No abstract

No abstract

Aims-To determine the harm that ensues from faecal occult blood (FOB) screening for colorectal cancer. Methods-150 251 people were randomly allocated either to receive biennial Haemoccult FOB tests (n =75 253) or not to be contacted (n=74 998). Study group patients returning positive tests were oVered colonic investigation; 1774 underwent complete investigation of the colon. Results-There was no significant diVerence in the stage at presentation of interval versus control group cancers. Survival in the interval cancer group was significantly prolonged compared with the control group. Sensitivity for colonoscopy or flexible sigmoidoscopy and double contrast barium enema (DCBE) was 96.7%. There were no complications of DCBE but seven (0.5%) complications of colonoscopy, of which six required surgical intervention. There were no colonoscopy related deaths. No patients without colorectal cancer died within 30 days of colonic investigation. Five patients died within 30 days of surgery for screen detected colorectal neoplasia and a further two died without having surgery. Six patients died after 30 days but within two years of surgery for screen detected benign adenomas or stage A cancers; in all cases the cause of death was not related to colorectal cancer. Conclusions-There was investigation related morbidity but no mortality and little to support overdiagnosis bias. The group returning falsely negative tests had a better outcome compared with the whole control group. There is a negative side to any screening programme but mortality reduction in this and other trials suggests that a national programme of colorectal cancer screening should be given consideration. (Gut 1999;45:588-592)

A total of 26,975 asymptomatic individuals were identified from family doctors' age/sex registers and randomly allocated to test or control group. The first test group (10,253) were offered 3-day fecal occult blood (FOB) testing; 3,613 (37%) completed the tests and 77 (2.1%) were found to be positive. In this group, 13 cancers were detected (3.5/1000 persons screened), of which 9 (70%) were Stage A. Of these subjects, 3349 have been rescreened at 2 years; 2799 (85%) completed the tests and 80 (2.8%) were found to be positive. Four cancers have been detected (three Stage A). In the whole test group followed for 2 years (10,462), 34 cancers have presented (17 screening detected, 3 interval cases in test responders, 14 symptomatic cancers in nonresponders), of which 14 (43%) were Stage A. In the control group (10,272 individuals), 17 patients have presented with symptomatic colorectal cancer during the 2-year follow-up, with rates of 0.9/1000 and 0.8/1000 persons/year in the first and second years of follow-up, respectively. No Stage A tumors were present. In the second test group (3,225) offered both guaiac (Hemoccult; Smith Kline Diagnostics) and immunologic (Feca EIA; Nordic) FOB tests, 1304 (44%) completed the tests, of which 126 (9.7%) were positive. Five cancers were detected (four Stage A), of which only three were positive by Hemoccult testing. In this group of test responders, one cancer has presented symptomatically at 1 year follow-up. Thus, at 2-year follow-up of the responding individuals of both cohorts of the initial screen of the test group, 5 of 21 cancers (24%) were negative by Hemoccult testing. Fecal occult blood testing has doubled the detection of colorectal cancer in the test group compared with the number presenting with symptoms in 2 years in the control group, and increased the proportion of early stage cancers (chi 2 = 8.0, P = less than 0.001).