Screening and rescreening for colorectal cancer. A controlled trial of fecal occult blood testing in 27,700 subjects

Abstract

All inhabitants of the city of Göteborg who in 1982 were between 60 and 64 years of age (27,700) were randomly divided into a test and a control group. The 13,759 subjects in the test group were invited to perform Hemoccult II (Smith Kline Diagnostic, Sunnyvale, CA) fecal occult blood testing over 3 days and to repeat the testing after 16 to 22 months. At the first screening 9,040 (66%) completed the test, and 7,770 (58%) completed the test at the second screening. In the first screening the test group was divided into two subgroups in which the tests were rehydrated and unhydrated before development. All tests were rehydrated in the second screening; 1.9% and 5.8% of the tests were positive in the unhydrated and rehydrated subgroups, respectively. The number of diagnosed neoplasms in the first screening was significantly larger (P less than 0.01) in the rehydrated group compared to the unhydrated group, 50 and 24 neoplasms, respectively. Sixteen of 61 carcinomas in the test group were found in the interval between the two screenings, 19 of the carcinomas at the second screening, and ten among the nonresponders. Rehydration of the Hemoccult II test is a necessity. Significantly more carcinomas (61) were found in the test group compared to the control group (20). There was a trend toward favorable tumor staging in the test group compared to the control group.

Effect of rehydration on guaiac-based faecal occult blood testing in colorectal cancer screening

“…of rehydrated HO as compared to unhydrated HO (8.9% vs 5.4%; non-significant difference) is somewhat surprising, nevertheless the higher cancer and adenomas detection rates observed in the rehydrated with respect to the unhydrated HO subgroup, are more likely to be ascribed to a higher sensitivity of rehydrated HO rather than to a higher prevalence of colorectal neoplastic lesions. When rehydration was introduced we did not observe a parallel decrease in the positive predictive value for cancer or adenoma, as reported by other authors (Kewenter et al, 1988). The increased recall rate to diagnostic assessment (5% vs 3.1%) with respect to unhydrated HO was quite acceptable in sight of the improved detection rate of cancer (0.37% vs 0.15%) and adenomas (1.06% vs 0.7%).…”

“…Rehydration of HO slides before development increases the sensitivity up to 85-90% (Kewenter et al, 1988) …”

“…Rehydration of HO slides before development increases the sensitivity up to 85-90% (Kewenter et al, 1988) Colorectal cancer incidence and mortality in the two areas were comparable, according to the Tuscany Cancer Registry (Buiatti et al, 1991).…”

Cost-Effectiveness Analysis of Screening for Colorectal Cancer in Japan.

“…Several randomized controlled trial (RCT) are now under way (Hardcastle et al 1985 ;Kewenter et al 1988;Winawer et al 1980). It is needless to say that the present analysis should be updated as the results of ROT becomes available.…”

Incidence of colorectal adenocarcinoma by anatomic subsite

“…years. [13][14][15][16][17] The need to understand patterns of tumor location within the colon and rectum is underscored Incidence rates were age-adjusted to the 1970 U.S. standard population, and plotted for the colon, recby the fact that screening endoscopy (flexible sigmoidoscopy) provides visualization of only the distal 60 cm tum, and subsites of the colon and rectum, and by stage, gender, and race. Time trends were plotted usof the colorectal surface, extending approximately to the splenic flexure.…”