosis and classification of neoplasm generally adopted the WHO standard, including surgical excision or biopsies. There is impersonal evaluation between colorectal pre-malignancy and cancer. The former emphasizes the dysplasia of nuclei and gland, while the latter is marked with cancer invasion. Diagnosis of early stage colorectal cancer in endoscopy is made with too much caution which made the detective rate much lower. Mass screening for asymptomatic subjects and follow-up for high risk population are mainly used to find the early stage colorectal cancer in China. Fecal occult blood test is also widely made as primary screening test, galactose oxygenase test of rectal mucus (T antigen), fecal occult albumin test are also used. The detective rate of colorectal cancer is 24-36.5 per 105 mass population.

CONCLUSION: Although carcinoma associated antigen in blood or stool, microsatellite DNA instability for high risk familial history, molecular biology technology for stool oncogene or antioncogene, telomerase activity and exfoliative cytological examination for tumor marker, are utilized, none of them is used in mass screening by now.

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