Colorectal cancer screening: ensuring benefits outweigh the risks

To the Editor: We read with interest the article by Rosenfeld and Duggan,1 who speculate on the possible psychological downsides of colorectal cancer (CRC) screening with faecal occult blood testing, and possible barriers preventing women accessing screening. We are concerned that the article has multiple limitations, and would like to report prospective data on CRC screening in Australia.

While not mentioning three studies showing no long-term psychological harm from CRC screening,2 the authors have chosen to quote anecdotes from breast cancer screening, and a study of diagnostic testing for hepatitis C in a high-risk population, which is not a population screening test. Further, in the quoted study by Mant et al,3 an example they give of anxiety after a screening test, they neglected to mention that 98% of participants with false positive results felt the test worthwhile, and almost 40% were more likely to take part in other screening.

The quoted reduction of 16% in CRC mortality is from one trial only, and potentially misleading as, overall, the studies have shown a 15%–33% reduction in mortality.2 Benefit also goes well beyond reduced mortality, as the 20% reduction in incidence2 with early detection averts some of the physical and financial costs of surgery, radiation therapy and chemotherapy. Further, there are the definite negative impacts of dealing with the consequences of surgical management of a more advanced-stage symptomatic cancer (such as colostomy bags), compared with a screen-detected cancer managed by simple polypectomy. The additional negative effects of diagnosis of a potentially terminal illness are also relevant.

Data on participation in CRC screening are available from two sources. The National Bowel Cancer Screening Program evaluations to date have shown that significantly more women participate in the screening offer than men.4 Data from a multicentre Australian prospective CRC database5 reveal 56 of 619 cases in women (9.0%) and 65 of 759 cases in men (8.6%) were detected by screening.

Australia has been slow to adopt CRC screening despite the almost 5000 deaths annually, and the major potential benefits. Unlike Rosenfeld and Duggan, we argue that studies specific to CRC screening show no clear negative impact, and that the negative impacts of not screening are undisputed. Also, the available data indicate that women are participating in CRC screening to a greater extent than men.