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 Australian screening programme for colorectal cancer which was established in 1988 by the Institute of Medical and Veterinary Science. The programme uses an immunochemical test for faecal occult blood. Based on 1 year of follow-up, over the period of this analysis there were 24 cancers and 99 adenomas detected in 6208 participants, and the estimated sensitivity and specificity of the test (for colorectal cancer) were 82.8 and 95.9%, respectively. In many cases the test was used to detect recurrence of disease in individuals with a previous diagnosis of colorectal cancer. The estimated predictive value of a positive test for colorectal cancer in this population was 7.5%. Results suggest that participants belonged to higher-than-average socio-economic groups and were more likely than the general population to have a family history of colorectal 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-recruitment methods. Consistent evidence for improvements in mortality in populations screened for colorectal cancer is still required before a recommendation for widespread screening in Australia can be made.