[A study on the complementary scheme of mass screening for colorectal cancer in an asymptomatic population].

Both SPA immunological fecal occult blood test (SPA FOBT test) and detection of T-antigen in rectal mucus (Shams' test) were used as screening tests in asymptomatic mass screening to evaluate the complementary effect of both tests for detection of colorectal cancers. SPA FOBT test showed a positive rate of 11.1% and shams' test 8.9% among 7,740 subjects. In 498 cases with positive screening test, 11 cases of carcinomas and 88 adenomas were found with colonoscopy. Only 9 cancers and 55 adenomas showed positive result in SPA FOBT test and 8 cancers and 51 adenomas in Shams' test. Both tests combined could enhance the detective rate of cancer in asymptomatic mass screening from 81.8% with SPA FOBT test or 72.7% with Shams' test to 90.9%. This complementary effect was more obvious in adenoma detection. It is suggested that there were some shortcomings in sequential FOBT test for cancer detection, the combined use of the two different screening tests for detection of colorectal cancer could decrease the rate of missed detection.

Comparison of Shams' test for rectal mucus to an immunological test for fecal occult blood in large intestinal carcinoma screening. Analysis of a check-up of 6480 asymptomatic subjects.

The sugar moiety detected from rectal mucus by the Galactose oxidase-schiff (Shams' test) is considered a substitutive test for immunological fecal occult blood test (FOBT) in screening colorectal carcinoma. Two strategies of screening were applied in 6480 subjects over 40 years of age, and 130 cm flexible colonoscope used for sigmoidoscopy or pancolonoscopy. Of them, 3820 were taken for immune FOBT (SPA test) and Shams' test. Only those who showed positive tests were chosen for 60 cm flexible sigmoidoscopy, while another 2660 subjects for both sigmoidoscopy and tests at the same time. Additionally, 130 cm flexible pancolonoscopy was carried out in 103 individuals with positive Shams' test for evaluating the false positive rate. Shams' test showed a sensitivity of 85.7% for colorectal cancer, 47.1% for adenomas in preselected patients, while the positive rate of SPA test were 90.5% and 41.2% respectively. In 3820 asymptomatic subjects undergoing sequential screening (aged 45 years and higher), Shams' test showed 9.1% positive, SPA showed 11.2% and 620 (16.2%) subjects were selected for sigmoidoscopy based on their positive galactose oxidase result or positive FOBT result. Two early stage carcinomas and 33 adenomas (0.32% and 4.2% respectively in sigmoidoscopy) were found. Another 2 660 subjects were taken for sigmoidoscopy screening. Four carcinomas and 78 adenomas were found. Of them, only two carcinoma (50%) and 17 (21.8%) or 22 (28.2%) adenomas were positive in Shams' or SPA test. But both tests combined in screening showed a rate of 61.3% in adenomas and 75.0% in cancers. 103 subjects with positive Shams' test were taken for pancolonoscopy. 82.5% showed no lesions.(ABSTRACT TRUNCATED AT 250 WORDS)