SCREENING FOR COLORECTAL-CANCER USING AN IMMUNOCHEMICAL TEST FOR FECAL OCCULT BLOOD - RESULTS OF THE 1ST 2 YEARS OF A SOUTH AUSTRALIAN PROGRAM

This paper reports an evaluation of the first 2 years of a South Austr alian screening programme for colorectal cancer which was established in 1988 by the Institute of Medical and Veterinary Science. The progra mme uses an immunochemical test for faecal occult blood. Based on 1 ye ar of follow-up, over the period of this analysis there were 24 cancer s and 99 adenomas detected in 6208 participants, and the estimated sen sitivity and specificity of the test (for colorectal cancer) were 82.8 and 95.9%, respectively. In many cases the test was used to detect re currence of disease in individuals with a previous diagnosis of colore ctal cancer. The estimated predictive value of a positive test for col orectal cancer in this population was 7.5%. Results suggest that parti cipants belonged to higher-than-average socio-economic groups and were more likely than the general population to have a family history of c olorectal cancer. Almost one-third had suffered from bowel symptoms in the 6 months before taking the test. These unique characteristics of participants, which limit the generalizability of results to the wider population, may result from the programme's reliance on self-recruitm ent methods. Consistent evidence for improvements in mortality in popu lations screened for colorectal cancer is still required before a reco mmendation for widespread screening in Australia can be made.